highaltitude.log.20090323

[00:06] <natrium_> hi
[00:07] <natrium_> SpeedEvil, "Fellow HAM user Calvin Janes, VO1CAL, has graciously offered to help in recovery of the payload. He is located 25 miles east of Trinity."
[00:07] <natrium_> "Recovery team deployed."
[00:07] <natrium_> :D
[00:08] <shellevil> yeah - there are actually quitte a lot of people in easy driving distance.
[00:08] <shellevil> If they are willing to do a 10 mile or so hike
[00:08] <shellevil> or maybe google doesn't map all the roads - which is quite likely
[00:09] <natrium_> or they use off-road vehicles
[00:09] <shellevil> that too
[00:09] <natrium_> although there seem to be many hills
[00:10] <natrium_> they could keep along the lakes
[00:10] <natrium_> it's a bit surprising that they decided to retrieve it in the dark
[00:10] <sYx66> natrium, do you have the gps data and all?
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[00:11] <natrium_> yeah, i can put it up
[00:12] <sYx66> anything interesting?
[00:12] <sYx66> what happened to gps?
[00:14] <natrium_> it failed at 18km
[00:14] <shellevil> maps.live.com has a slightly better map - though no names.
[00:14] <natrium_> and resumed when it went below 18km again
[00:15] <sYx66> ah ok
[00:23] <natrium_> sYx66, http://wiki.ukhas.org.uk/projects:halo_flight3_log
[00:24] <sYx66> highest speed 76km/h
[00:24] <sYx66> you should get a speeding ticket
[00:24] <natrium_> Date: 210309, Time: 190031.950, Pos: 43.637383, -80.714058, Alt: 9677.0, Heading: 161.5, Speed: 100.4, Valid: 1, Fix: 3, Num Sats: 11
[00:24] <sYx66> oh i found 88.5
[00:24] <natrium_> 100.4
[00:24] <natrium_> :P
[00:25] <sYx66> hmm there's one with 256.1
[00:25] <sYx66> is that an error?
[00:25] <sYx66> Date: 210309, Time: 182600.940, Pos: 43.697483, -81.004333, Alt: 17804.6, Heading: 204.6, Speed: 256.1, Valid: 0, Fix: 1, Num Sats: 0
[00:25] <sYx66> also 128
[00:25] <natrium_> those are > 18km
[00:25] <sYx66> we might of broken a record of sorts
[00:25] <natrium_> so it's all messed up
[00:25] <sYx66> ah
[00:25] <sYx66> well alt is 178
[00:26] <natrium_> that's messed up
[00:26] <natrium_> landing speed was 4.79 m/s
[00:29] <natrium_> going to make kml
[00:31] <sYx66> going to loo now. later
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[00:39] <Laurenceb> http://imagebin.org/42348
[00:39] <Laurenceb> thats a sim of my gps velocity correction
[00:39] <Laurenceb> seems to work acceptably
[00:40] <Laurenceb> in an ideal case it would be a thin circle
[00:40] <Laurenceb> the spikes around the edge are wind gusts and gps constellation changes
[00:42] <Laurenceb> thats a plot of all corrected velocity vectors
[00:46] <natrium_> does it handle the spikes?
[00:46] <Laurenceb> those are partly from the fact I'm extropolating velocity from pos change
[00:46] <Laurenceb> the firmware uses the velocity output
[00:46] <Laurenceb> thats based of carrier phase
[00:47] <Laurenceb> so its more stable and doesnt have jumps
[00:47] <Laurenceb> at least not as bad
[00:47] <Laurenceb> gusts arent a huge problem as the gyro is good
[00:47] <Laurenceb> and I put the gps heading as having very large error
[00:48] <Laurenceb> ~20 degrees
[00:48] <Laurenceb> so it coasts over them over timescales or 4 or 5 seconds
[00:49] <Laurenceb> the good thing is theres a big hole in the middle :P
[00:49] <Laurenceb> that means I can maintain control very well
[00:50] <Laurenceb> I'm playing with different layer thicknesses
[00:50] <Laurenceb> about 120m works best, I was flying with 100m so a good guess
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[00:52] <natrium_> HALO3 KML --> http://www.natrium42.com/balloon/flight3/halo3.kml
[00:54] <Laurenceb> nice
[00:54] <Laurenceb> using the micro sd?
[00:54] <natrium_> yep
[00:55] <Laurenceb> nice work
[00:55] <natrium_> 8GB microSDHC
[00:55] <Laurenceb> hehe
[00:55] <natrium_> way too big, but it had SPI as opposed to other cards i tried
[01:00] <Laurenceb> hmm think I'm going to have to move away from a layered atmospheric model
[01:01] <Laurenceb> this gets suprisingly complex...
[01:43] <Laurenceb> anyone used octave here?
[03:01] <natrium_> hehe, i sent an email to venus chip manufacturer about the 18km bug :P
[03:08] <Laurenceb> :P
[03:08] <Laurenceb> http://wiki.ukhas.org.uk/_media/track.kml.zip?id=list_of_launches&cache=cache
[03:15] <Laurenceb> "Fellow HAM user Calvin Janes, VO1CAL, has graciously offered to help in recovery of the payload. He is located near Trinity"
[03:15] <Laurenceb> what the hell?!
[03:15] <Laurenceb> how do they find these people
[03:15] <Laurenceb> thats like a few houses 5 miles away
[03:16] <Laurenceb> its like you could land anywhere :P
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[04:34] <natrium_> sYx66, i created a kml from the data http://www.natrium42.com/balloon/flight3/halo3.kml
[04:36] <sYx66> zooming in
[04:37] <sYx66> hmm looks like it's drunk
[04:37] <sYx66> looks like it did use parachute too
[04:37] <natrium_> yes
[04:38] <natrium_> descent rate was close to the calculation
[04:38] <sYx66> 5?
[04:43] <natrium_> about 4.8m/s
[04:43] <natrium_> so, i emailed the gps chip guys :)
[04:44] <natrium_> they say that they can give firmware which works above 18km for the flash version of the gps chips
[04:45] <natrium_> maybe i can get a few samples
[04:45] <natrium_> since they acknowledge their mistake in the datasheet
[04:47] <natrium_> might even get some for free :)
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[07:36] <jcoxon> morning
[08:16] <icez> morning
[08:16] <icez> uhm...that was late
[08:17] <jcoxon> hehe
[08:17] <jcoxon> hey icez, haven't spoken to you for a while
[08:20] <icez> yeah
[08:21] <icez> been kept busy :[
[08:21] <natrium_> yo jcoxon
[08:21] <natrium_> bill pointed me to this gps module --> http://inventeksys.accountsupport.com/products/category.php?id_category=5
[08:22] <natrium_> sirfIII and works to 125k ft
[08:22] <natrium_> ordered one with overnight shipping
[08:23] <jcoxon> great
[08:23] <icez> i'm confused on the wiki why UTennessee is part of the UK records :P
[08:23] Action: natrium_ Zzz
[08:23] <jcoxon> night natrium_
[08:23] <natrium_> nite all
[08:23] <icez> night
[08:24] <jcoxon> icez, ummm where?
[08:24] <jcoxon> http://wiki.ukhas.org.uk/general:uk_records
[08:24] <icez> Icarus II?
[08:24] <jcoxon> no thats rjharrison's payload
[08:25] <icez> ah
[08:25] <icez> 35k km is pretty nice
[08:26] <icez> well, sleepy time
[08:27] <jcoxon> yeah, was a great launch
[08:27] <jcoxon> night icez
[08:27] <icez> night
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[09:24] <jcoxon> hey G8KHW
[09:24] <jcoxon> just the person i want to speak to
[09:25] <jcoxon> i was wondering how i could adapt your MFSK code to accept a string on the command line, am planning to generate a test wav file of mfsk data
[09:31] <gordonjcp> jcoxon: got a link to the code?
[09:32] <jcoxon> unfortunately not
[09:33] <jcoxon> that said the hardcoded message is:
[09:34] <jcoxon> u08 Test [] = "THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG 0123456789 \
[09:34] <jcoxon> the quick brown fox jumped over the lazy dog <[{(@#)}]> ????? ?????";
[09:34] <jcoxon> so i guess i need to convert a string to u08
[09:36] <jcoxon> and replace Test with it
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[10:04] <jcoxon> fixed it
[10:04] <jcoxon> no worries
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[11:25] <fergusnoble> edmoore: yo
[11:27] <SpeedEvil> yo
[11:28] <edmoore> hi fergusnoble
[11:29] <fergusnoble> edmoore: good suggestion for the predictor
[11:30] <edmoore> ta.
[11:30] <fergusnoble> i guess maybe the best thing would be to fit it to the nasa model?
[11:30] <edmoore> it is because there is now a really good incentive to get the landing spot prediction as accurate as possible
[11:30] <edmoore> (have a guess... and maybe guess via PM)
[11:30] <fergusnoble> why now especially?
[11:34] <fergusnoble> out of interest was the predictor ever run for the actual launch time?
[11:38] <edmoore> fergusnoble: nope! It was run for the anticipated time, then we had about 1.5hrs of 'just five more minutes'
[11:38] <edmoore> and I think the winds changed reasonably significantly in that time
[11:39] <fergusnoble> yup
[11:39] <SpeedEvil> Where were you expecting it to end up?
[11:39] <edmoore> certainly they must have got faster. 4m/s got us float time for an earlier launch, Didn't even get close in the event.
[11:44] <edmoore> http://vimeo.com/3803248
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[12:27] <edmoore> hi Tigga
[13:28] Tigga_ (n=chatzill@apple3feet.plus.com) joined #highaltitude.
[13:28] <edmoore> Tigga_ http://vimeo.com/3803248
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[13:29] <Tigga_> edmoore: excellent
[13:29] <edmoore> pretty
[13:29] <Tigga_> is that madsen's?
[13:29] <edmoore> shame about height. I want to try again!
[13:30] <edmoore> I think so yes
[13:30] <Tigga_> hehe
[13:30] <Tigga_> well we didn't have to hacksaw anything
[13:30] <Tigga_> pretty much everything is still intact... need to restring some bits
[13:30] <Tigga_> and cutdowns....
[13:33] <Tigga_> had a look at the prediction software, could only find the old source. It's probably on the SVN.
[13:33] <Tigga_> and I couldn't find any interpolation code that actually ran... which was a bit odd
[13:33] <Tigga_> might look @ svn
[13:33] <edmoore> it's linear currently as i understand
[13:34] <Tigga_> seems logarithmic would certainly be better
[13:34] <Tigga_> though tbh the main errors seem to come from ascent and descent rates
[13:35] <Tigga_> hmm
[13:35] <Tigga_> actually maybe not logarithmic
[13:35] <Tigga_> I'd have to look at some data :P
[13:36] <edmoore> well the model
[13:36] <edmoore> nasa model
[13:36] <Tigga_> for wind speed?
[13:36] <edmoore> no
[13:36] <edmoore> atmospheric pressure/altitude/temp
[13:36] <Tigga_> isn't wind speed what we're interpolating?
[13:36] <edmoore> but more important is that it gets it right during an actual flight
[13:36] <edmoore> no
[13:37] <Tigga_> okies - not familier enough with it
[13:37] <edmoore> well yes, we're interpolating wind speed, but as a function of 3D position
[13:37] <edmoore> and 1D (altitude) of that should have nonlinear interpolation
[13:37] <edmoore> vs linear interpolation in latitude and longitude
[13:38] <edmoore> I think
[13:49] <Tigga_> well is wind speed logarithmic?
[13:49] <Tigga_> I'm not sure
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[13:57] <Tigga_> http://www.centennialofflight.gov/essay/Theories_of_Flight/atmosphere/TH1G3.jpg - seems a 32 point linear interopolation of this isn't going to be too bad
[14:01] <hallam> hey gang
[14:08] <edmoore> hi hallam
[14:14] <hallam> looks like the sky was too bright for any useful star data :/ but I think the dual balloon launch was definitely worth doing
[14:14] <hallam> I'd be up for going again with less of an underfill
[14:14] <edmoore> it's a shame. The winds must have definitely picked up
[14:15] <edmoore> we were simming float time even with 4m/s ascent
[14:15] <edmoore> but it's a very useful data point, yes
[14:15] <hallam> yeah it was moving pretty quickly
[14:15] <edmoore> and worth doing again. soon.
[14:15] <hallam> Tigga_, did you get a chance to download the badger logfile?
[14:15] <edmoore> maybe we could incorporate a sponsor thing onto the next one
[14:15] <hallam> sure
[14:16] <hallam> there doesn't seem to have been any damage to any of the vehicle
[14:16] <hallam> and we tried to de-rig it for recovery fairly carefully
[14:16] <hallam> from the auto-exposure photos, things went very orange shortly after cutdown
[14:17] <edmoore> :)
[14:17] <edmoore> not suprising
[14:18] <edmoore> there wasn't that much england left either
[14:18] <hallam> indeed
[14:18] <hallam> I don't actually have the final landing site coords here
[14:18] <edmoore> we'll have to be careful next time - if we'd got to 30km, it might have started getting a little nail biting
[14:18] <hallam> I was wishing I'd kept the distance cutdowns at 70km
[14:19] <edmoore> why?
[14:19] <hallam> instead of 80
[14:19] <hallam> during the chase when it looked like it might be headed for the sea
[14:19] <edmoore> they were 80 originally, changed to 90
[14:19] <edmoore> iirc
[14:20] <edmoore> i think if it'd gone to 30km, it would still have come down on land. Just flirting with danger a bit more
[14:21] <hallam> it wasn't very comfortable doing the chase without predictor software in the car
[14:21] <edmoore> things were sound, but the winds were def stronger than expected. Still, that can be fixed for next time round
[14:22] <hallam> yup
[14:22] <hallam> am I right in thinking that Sal's cutdown was on the pilot?
[14:22] <edmoore> yep
[14:22] <hallam> so it never got tested, bum
[14:22] <hallam> I guess it got the test of not breaking during ascent
[14:23] <edmoore> sure?
[14:23] <edmoore> I don;t remember what the logic was
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[14:24] <hallam> first cutdown fires at 26km altitude, 2nd at 88km distance, 3rd at 90km distance
[14:25] <hallam> telemetry said 2 and 3 both went as programmed, but 1 never did because it never got high enough
[14:25] <hallam> hi jcoxon
[14:25] <fergusnoble> hi all
[14:25] <edmoore> fergusnoble: could you confirm the above?
[14:25] <fergusnoble> hallam: yeah, in retrospect we didnt really account for reaching the distance before the altitude
[14:25] <edmoore> ok cool
[14:26] <fergusnoble> i coded what was written on the board in the IfM
[14:26] <jcoxon> hey hallam
[14:26] <edmoore> hi jcoxon
[14:26] <edmoore> launch vid for you http://vimeo.com/3803248
[14:26] <fergusnoble> which was fire 1 at 25km and 2 and 3 at 120km
[14:26] <hallam> I guess in theory the distance condition should have fired 1 at the same time as 2
[14:26] <hallam> but because 3 was on both strings, it didn't really matter
[14:26] <edmoore> yes
[14:26] <fergusnoble> yeah, exactly
[14:27] <fergusnoble> did the badger log ok?
[14:27] <hallam> don't know, it's still with Tigga_
[14:27] Action: jcoxon is ill
[14:27] <jcoxon> urgh
[14:28] <fergusnoble> jcoxon: :(
[14:28] <hallam> :( what have you got?
[14:28] <jcoxon> sore throat, feel quite 'groggy'
[14:28] Action: hallam has had a killer throat since Saturday night
[14:30] <jcoxon> it no fun
[14:30] <jcoxon> it is*
[14:30] <hallam> fergusnoble: I did depower the badger when we found it, so it shouldnt' have overwritten the log or anything
[14:31] <fergusnoble> ok, cool, well it knows not to overwrite an existing file
[14:32] <fergusnoble> hallam: can you confirm that you actually set cutdown 2 to go at 88km as is indicated by the radio log?
[14:32] <hallam> yes
[14:32] <fergusnoble> and 3 to go at 90km
[14:32] <fergusnoble> ok, cool
[14:32] <hallam> #define MAX_RANGE_1 88 #define MAX_RANGE_2 90
[14:33] <Tigga_> I'll just look at the badger now
[14:33] <fergusnoble> was a bit worried as people were saying it was 90 but the badger clearly tried to cutdown at 88
[14:33] <hallam> I suggested 80, Ed suggested 90, I coded 88
[14:33] <Tigga_> we had a bit of spare land....
[14:34] <jcoxon> bbiab
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[14:34] <hallam> Tigga_: sweet, dead keen to see the minute or two of descent under the pilot balloon between 88km and 90km
[14:34] <fergusnoble> we should change the flight logic to fire cutdown 1 at 88km too, as with nova 10 if cutdown 3 hadnt worked we would have been screwed
[14:34] <hallam> yeah definitely
[14:34] <edmoore> yep
[14:34] <Tigga_> anything careful I should avoid?
[14:35] <Tigga_> or is it ok just to take the card out?
[14:35] <hallam> unplug battery first
[14:35] <fergusnoble> just take it out
[14:35] <hallam> then take card out
[14:35] <fergusnoble> can take the batt out iuw
[14:36] <fergusnoble> Tigga_: if you email me the log i can run it through my decoder
[14:36] <fergusnoble> to chuck out kmls and temp graphs
[14:37] <edmoore> back later/tomorrow
[14:39] <hallam> bye Ed
[14:40] <fergusnoble> hallam: so really no useable data?
[14:40] <fergusnoble> that sucks
[14:40] <fergusnoble> are you in devon now?
[14:40] <Tigga_> fergusnoble: which file do we want? I have log18.txt which looks likely. 983kb.
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[14:40] <fergusnoble> whichever is the biggest probably
[14:41] <Tigga_> that is
[14:41] <fergusnoble> ok, cool
[14:41] <fergusnoble> can you email it to me?
[14:41] <hallam> cc me please
[14:41] <hallam> fergusnoble: yep, in Devon - haven't totally looked at all the data, but it doesn't look promising so far. But I'm not displeased as it was a very experimental flight
[14:42] <fergusnoble> hallam: i'll email the list in a sec with the kml
[14:42] <hallam> I guess I'm most interested in an altitude vs time plot
[14:43] <Tigga_> will do
[14:44] <edmoore> can the list get the raw data too?
[14:44] <hallam> I'm really sorry about the lack of inertial data, it was a bit flaky but I'd thought I'd fixed it
[14:47] <fergusnoble> hallam: ill put the processed data on the wiki along with the raw. my log processor spits out an alt/time plot
[14:48] <hallam> nice :)
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[14:58] <fergusnoble> Tigga_: there was no corruption of the disk?
[15:07] <Tigga_> fergusnoble: sorry - forgot to hit the send button and ate lunch instead
[15:07] <hallam> don't worry, lunch is important
[15:08] <Tigga_> should be flying over the cables now
[15:33] <Tigga_> how did we start descending before cutdown 1?
[15:34] <Tigga_> aah - logs only show 1 cutdown
[15:43] <hallam> they do?
[15:44] <hallam> I don't see the cutdown information in the log?
[15:44] <hallam> or is it another file
[15:50] <Tigga_> line 9201
[15:50] <Tigga_> I think
[15:51] <Tigga_> fairly sure I sent you the correct file
[15:52] <hallam> hm
[15:53] <hallam> I see it, but telemetry was definitely indicating first cutdown 2, then cutdown 3
[15:53] <hallam> maybe cutdown 3 wasn't logged
[15:54] <Tigga_> well the first cutdown doesn't seem to have been logged
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[15:54] <Tigga_> it descends befre the logged one
[15:59] <hallam> I think jcoxon has a log of the received telemetry, there
[15:59] <hallam> there's a partial log on Ed's laptop
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[15:59] <aLeXBrEtOn> hello all
[15:59] <Laurenceb> hi
[15:59] <Laurenceb> hallam: how was the recovery?
[15:59] <aLeXBrEtOn> any news on the balloon in newfoundland?
[16:01] <Laurenceb> not from me
[16:01] <hallam> Laurenceb: pretty good, we drove to the predicted site and picked it up on the yagi, then went to the actual site
[16:01] <Laurenceb> neat, but it cutdown too soon
[16:01] <hallam> which was corn stubble
[16:01] <hallam> not really
[16:01] <Laurenceb> I was trying to get it in guildford
[16:02] <hallam> I think 10km from the sea is close enough for me
[16:02] <Laurenceb> think I got it just after cutdown for about 15 minutes
[16:02] <Laurenceb> but it was too noisy from my window - theres a courtyard
[16:02] <Laurenceb> it didnt do the apogee float?
[16:02] <SpeedEvil> I think if it had gone all the way to planned altitude someone'd have been getting the chunnel :)
[16:03] <SpeedEvil> I wonder what the customs implications of 'exporting' stuff like that are.
[16:03] <Laurenceb> haha
[16:04] <Laurenceb> thats a point, we could strap drugs to the transatlantic
[16:05] <hallam> yeah, well, speaking of not-totally-retarded ideas
[16:05] <Laurenceb> wonder if you could launch from colombia
[16:06] <hallam> the distance cutdowns triggered at 19km altitude
[16:06] <aLeXBrEtOn> guys
[16:06] <hallam> planned floats was 26
[16:06] <aLeXBrEtOn> just got details from out sponsors
[16:06] <aLeXBrEtOn> apparently any project has to be profitable in order for them to sponsor it
[16:06] <Laurenceb> are the photos blurred?
[16:06] <aLeXBrEtOn> any ideas on how we can make money from this?
[16:06] <Laurenceb> aLeXBrEtOn: you part of CU spaeflight?
[16:06] <aLeXBrEtOn> (a balloon with a camera)
[16:07] <aLeXBrEtOn> no
[16:07] <aLeXBrEtOn> I am part of a separate team with Drebellion
[16:07] <aLeXBrEtOn> who was on yesterday
[16:07] <Laurenceb> oh yes wd
[16:07] DRebellion (n=DRebelli@unaffiliated/drebellion) joined #highaltitude.
[16:07] <Laurenceb> *wb
[16:08] <hallam> aLeXBrEtOn: I'd recommend looking for another sponsor
[16:08] <aLeXBrEtOn> like the local paper?
[16:08] <hallam> the idea is, the sponsor gets to put their logo on the side of your project, and any exposure it gets gives them advertising
[16:08] <Laurenceb> alternatively, photoshop
[16:08] <hallam> who did you approach that told you it had to directly make them profit?
[16:09] <hallam> because that's investment, not sponsorship
[16:09] <SpeedEvil> aLeXBrEtOn: you're back to the 'strap drugs to it' thing then if you need a profit.
[16:09] <aLeXBrEtOn> yep
[16:09] <aLeXBrEtOn> thing is
[16:09] <Laurenceb> still need to buy tickets to columbia
[16:09] <aLeXBrEtOn> the school asks 'how are you going to make money?' on the sponsorship form
[16:10] <Laurenceb> then you can get "high"
[16:11] <SpeedEvil> ask local papers and stuff if they'd be willing to sponsor photos of team/launch that they could then use. Again, photogenic team members'd help
[16:12] <Laurenceb> whats the twitter page for the newfoundland balloon?
[16:17] <Laurenceb> interesting ideas with the predictor
[16:17] <Laurenceb> so you fit the nasa model to the GFS data by tweaking some coefficient
[16:18] <Laurenceb> - tweaking temperature, height iof tropopause ectr
[16:18] <Laurenceb> - lapse rate
[16:20] <SpeedEvil> goog;le gbh3 iirc
[16:20] <Laurenceb> hallam: hard luck on the sky vbrightness
[16:21] <Laurenceb> grevious bodily harm?
[16:21] jcoxon (n=jcoxon@host86-145-224-2.range86-145.btcentralplus.com) joined #highaltitude.
[16:21] <Laurenceb> gbh3?
[16:21] <SpeedEvil> https://explore.twitter.com/PBH3https://explore.twitter.com/PBH3
[16:22] <DRebellion> aLeXBrEtOn, no they don't!
[16:23] <Laurenceb> no updates
[16:23] <DRebellion> aLeXBrEtOn, I've just read all the information i could find
[16:23] <DRebellion> there is no mention of profit anywhere
[16:23] <DRebellion> "funding the cost of materials for a science based project, a community project or a conservation project. "
[16:23] <DRebellion> "The awards are for projects or activities which will benefit you but which have an educational, scientific, charitable, sporting or cultural purpose."
[16:24] jiffe92 (n=weechat@64.251.162.157) left irc: "WeeChat 0.2.6"
[16:25] <Laurenceb> Im going to go for a second rogallo launch very soon
[16:25] <SpeedEvil> Good luck.
[16:25] <Laurenceb> I think the wind records from ascent will be acvceptable, but I'm going to improve the wind estimation
[16:25] <SpeedEvil> trim changes, glue the knot, software changes,
[16:25] <Laurenceb> thanks
[16:26] <Laurenceb> yeah
[16:26] <DRebellion> Quick question: anybody know if we can 'filter' an LDR to UV only?
[16:26] <DRebellion> would be a neat experiment to measure levels
[16:26] <SpeedEvil> yes
[16:26] <Laurenceb> I've written some sim code oin octave to look at the wind estimation
[16:26] <hallam> can be done
[16:26] <SpeedEvil> though LDRs may not actually be very sensitive at UV
[16:26] <DRebellion> mmm
[16:26] <Laurenceb> yeah
[16:27] <hallam> yeah, you might use a photodiode instead
[16:27] <Laurenceb> LDRs suck to be honest
[16:27] <Laurenceb> yep
[16:27] <Laurenceb> photodiodes are much more well behabved
[16:27] <SpeedEvil> Laurenceb: they do have _huge_ signal outputs tho
[16:27] <Laurenceb> true
[16:27] <hallam> basically nobody uses LDRs after secondary school
[16:27] <Laurenceb> I tired taking ldrs to the limit to make a durgular alarm
[16:27] <DRebellion> Ok, thanks.. I'll look into photodiodes
[16:27] <DRebellion> hehe
[16:27] <Laurenceb> oh god
[16:27] <Laurenceb> burgular
[16:28] Action: SpeedEvil passes Laurenceb a club.
[16:28] <Laurenceb> it could detect people at the other side of the road
[16:28] <Laurenceb> but was vulnerable to temperature changes
[16:28] <Laurenceb> causes by wind ect
[16:29] <Laurenceb> most of the errors in heading seem to be caused by gusts of wind and gps noise
[16:30] <Laurenceb> I can reduce error a buit by moving to 120m layers
[16:30] <Laurenceb> if I go for a gaussian weighted rolling average of windspeed and optimise the roll off I can improve things a bit more
[16:31] <Laurenceb> but its only about 66% of the error with 100m layers
[16:32] <Laurenceb> I want all the data to fit into 512bytes of eeprom
[16:32] <Laurenceb> so this is a little tricky...
[16:34] <Laurenceb> previously I stored wind in m/s as a signed char
[16:34] <SpeedEvil> 240MPH!
[16:34] <DRebellion> Ok... so we've (alex, me, and daniel) decided to call the project ALIEN: altitude imaging entering near-space : P . Anyway, we need a wiki. Is it appropriate to create http://wiki.ukhas.org.uk/projects:alien ?
[16:34] <SpeedEvil> sure
[16:35] <DRebellion> great
[16:35] <DRebellion> : )
[16:35] <Laurenceb> maybe I could store wind and its forst differential
[16:35] <Laurenceb> thats probably best
[16:35] <aLeXBrEtOn> ok
[16:35] <SpeedEvil> DRebellion: though that is a rather forced acronym.
[16:35] <DRebellion> i know
[16:35] <aLeXBrEtOn> yes
[16:35] <DRebellion> any better ideas xP
[16:35] <aLeXBrEtOn> we had Daedalus
[16:35] <DRebellion> doesn't roll off the tongue as well as his son
[16:36] <aLeXBrEtOn> Icarus..great name, already taken
[16:36] <DRebellion> indeed
[16:36] <aLeXBrEtOn> so
[16:36] <DRebellion> aLeXBrEtOn, ok last chance
[16:36] <DRebellion> any better ideas?
[16:36] <aLeXBrEtOn> ermn
[16:36] <DRebellion> got until 5pm k?
[16:36] <DRebellion> bbl
[16:36] <aLeXBrEtOn> haha
[16:36] <SpeedEvil> Hmm.
[16:38] <DRebellion> ok ALIEN it is ;P
[16:39] <hallam> sounds good
[16:40] <hallam> Nova 10 looked like a real UFO on launch
[16:40] <hallam> it was bizarre
[16:40] <hallam> the rippling orange fabric in the sun looked like it was on fire
[16:43] <Tigga_> it was awesome
[16:43] <Tigga_> need to update the website with photos + vids
[16:43] <Laurenceb> sounds cool
[16:43] <Tigga_> ah
[16:44] <Tigga_> it's been done
[16:44] <Laurenceb> I'll take a look sat the vid
[16:44] <Tigga_> http://www.srcf.ucam.org/~cuspaceflight/media.php
[16:44] <DRebellion> Well, we're going for some flashing LEDs and buzzing noises to aid recovery... so that will look good if it gets to night ; )
[16:45] <hallam> DRebellion: definitely make it very obviously Not A Bomb, signs saying "harmless experiment" in big letters etc
[16:45] <DRebellion> Will do :D
[16:45] <hallam> that's important anyway, but especially if it's flashing a\nd buzzing
[16:45] <Laurenceb> yeah thats what we usually do
[16:45] <Laurenceb> hey like the photos
[16:47] <Tigga_> we've got to be careful
[16:47] <Tigga_> 'cos terrorists might start putting "not a bomb" on their bombs
[16:48] <Laurenceb> harmless experiment
[16:51] <DRebellion> Hmm... might put a sign: "WARNING DO NOT OPEN: Danger of electrocution"
[16:51] <DRebellion> to fend off ebay fanatics
[16:51] <hallam> no, you really should avoid anything that gives the impression of any kind of danger
[16:51] <hallam> "please do not touch" will suffice
[16:51] <SpeedEvil> with a mobile number on too
[16:52] <DRebellion> Maybe the public are kinder than I imagine....
[16:52] <hallam> if you want more motivation for them to leave it alone, offer a reward
[16:52] <hallam> basically it's to deal with the situation of it landing in someone's garden with kids, and them getting shirty - you want to give the impression that it's totally harmless
[16:52] <hallam> not "it could have electrocuted my kid"
[16:52] <DRebellion> sounds like good advice
[16:52] <Laurenceb> hmm 200m atmospheric layers each one has s08 average wind in x and y axes in 0.5m/s res, and the same for the first differentail in 0.25m/s resolution. Then each time I want to find the wind I take a weifhted average of the wind as calculated using the layers above and below the current altitude.
[16:53] <hallam> Laurenceb: add a bigger eeprom already
[16:53] <Laurenceb> people have been amazingly ok with us in our experience
[16:53] <Laurenceb> hehe
[16:53] <Laurenceb> I want to use the onboard eeprom
[16:53] <DRebellion> Laurenceb, are you part of that cambridge uni team with their live landing predictions?
[16:53] <Laurenceb> incase anything goes wrong
[16:53] <Laurenceb> no
[16:53] <SpeedEvil> also - have a couple of long poles so you can dislodge from trees
[16:53] <Laurenceb> but I'll help you with code if you want :P
[16:54] <Laurenceb> DRebellion: one guy even posted me a payload back that landed in his garden
[16:54] <DRebellion> wow
[16:55] <hallam> DRebellion: you can use the CU Spaceflight predictor here: http://www.cuspaceflight.co.uk/predict/
[16:56] <Laurenceb> hmm not sure whats best.... change in position or gps velocity
[16:56] <hallam> it's also usually possible to use our launch site with semi-permanent CAA permission, radio gear and free helium
[16:56] <Laurenceb> - for wind speed calculation on ascent
[16:57] <DRebellion> hallam, that sounds great!
[16:58] <Laurenceb> position is vulnerable to constellation changes, velocity to payload spinning/moving chaotically in the slipstream of the balloon
[16:58] <DRebellion> hallam, we haven't actually got any radio ground equipment, so would the university be willing to lend us some do you think?
[16:59] <Laurenceb> SpeedEvil: I found nylon cord + a rock works well for trees
[16:59] <SpeedEvil> chainsaw!
[17:00] <Laurenceb> haha
[17:00] <Laurenceb> of course something for it to land on help as well
[17:00] <Laurenceb> so it doesnt end up completely smashed like mine
[17:01] <hallam> CUSF is separate from the university, but probably yes - at least on launch day
[17:01] <hallam> unless you use a very well-proven design, you'll want to test your radio transmitter on the ground beforehand though
[17:01] <hallam> so it's worth trying to find someone local with a scanner you can borrow
[17:01] <Laurenceb> erm I'd say always test the radio :P
[17:01] <Laurenceb> even when you do it doesnt always work after the coxon kilomemter
[17:02] <Laurenceb> ooh PBH3 recovered
[17:02] <Laurenceb> as I found
[17:02] <aLeXBrEtOn> guys, is 90k feet a reasonable altitude?
[17:02] <Laurenceb> certainly is
[17:02] <aLeXBrEtOn> for a 1200 g balloon
[17:02] <aLeXBrEtOn> OK thx ;)
[17:02] <Laurenceb> 125k is the record IIRC
[17:02] <DRebellion> aLeXBrEtOn, METRIC
[17:02] <aLeXBrEtOn> saving the wiki now ;)
[17:02] <DRebellion> -.-
[17:02] <aLeXBrEtOn> guys, metric or imperial?
[17:03] <DRebellion> 1200g refers to the weight of the latex, or the intended payload?
[17:03] <Laurenceb> what for?
[17:03] <DRebellion> the latex right?
[17:03] <Laurenceb> yes
[17:03] <aLeXBrEtOn> altitude is traditionally done in feet right?
[17:03] <Laurenceb> yes
[17:03] <aLeXBrEtOn> not km
[17:03] <Laurenceb> well we tend to use km
[17:03] <aLeXBrEtOn> OK
[17:03] <aLeXBrEtOn> lol
[17:03] <Laurenceb> but theres lots of americans
[17:03] <DRebellion> aLeXBrEtOn, yes but we do physics and physicists use SI ie. metres
[17:03] <Laurenceb> using feet :P
[17:03] <Laurenceb> yeah feet sucks
[17:03] <jcoxon> also gps report in m
[17:03] <aLeXBrEtOn> arguable
[17:04] <aLeXBrEtOn> we could be doing aviation
[17:04] <DRebellion> aLeXBrEtOn, ....
[17:04] <aLeXBrEtOn> and aviators use feet ;)
[17:04] <DRebellion> aLeXBrEtOn, we could be european
[17:04] <DRebellion> well
[17:04] <DRebellion> british
[17:04] <aLeXBrEtOn> I PUT both
[17:04] <DRebellion> i guess that doesn't count
[17:04] <DRebellion> ; P
[17:04] <aLeXBrEtOn> so calm down
[17:04] <Laurenceb> we could be siensible
[17:04] <DRebellion> Laurenceb, +1
[17:04] <Laurenceb> *sensible
[17:05] <DRebellion> aLeXBrEtOn, the wiki page is looking a bit scarce...;
[17:05] <hallam> DRebellion: after a year or two in engineering you have to become pretty fluent with both unit systems
[17:05] <aLeXBrEtOn> saved ;)
[17:05] <DRebellion> : )
[17:06] Action: DRebellion bashes aLeXBrEtOn's words into structured format
[17:06] <aLeXBrEtOn> ahem
[17:06] <aLeXBrEtOn> are you insulting the few formatting skills I have?
[17:07] <Laurenceb> I'm near Reading, so i could come over and give you a hand some tiime if you need it
[17:07] <DRebellion> Laurenceb, great :)
[17:07] <DRebellion> aLeXBrEtOn, we'll have to get the word round school somehow. I'm certain somebody will be HAM
[17:07] <aLeXBrEtOn> dude where have you put this page?
[17:08] <aLeXBrEtOn> it's not in projects
[17:08] <hallam> DRebellion: even if you don't have any hams at school, there should be a local ham group who can probably let you use their kit for some tests
[17:08] <Laurenceb> http://wiki.ukhas.org.uk/projects:alien
[17:08] <fergusnoble> Nova 10 data on the wiki
[17:08] <DRebellion> aLeXBrEtOn, link it from the main page
[17:09] <hallam> thanks fergusnoble
[17:09] <DRebellion> aLeXBrEtOn, we might as well start referring to the project as ALIEN-1
[17:09] <fergusnoble> http://www.srcf.ucam.org/~cuspaceflight/wiki/doku.php?id=nova_10
[17:09] <aLeXBrEtOn> you have to link it
[17:09] <aLeXBrEtOn> says you put an edit lock on it
[17:09] <fergusnoble> tried to get matplotlib to put proper times on the x axis
[17:09] <fergusnoble> but no joy
[17:10] <aLeXBrEtOn> shall I start filling out the application sheet?
[17:10] <hallam> fergusnoble: from that data, do you think it was indeed descending under the pilot between the first and second cutdowns?
[17:11] <hallam> http://www.mibbit.com/up/TfHNGcLx.jpg this seems to be taken just after cutdown
[17:12] <Laurenceb> neat
[17:12] <hallam> it's all orange after that
[17:12] <Laurenceb> external temp shown the tropopause nicely
[17:12] <fergusnoble> hallam: so you didnt fix the thing where it was reading out partial frames?
[17:12] <fergusnoble> :)
[17:12] <Laurenceb> sp there no stars?
[17:13] <Laurenceb> fergus: gnuplot
[17:13] <hallam> fergusnoble: did fix it but not for the auto-exposure shots (figured it didn't matter for them)
[17:13] <fergusnoble> Laurenceb: i dislike gnuplot intensely
[17:14] <fergusnoble> i have to use it for computing exercises at uni
[17:14] <Laurenceb> its awesome
[17:14] <Laurenceb> the only problem is ram use with large 3D plots
[17:14] <fergusnoble> matplotlib i find more usable
[17:15] <fergusnoble> anyway, who cares, i think there is a way to get times at the bottom, i just got bored looking for it
[17:15] <hallam> fergusnoble: I think we should have put a sunshade on it
[17:15] <hallam> but even so I think the sky was too bright
[17:15] <fergusnoble> yeah? ok
[17:15] <hallam> I don't think it's properly black at 60,000ft
[17:15] <hallam> especially at midday
[17:16] <fergusnoble> so it was just the sky being light, not bits of other things getting in the frame?
[17:16] <Laurenceb> Fergus: have you had any issues with your lassen iq?
[17:16] <fergusnoble> Laurenceb: not that i have noticed
[17:16] <hallam> don't know for sure, but I don't see evidence of other things in the auto-exposure frames
[17:16] <Laurenceb> mine refuses to get a fix
[17:16] <hallam> I'm looking at the AEC exposure values, they're like 5 lines
[17:16] <Laurenceb> unless you wipe the ram
[17:16] <Laurenceb> fergus: you using TSIP?
[17:16] <fergusnoble> hallam: ok, thats odd, and when the exp is high the frame is just pure white?
[17:16] <hallam> Laurenceb: lassen iqs tend to suck in my experience, give them at least 15 mins to get a fix, and make sure there's nothing around producing EMI
[17:16] <fergusnoble> Laurenceb: yup
[17:16] <hallam> yeah
[17:17] <Laurenceb> ok
[17:17] <Laurenceb> so looks like I havent screwed up
[17:17] <Laurenceb> its just the lassen itself
[17:17] <fergusnoble> Laurenceb: ive found the lassens to be pretty solid if a bit slow at locking in the first place
[17:17] <Laurenceb> I'm using RAM so it takes about 30 seconds to get a fix
[17:17] <Laurenceb> but it never gets a fix if its been anywhere near EMI
[17:18] <Laurenceb> without having its RAM wiped afterwards
[17:18] <Laurenceb> otherwise yeah 15 minutes
[17:18] <fergusnoble> havnt tested in EMI, think the badger is fairly clean as its only running at 60mhz
[17:18] <Laurenceb> yeah its probably my laptop
[17:18] <hallam> and for EMI read "a Blackfin CPU with external memory running at 120MHz)
[17:18] <hallam> :
[17:18] <hallam> "
[17:18] <Laurenceb> also it occasionally stops producing a lock for ~10 seconds
[17:19] <Laurenceb> which seriously ascrews up my flight computer
[17:19] <Laurenceb> it has a watchdog reset each time that happens
[17:19] <Laurenceb> and the eeprom flight log gets corrupted
[17:20] <Laurenceb> the datasheet says the position is output on TSIP every second
[17:20] <fergusnoble> hallam: re the cutdown, its not in the badger log however the radio did report two cutdowns being fired
[17:20] <DRebellion> Hmm... jcoxon recommended a lassen iq to us. Is that a bad idea?
[17:20] <hallam> yeah
[17:20] <aLeXBrEtOn> ermn gents
[17:20] <Laurenceb> even if it loses lock it shouls still output the status packet
[17:20] <aLeXBrEtOn> the IQ is recommended on the wiki
[17:21] <hallam> DRebellion: Lassen isn't terrible
[17:21] <aLeXBrEtOn> why is that then?
[17:21] <fergusnoble> and if you look at the altitude graph there does seem to be a step change in gradient shortly after apogee
[17:21] <hallam> it works at altitude, which is a big plus
[17:21] <hallam> unlike many other modules
[17:21] <aLeXBrEtOn> anyone got better units?
[17:21] <Laurenceb> ublox5
[17:21] <aLeXBrEtOn> for similar price?
[17:21] <Laurenceb> but sparkfun have sold out atm
[17:21] <fergusnoble> hallam: did the ublox5 work on startracker?
[17:21] <Laurenceb> not sure, I value my sanity above the cost difference
[17:22] <fergusnoble> Laurenceb: the lassen really isnt too bad
[17:22] <hallam> no, grr, something went wrong between blackfin and exp board
[17:22] <Laurenceb> guess so
[17:22] <hallam> hence no inertial data and no gps
[17:22] <SpeedEvil> :/
[17:22] <hallam> or rather, repetition of the same data
[17:22] <fergusnoble> aLeXBrEtOn: we have flown lassen on novas 6-10 with not problems
[17:22] <Laurenceb> its this missing status packet thats bugging me
[17:22] <aLeXBrEtOn> OK then
[17:22] <Laurenceb> it could be corrupted ram
[17:22] <aLeXBrEtOn> if the lassen has no problems, we buy that
[17:22] <aLeXBrEtOn> it is easier for us to buy as well
[17:23] <aLeXBrEtOn> with a UK distributor
[17:23] <hallam> yeah it's a good bet, just be aware that it may need a while to get a fix
[17:23] <Laurenceb> for your use, itd be ok
[17:23] <aLeXBrEtOn> and even a real shop just 30 miles from here
[17:23] <Laurenceb> I need the best gps possible really
[17:23] <fergusnoble> Laurenceb: maybe your code is wrong :p
[17:23] <Laurenceb> you just want to know where you are
[17:23] <aLeXBrEtOn> OK great ;)
[17:23] <Laurenceb> fergusnoble: no, the proplem can be solved by power cuyling the lassen
[17:23] <aLeXBrEtOn> lassen is cheap and readily available
[17:24] <fergusnoble> Laurenceb: hehe, ok, that is wierd
[17:24] <Laurenceb> but you never know if itas going to occur
[17:24] <fergusnoble> are you putting it into a wierd mode?
[17:24] <Laurenceb> I put it into aibourne mode
[17:25] <Laurenceb> maybe my config packet it wrong
[17:25] <Laurenceb> *is
[17:25] DanielRichman (n=DanielRi@89.243.213.125) joined #highaltitude.
[17:25] <Laurenceb> I should email trimble maybe
[17:25] <Laurenceb> their documentation isnt clear, there are various revisions of TSIP
[17:25] <fergusnoble> hallam: shame, is it now doing that behaviour on the bench?
[17:26] <fergusnoble> or started working again?
[17:26] <Laurenceb> basically I use the status packet to check gps functionality
[17:26] <hallam> fergusnoble: haven't got the kit here to test it
[17:26] <fergusnoble> ok
[17:26] <hallam> I thought it was workign pretty well on the bench before flight
[17:26] <Laurenceb> if the gps isnt there for 4 second the watchdog times out
[17:26] <Laurenceb> as it could be a bug in the flight computer
[17:27] <Laurenceb> of course the gps upsets also cause this
[17:27] <hallam> fergusnoble: does the apparent step in descent rate correspond to a distance of 90km?
[17:27] <hallam> the thresholds were 88 and 90
[17:27] <fergusnoble> hmm, hard to check easily
[17:28] <fergusnoble> let me try
[17:28] <aLeXBrEtOn> ermn guys
[17:29] <aLeXBrEtOn> the parachutes on random aersospace don't fit in with the size chart on the wiki
[17:29] <aLeXBrEtOn> aerospace*
[17:29] <DRebellion> aLeXBrEtOn, chris is onboard
[17:29] <DRebellion> apprently
[17:30] <DRebellion> higher denominator for our finances : )
[17:30] <aLeXBrEtOn> what's he going to do?
[17:30] <DRebellion> god knows
[17:30] <DRebellion> graphic design?
[17:30] <aLeXBrEtOn> we already have money
[17:30] <aLeXBrEtOn> no
[17:30] <aLeXBrEtOn> not necessary
[17:30] <DRebellion> orly
[17:30] <aLeXBrEtOn> we have everything we need
[17:30] <DRebellion> what if we don't get the or funding
[17:30] <aLeXBrEtOn> we will
[17:30] <hallam> there's a fair amount of fudge in parachute sizing
[17:30] <aLeXBrEtOn> hmm
[17:30] <aLeXBrEtOn> yeah
[17:30] <aLeXBrEtOn> because size chart recommends a 42 inch para for a 1400g payload
[17:31] <aLeXBrEtOn> and random aerospace says 30 inch
[17:31] <Laurenceb> fergus: does your code wait foor the gops at any point?
[17:31] <DRebellion> aLeXBrEtOn, we can't really be thinking about parachute and balloon till we've got our payload
[17:31] <Laurenceb> arm typing
[17:31] <aLeXBrEtOn> it's on the list of things to buy
[17:31] <hallam> aLeXBrEtOn: it just affects the descent rate, obviously
[17:31] <hallam> the 30 inch one will fall faster
[17:31] <aLeXBrEtOn> obviously
[17:31] <DRebellion> aLeXBrEtOn, (17:31:48) sorted9: he can either have my money or ill go watch it for free
[17:31] <aLeXBrEtOn> but not dangerously fast I assume?
[17:32] <hallam> that depends to some extent on how soft it is
[17:32] <hallam> vs hard and pointy
[17:32] <Laurenceb> fergusnoble: do you wait for the gps or use dma/interrupt driven TSIP parsing?
[17:32] <aLeXBrEtOn> DRebellion: how much money is he willing to offer
[17:32] <DRebellion> aLeXBrEtOn, hah
[17:32] <DRebellion> shall i start a benefactors section?
[17:32] <hallam> typically you should aim for a descent rate less than 8m/s or so
[17:32] <fergusnoble> Laurenceb: its based on interrupts
[17:32] <aLeXBrEtOn> WAIT
[17:32] <Laurenceb> ok, same here
[17:32] <aLeXBrEtOn> first we get money from OR
[17:32] <hallam> to avoid damaging stuff
[17:33] <aLeXBrEtOn> if we don't then you set it up
[17:33] <Laurenceb> fergus: do you wait for packets at any point?
[17:33] <aLeXBrEtOn> OK thanks hallam ;)
[17:33] <Laurenceb> or just grab the latest one
[17:33] <hallam> that's still 18mph which is pretty fast, you might want to go slower than that
[17:33] <DRebellion> 20mph doesn't seem overly fast
[17:33] <hallam> and differently shaped chutes of the same diameter will have different drag coefficients
[17:33] <DRebellion> we're thinking of just a polystyrene box?
[17:33] <fergusnoble> Laurenceb: they are buffered from the serial port and then a state machine based task grabs stuff from the buffer whenever it can
[17:34] <Laurenceb> DRebellion: 20mph to the head?
[17:34] <DRebellion> Laurenceb, no to the grass : P
[17:34] <hallam> even if it's made of polystyrene it's going to hurt
[17:34] <Laurenceb> fergus: state machine inside the isr?
[17:34] <hallam> think greenhouse
[17:34] <hallam> also, think about what it will do to your payload if you want to fly again
[17:34] <DRebellion> true
[17:34] <hallam> my "8m/s" was probably a bit high
[17:34] <DRebellion> aLeXBrEtOn, best not skimp on the parachute then
[17:34] <hallam> we don't usually go above 6 at cu spaceflight
[17:34] <fergusnoble> Laurenceb: no, the irs puts the data into a fifo which is picked up by the state machine
[17:34] <aLeXBrEtOn> is 30 inches enough?
[17:35] <fergusnoble> which is running in a tnkernel task
[17:35] <Laurenceb> ok
[17:35] <aLeXBrEtOn> that said we don't know the weight
[17:35] <DRebellion> aLeXBrEtOn, depends on the weight doesn't it
[17:35] <hallam> and on the style of the chute
[17:35] <aLeXBrEtOn> We'll see
[17:35] <DRebellion> aLeXBrEtOn, we could start compiling an estimated weight
[17:35] <hallam> if it's a "parasheet" the effective diameter is smaller
[17:35] <aLeXBrEtOn> first we buy components
[17:35] <Laurenceb> so if your gps stops outputting packets... your task just waits?
[17:35] <hallam> 1.5kg isn't bad for a first estimate
[17:35] <DRebellion> i'm sure we can get datasheets for all components before buying
[17:35] <Laurenceb> - goes to idle?
[17:35] <hallam> heaviest bits are box, camera, batteries, flight computer
[17:35] <fergusnoble> Laurenceb: the task is idle until there is data in the fifo, then the os kicks it into life
[17:36] <hallam> dont' bother weighing individual resistors, get an estimate for the whole PCB
[17:36] <Laurenceb> ah right
[17:36] <Laurenceb> fergus: so what happens if theres no packet for ~6 to 8 seconds?
[17:37] <fergusnoble> then other tasks run
[17:37] <DRebellion> hallam, thanks, we'll look up the specs for our items then
[17:37] <fergusnoble> it wont take down the whole flight computer if the gps hangs
[17:37] <Laurenceb> the main code... how does it get the gps data?
[17:37] <Laurenceb> yeah
[17:37] <fergusnoble> you can read it on the svn iuw
[17:37] <fergusnoble> but there is just an interrupt which writes into a fifo
[17:38] <hallam> to get descent rate, solve (1/2)rho * v^2 * Cd * A = W
[17:38] <hallam> where W is payload weight (in newtons)
[17:38] <Laurenceb> it uses a mailbox or something?
[17:38] <hallam> rho is atmospheric density at sea level, 1.2kg/m^3
[17:38] <fergusnoble> its a special tnkernel fifo which when accessed will block the task until it has some data, letting other tasks run
[17:39] <Laurenceb> ah right
[17:39] <hallam> Cd is drag coefficient, about 0.85 for a parasheet or 1.1 for a parachute (you should check those numbers, I just pulled them out my ass)
[17:39] <hallam> A is the area of the parachute
[17:39] <Laurenceb> so you wouldnt notice if the gps hung for a few seconds?
[17:39] <hallam> v is the velocity, m/s
[17:40] <Laurenceb> how often do you log position?
[17:40] <Laurenceb> on the SD?
[17:43] <jcoxon> Laurenceb, can i ask you a q about steve's mfsk code
[17:43] <jcoxon> how did you get line returns?
[17:43] <fergusnoble> Laurenceb: every posn packet is logged, but no i wouldnt notice if it hung
[17:43] <fergusnoble> although i could check for longer gaps between packets
[17:44] <Laurenceb> jcoxon: I didnt
[17:44] <jcoxon> oh okay
[17:44] <Laurenceb> fergusnoble: http://www.trimble.com/embeddedsystems/copernicus_support.asp?Nav=Collection-44755
[17:44] <Laurenceb> jcoxon: my php code doesnt care about lines
[17:44] <jcoxon> so it was decoded in a long line and you split it up from there?
[17:44] <Laurenceb> it reads the entire file as a string
[17:44] <Laurenceb> then searches for packets
[17:45] <fergusnoble> Laurenceb: i would have noticed if it hung for any serious amount of time
[17:45] <Laurenceb> fergusnobleI: I'm going to try that
[17:45] <Laurenceb> <8 seconds
[17:45] <fergusnoble> i have never noticed holes in any of my graphs
[17:45] <Laurenceb> hmm
[17:45] <fergusnoble> ok, give it a go
[17:45] <Laurenceb> apparently you can update the firmware
[17:46] <Laurenceb> I'd have to make a cable to connect it to my pc
[17:46] <hallam> try changing random bits until the COCOM restrictions are removed
[17:46] <Laurenceb> haha
[17:47] <Laurenceb> you could try dissasembling
[17:47] <Laurenceb> I know the processos and I think theres an assembler avaliable
[17:48] <hallam> I think the SiRF modules have ARM7 cores
[17:51] <Laurenceb> yeah trimble is an epsom E7 or soemthing
[17:51] <Laurenceb> theres gcc for it
[17:51] bfirsh (n=ben@81.2.121.150) left irc:
[17:53] <Laurenceb> hmm "The user needs to detach the power supply from the Lassen iQ module for at least 30 seconds to clear BBRAM"
[17:54] <Laurenceb> I was using ~15 seconds to clear up the issues with dodgy ram, maybe that explains some of the issues
[17:54] <Laurenceb> anyway, http://www.roundsolutions.com/techdocs/index.php#firmware
[17:55] <Laurenceb> thats from 2005, so my module should have the same firmware, but apparently it may have been corrupted - I'm just reading the sparkfun forum
[17:57] <Laurenceb> guess my first step should be to use that trimble configuration application together with a serial port spy to check the configuration packet for airbourne mode
[18:07] <aLeXBrEtOn> guys, anyone know where we can buy radiosondes?
[18:07] <aLeXBrEtOn> or temperature sensors to put on a balloon
[18:07] <fergusnoble> hallam: still there?
[18:08] <hallam> yes
[18:08] <Laurenceb> http://surreylunarrover.wordpress.com/
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[18:08] <hallam> aLeXBrEtOn: you can get ex-met-office radiosondes on ebay sometimes, but I'm not sure you're allowed to actually use them because the radio frequencies are licensed
[18:08] <fergusnoble> there is some evidence that the change in gradient happened shortly after the second cutdown fired
[18:09] <aLeXBrEtOn> hmmm
[18:09] <hallam> cool
[18:09] <hallam> as for a temperature sensor, the DS18S20 is nice, and there are a ton of others
[18:09] <fergusnoble> looks like the gradient change is about 40s after the firing command
[18:10] <hallam> ok
[18:10] <hallam> we probably ought to work out what descent rate we'd expect under just the pilot
[18:11] <fergusnoble> actually its hard to tell exactly where the change is
[18:11] Hiena (n=Hiena@81.93.195.181.datatrans.hu) joined #highaltitude.
[18:11] <fergusnoble> it could be as little as 20sec
[18:11] <fergusnoble> which would be more in line with what we would expect
[18:11] amarigonal (n=amar@calibre.demon.co.uk) joined #highaltitude.
[18:11] <hallam> right
[18:11] <Hiena> 'evening!
[18:11] <amarigonal> hi
[18:11] <hallam> hi
[18:11] <fergusnoble> however, looking at the code it really should have been written to the log
[18:11] <hallam> fergusnoble: was the code supposed to log firing of each cutdown?
[18:11] <DRebellion> amarigonal, amar!
[18:12] <amarigonal> really
[18:12] <amarigonal> its daniel
[18:12] <DanielRichman> DRebellion, I win cookie?
[18:12] <amarigonal> remote desktop
[18:12] <DRebellion> k
[18:12] <DRebellion> btw guys
[18:12] <hallam> fergusnoble: weird. It was definitely in the telemetry
[18:12] <fergusnoble> yeah
[18:12] <amarigonal> ok
[18:12] <DanielRichman> reverse remote desktop, i'll have you know. Anyway, its proprietary gfx and desktop cube time, so brb for a bit ;)
[18:12] <DRebellion> /j #rsha (reading school high altitude)
[18:13] <Laurenceb> desktop cube?
[18:13] <Laurenceb> bah its almost as gay as mac
[18:15] <DRebellion> Laurenceb, meh, it's great for coursework-evasion
[18:15] <DRebellion> also, wobbly windows ftw
[18:15] <Laurenceb> wobbly windows
[18:15] <DanielRichman> sucks
[18:15] <Laurenceb> haha
[18:15] <DRebellion> -,-
[18:15] <DanielRichman> I hate desktop cube and wobbly windows
[18:15] <DRebellion> they hate you too
[18:15] <DanielRichman> but hey, amar wants to try it out
[18:15] <Laurenceb> thyey sometimes oscillate out of control
[18:15] <DRebellion> Laurenceb, really?
[18:15] <DRebellion> never had that happen
[18:16] <Laurenceb> I've dont it on several machines
[18:16] <Laurenceb> *done
[18:17] Action: DRebellion attempts to make xchat have a spasm
[18:17] Action: DRebellion fails
[18:18] <Laurenceb> you need to turn on the clinginess
[18:18] <Laurenceb> or whatever its called
[18:18] <DRebellion> oh right, you mean cling to edges?
[18:19] <Laurenceb> yes
[18:20] <DRebellion> Would somebody with admin rights on the wiki mind linking projects:alien to the main page?
[18:22] amarigonal (n=amar@calibre.demon.co.uk) left irc: Remote closed the connection
[18:27] <jcoxon> DRebellion, done
[18:27] <DRebellion> jcoxon, thanks a bunch
[18:27] <Hiena> Ahhh, spicy taste of the peroxide... Ireally should have to label the bottles in my room...
[18:27] <DRebellion> 0_o
[18:28] Action: Laurenceb once drang nitric acid
[18:29] <hallam> spicy
[18:29] <hallam> fuming?
[18:29] <Hiena> Missed the lemon, so now i'm drinking a rather bleached tea.
[18:29] <Laurenceb> no it was from the school labs
[18:29] <Laurenceb> I filled my bag with bottles of the stuff for making guncotton, then forgot it wasnt water and drank some
[18:30] <Hiena> Heh, i had a perion when i drank my tea with muriatic acid.
[18:30] <Hiena> -n+d
[18:31] <Hiena> Laurenceb, how yellow was your mouth after that?
[18:31] <Laurenceb> not very, but it stung a lot
[18:32] <hallam> I heard about a guy at my school who made guncotton in lab, put it in his pockets while it was still damp and ended up nitrating his trousers
[18:32] <Hiena> Ususally after the nitrification process i ends up with yellow hands.
[18:34] <Hiena> My modeller pals usually could foretell, how much rocket i brought to the field, simply seeing my hands.
[18:34] <Laurenceb> hehe
[18:34] <Laurenceb> right I'm off
[18:34] <Laurenceb> cya guys
[18:35] <Hiena> Have fun!
[18:35] <hallam> bye
[18:35] Laurenceb (i=83e34f19@gateway/web/ajax/mibbit.com/x-b0911f2f3586f77f) left irc: "http://www.mibbit.com ajax IRC Client"
[18:36] <aLeXBrEtOn> can anyone here recommend me a pressure sensor?
[18:38] <Hiena> Anlogue or digital? whats resoulution? Temperature compensated or not?
[18:38] <aLeXBrEtOn> no temperature
[18:38] <Hiena> Cheap or expensive?
[18:38] <aLeXBrEtOn> to fit on an Arduino
[18:38] <aLeXBrEtOn> in the weather balloon
[18:38] <aLeXBrEtOn> preferably cheap ;)
[18:39] <hallam> SCP1000 breakout board from Sparkfun
[18:39] <hallam> it's not that cheap
[18:39] <Hiena> Well, i used the temperature compensated MPX series absolute pressure sensor.
[18:40] <Hiena> It's round 4500 HUF, which is around 15 EUR.
[18:40] <DRebellion> that's not bad
[18:40] <Hiena> aLeXBrEtOn, do you want to use it for HAB?
[18:41] <aLeXBrEtOn> yes
[18:41] <DRebellion> Could we get a combined temperature and pressure then?
[18:41] <DRebellion> No point having multiple temp sensors
[18:42] <Hiena> Nope. The temperature compensation means the pressure sensor has no drift on the output from the temperature change.
[18:43] <DRebellion> Hiena, not sure I follow?
[18:44] <Hiena> These sensors usually contains several temperature sensitive parts. As the sensor cools down, an error adds to the output signal.
[18:44] <hallam> Hiena: it doesn't separately output an absolute temperature, then? many temp-compensated sensors do, which is convenient
[18:45] <hallam> I know the SCP1000 does
[18:47] <Hiena> For example the uncompensated sensor says 1015m at 20 degree celsius, if you cools it down to zero degree sensor will says 850m. The compensation part change the voltage of the sensor correcting the teperature drift.
[18:48] <Hiena> Some sensors has extra output from the temperature sensor inside the the pressure sensor, some hasn't.
[18:48] <DRebellion> What are the options for GSM? How cheaply could we implement a system?
[18:49] <Hiena> If you use uncompensated sensor, you have to do the calculation for the compensation, but it will contains errors.
[18:49] <Hiena> DRebellion, depends on, how cheap you could buy a parts for the relay tower.
[18:49] <hallam> hah
[18:50] <DRebellion> Hiena, this is really just as a landing solution
[18:50] <DRebellion> We're currently planning GPS via radio for high altitude
[18:50] <DRebellion> But the convenience of a GPS SMS would be astounding
[18:50] <hallam> DRebellion: the cheapest method involves getting a free phone from someone, and annoying yourself trying to connect it to the arduino
[18:50] <DRebellion> hallam, i have a nokia 3220
[18:50] <Hiena> The GSM boards around 40 EUR here. So i rather wote for the used mobile.
[18:50] <DRebellion> would that do?
[18:51] <jcoxon> DRebellion, there is an AT command lib for ardiunos
[18:51] <DRebellion> jcoxon, what is AT?
[18:51] <Hiena> DRebellion, the 3210, 5110 is good for the hack. Both could be activated with the ATX command through a 9600 baud serial line.
[18:52] <hallam> I didn't think the 3210 supported AT commands?
[18:52] <hallam> but you could still use FBUS or MBUS
[18:52] <jcoxon> nor does the 5110
[18:52] <jcoxon> At commands are a method of communicating
[18:52] <jcoxon> its a serial link and you send specific commands
[18:53] <Hiena> 5110 works fine. Ibuilt several remote sensor unit around that phone.
[18:53] <DRebellion> jcoxon, sounds simple enough
[18:53] <Hiena> Even the 5110 has a built in 56K modem.
[18:53] <hallam> nice
[18:54] <hallam> the older Nokias don't have modems or do AT commands though
[18:54] <hallam> you can still use them to send SMS, but you have to use FBUS or MBUS, which are really annoying in my experience
[18:54] <hallam> worth seeing if someone's written arduino code to do it already
[18:54] <Hiena> Check the gnokii source.
[18:54] <hallam> http://www.uelectronics.info/nokia-fbus
[18:55] <jcoxon> damn
[18:55] Action: jcoxon kicks zeusbot for being slo
[18:55] <jcoxon> w
[18:55] <jcoxon> i give up :-)
[18:56] <Hiena> Well, i'm off to fiddle with a GPS telemetry timings.
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[19:05] <Laurenceb> hello again
[19:05] aLeXBrEtOn (n=Alexande@client-80-5-40-149.cht-bng-014.adsl.virginmedia.net) joined #highaltitude.
[19:11] <aLeXBrEtOn> can anyone advise me on what angles the camera will be at?
[19:11] <aLeXBrEtOn> I assume sideways, sorta downwards
[19:12] <hallam> yeah that's about right
[19:12] <aLeXBrEtOn> no exact setting I guess
[19:12] <hallam> not too far downwards, since you usually want to see the horizon
[19:12] <hallam> you know about CHDK, right?
[19:13] <aLeXBrEtOn> about 100 degrees from vertical?
[19:14] <Laurenceb> sounds about right
[19:14] <Laurenceb> you could test
[19:14] <Laurenceb> by handing your payload and taking shots
[19:14] <hallam> that angle should be about right
[19:14] <Laurenceb> *hanging
[19:14] <hallam> don't worry about it too much, the swinging will ensure you get a variety of shots
[19:15] <aLeXBrEtOn> hmm
[19:15] <aLeXBrEtOn> CHDK exists for all Canon cameras, right?
[19:15] <hallam> most
[19:15] <hallam> it's pretty good
[19:15] <hallam> just wanted to be sure you were aware of its existence, so you don't have to go hacking at your camera's shutter button
[19:16] <aLeXBrEtOn> can't seem to find for A80
[19:16] <Laurenceb> some of us have used cheap cameras e.g. premier
[19:16] <Laurenceb> to get the price down
[19:16] <aLeXBrEtOn> does it use the same one as A70?
[19:16] <hallam> prolly, give it a try
[19:16] <hallam> I don't actually know much about CHDK
[19:16] <aLeXBrEtOn> ok
[19:18] <aLeXBrEtOn> ermmmm
[19:18] <jcoxon> chdk doesn't work on A80s or A70s
[19:18] <aLeXBrEtOn> aye that's what I was coming to
[19:18] <aLeXBrEtOn> is it really necessary?
[19:18] <aLeXBrEtOn> for High-alt photos?
[19:19] <jcoxon> quality is worthwhile
[19:19] <Laurenceb> you can hack the shutter
[19:19] <aLeXBrEtOn> ok..
[19:20] <hallam> oh, pity
[19:20] <hallam> chdk is very convenient but if you already have the camera and don't want to buy another, sure, hack the shutter
[19:20] <aLeXBrEtOn> thanks ;)
[19:21] <aLeXBrEtOn> we haven't worked out the details of getting the camera to fire when we want
[19:21] <Laurenceb> if oyu do it neatly you can still have a useable camera
[19:26] <Laurenceb> e.g. epoxy a little socket into the side
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[19:44] <DRebellion> jcoxon, you recommended this transmitter http://www.radiometrix.co.uk/products/ntx2nrx2.htm earlier, but the page says it only goes down to -10*C
[19:44] <Laurenceb> its worked ok
[19:44] <Laurenceb> just keep it warm with some foam
[19:45] <DRebellion> How warm can we expect the payload to be inside? Considering we're planning to use some polystyrene blocks as the walls?
[19:47] <Laurenceb> use thermal resistivity :P
[19:47] <DRebellion> =/
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[19:48] <rjharrison_> DRebellion: probably about 10 - 0 deg c
[19:48] <DRebellion> rjharrison_, wow
[19:48] <rjharrison_> depending on your heat decipation
[19:49] <rjharrison_> If you have a camera onboard and sealed unit then quite warm
[19:49] <rjharrison_> gets a bit colder on the way down
[19:49] <hallam> DRebellion: the NTX2 is definitely the most popular transmitter in the UK
[19:49] <rjharrison_> the radiometrix modules have a good track record so far
[19:49] <G8KHW> Live update kmz of airtraffic over holland, north sea and some of the uk :- http://www.gearthhacks.com/downloads/go.php?file=29681
[19:50] <DRebellion> OK, fair enough guys
[19:50] <DanielRichman> rjharrison_, you mention having a camera onboard & sealed unit - does that mean, the camera has to be inside the same box to get its heat?
[19:50] <hallam> G8KHW, very cool
[19:51] <hallam> DanielRichman: it's usually not a perfect seal
[19:51] <hallam> but typically yes the camera will be in the box with a porthole cut out to see through
[19:51] <DanielRichman> hallam, Ok
[19:51] <Laurenceb> delta_t=power_diss*thermal*res*wall_thickness/wall_area
[19:51] <Laurenceb> if you seal it well
[19:52] <Laurenceb> delta_t=power_diss*thermal_resisitivity*wall_thickness/wall_area
[19:52] <hallam> you can put it outside and take your chances with the cold, it'll probably be ok since the camera body itself provides some insulation and it generates its own internal heat, but they're not designed for these conditions
[19:52] <hallam> I think CUSF have had a few flights with cameras outside with varying degrees of success
[19:52] <DanielRichman> hallam, If it goes outside I guess it could have its own lump of foam/box of polystryrene
[19:52] <hallam> if you can get hold of a UV filter that will improve the photos quite a bit
[19:52] <Laurenceb> power_diss=battery_voltage*current_consumption
[19:53] <DanielRichman> hallam, But also, I guess if that you put the camera inside then it will warm up the rest of the circuitry, which may be required to keep the transmitter at a good temp.
[19:54] <hallam> sure
[19:54] <hallam> the basic effect of temperature on the transmitter is that the carrier frequency will change, or "drift"
[19:54] <hallam> the NTX2 have less drift than some other modules we've tried
[19:54] <hallam> but you still have to retune the receiver a bit
[19:56] <DanielRichman> Not too much of a problem then
[19:56] <DRebellion> Where can we buy the ntx2 then?
[19:56] <hallam> yeah
[19:56] <hallam> direct from Radiometrix
[19:57] <hallam> they take credit cards over the phone
[19:57] <hallam> or debit
[19:57] <DRebellion> cool
[19:57] <hallam> I think Farnell sells them at some unpleasant markup
[19:58] <hallam> beware circuit boards built with cheap ceramic capacitors (Z5U or Y5V)
[19:58] <hallam> those really change dramatically in value below about -20C
[19:58] <DRebellion> hallam, we'll stick to whatever #highaltitude recommends ;)
[19:59] <DanielRichman> DRebellion, will have to doublecheck the components on the arduino we get
[19:59] <DRebellion> DanielRichman, indeed
[19:59] <DanielRichman> we can always shove it in a fridge for a day for funz
[19:59] <DRebellion> I'm sure #highaltitude has interfaced some storage with an arduino?
[19:59] <hallam> most other electronic parts tend to be good down to stratosphere temperatures (~ -50C) even if the datasheet for the whole module doesn't spec it that low
[19:59] <hallam> I don't actually know if anyone here has used an arduino on a HAB but my hunch is it would be fine
[19:59] <hallam> typically our electronics boxes don't get much lower than -15C
[20:00] <G8KHW> hallam: how did the cutdowns go?
[20:00] <hallam> G8KHW: wonderfully
[20:00] <DanielRichman> DRebellion, arduino storage looks like its gonna be a SD Card
[20:01] <hallam> saved the mission
[20:01] <hallam> also after having one go off in my face, all my doubts about them are removed, I totally endorse the Steve design
[20:02] <hallam> what was in them? it didn't look like BP
[20:04] <Laurenceb> C4
[20:06] <G8KHW> hallam: yeah ALWAYS wear goggles - and/or connect them up at the other end of the wire
[20:08] <hallam> well I wasn't expecting anything cutdown-related to happen, was just checking the badger on the bench
[20:09] <hallam> in retrospect I should have unplugged them first
[20:09] <G8KHW> yeah I have seen a lot of stuff go off like that (ejection charges etc)
[20:10] <hallam> what is the charge made of, if it's ok to ask?
[20:13] <G8KHW> stuff we use for ejection charges (not BP)
[20:13] <G8KHW> i'll drop U a line
[20:13] <hallam> ok
[20:13] <hallam> ta
[20:13] <G8KHW> bbl
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[20:22] <DRebellion> How much does a NTX2 cost?
[20:23] <hallam> can't remember, sorry
[20:23] <hallam> less than 30 pounds I think
[20:23] <SpeedEvil> of the order of 20 quid
[20:23] <Laurenceb> £17 IIRC
[20:23] <Laurenceb> maybe 12.50
[20:24] <DRebellion> so
[20:24] <DRebellion> between 12 and 30
[20:24] <hallam> have you checked their website?
[20:24] <DRebellion> hallam, it just says call them
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[20:25] <DRebellion> jcoxon, any idea how much an ntx2 would cost?
[20:25] <hallam> ok
[20:25] <hallam> 20 sounds about right to me
[20:25] <DRebellion> ok
[20:25] <Laurenceb> arg whod think the atmodphere was so turbulent :P
[20:25] <SpeedEvil> damn windy out
[20:25] <hallam> http://uk.farnell.com/radiometrix/ntx2-434-650-10/transmitter-434-65mhz-10mw/dp/1348829
[20:26] <jcoxon> if you can get the 434.075 module its prefered
[20:26] <hallam> 17 + vat, and they're almost certainly cheaper direct from the manufacturer
[20:26] <Laurenceb> I'm guess ing it was 12
[20:26] <hallam> jcoxon: why? I thought that repeater was on 650
[20:26] <hallam> er, 075
[20:26] <jcoxon> no its on .650
[20:26] <DRebellion> jcoxon, why is that?
[20:26] <G8KHW> humm - can anyone explain this PIC C omplier problem - I have a local include file which I want to put some function prototypes in - if the file is empty or includes /* */ comments everything is ok - but if it includes anything else (including // type comments) it fails with a syntax erroro
[20:26] <jcoxon> as HAM repeaters are sometimes on 434.650
[20:27] <hallam> oops
[20:27] <Laurenceb> G8KHW: // is C99
[20:27] <Laurenceb> /* is C98
[20:27] <Laurenceb> erm 89
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[20:27] <hallam> G8KHW: is that the official Microchip compiler or another one?
[20:27] <Laurenceb> your compiler is old :P
[20:27] <G8KHW> microchip c18
[20:28] <hallam> I've definitely used // with that, so it's not that
[20:28] <hallam> some problem with the code that #includes it?
[20:28] <hallam> missing newline at the end of the file, perhaps
[20:28] <G8KHW> the // work in the main c file - just not in the include
[20:29] <hallam> that's a bit weird
[20:29] <G8KHW> or even somthing like int ijk; fails
[20:29] <G8KHW> any bit of c fails except /* */
[20:29] <DRebellion> jcoxon, so we would want NTX2-434.075-10 ?
[20:30] <hallam> DRebellion: yes
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[20:30] <hallam> G8KHW: could you send me a copy of the code and project file? (hmh33@cam.ac.uk)
[20:31] <G8KHW> sure
[20:31] <hallam> oh, one other idea - C18 has subtle bugs under 64-bit windows
[20:31] <hallam> the preprocessor in particular
[20:33] <Laurenceb> if I want to fit a line y=m*x+c to some data, c = the average and m = the average change between datapoints?
[20:33] <Laurenceb> is that an ok way to do it?
[20:33] <Laurenceb> (yes its a dumb question)
[20:33] <DRebellion> The internets are not providing any information about hacking my nokia 3220 ; (
[20:33] <hallam> c should be correct, but I don't think m is
[20:33] <hallam> DRebellion: search on FBUS or MBUS instead, they're more generic and will work
[20:34] <DRebellion> hallam, will do
[20:34] <Laurenceb> yeah, m confused me...
[20:34] <hallam> Laurenceb: look up linear regression
[20:34] <Laurenceb> am doing
[20:34] <Laurenceb> grr I should know this :(
[20:34] <hallam> the nice / general way to do it is by gaussian elimination
[20:34] <hallam> you're finding the least-squares solution to an overdetermined matrix equation
[20:34] <hallam> 1 line of matlab does it, and 2 lines gives you the uncertainties in m and c
[20:35] <Laurenceb> yeah but this has to run on a micro
[20:36] <hallam> can still be done
[20:36] <hallam> there's a simple formula for this case
[20:36] <G8KHW> hallam: file sent
[20:36] <hallam> brb, dinner
[20:36] Nick change: hallam -> hallam|food
[20:36] <DRebellion> There are five circular flat metal connectors under the battery
[20:36] <DRebellion> is that mbus or fbus
[20:36] <DRebellion> or either?
[20:37] <G8KHW> nokia - both
[20:37] <G8KHW> IIR
[20:37] <DRebellion> G8KHW, thx
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[20:42] <DRebellion> G8KHW, this guide is claiming four pads? http://www.embedtronics.com/nokia/fbus.html#part1
[20:47] <G8KHW> yeah - thats the one i used to get it going
[20:48] <DRebellion> G8KHW, then why have i got five?
[20:48] <G8KHW> don know - different phone to me
[20:49] <DRebellion> ; (
[20:49] <G8KHW> i use 3210 and 3410 methinks
[20:49] <DRebellion> G8KHW, know any other sources of information on fbus?
[20:49] <jcoxon> i sometimes think its worth the extra effort to find an AT compatible phone
[20:49] <jcoxon> it soo much easier
[20:49] <DRebellion> jcoxon, perhaps you're right
[20:49] <DRebellion> i can't find _anything_
[20:49] <jcoxon> i personally use a GM862
[20:51] <DRebellion> jcoxon, any particular model?
[20:52] <jcoxon> oh AT compatible phone?
[20:52] <jcoxon> of*
[20:52] <jcoxon> not sure
[20:52] <jcoxon> i think some ericsons work
[20:56] <DRebellion> What does AT stand for?
[20:59] <fergusnoble> from AT&T, but in reference to the modem protocol used by AT&T modems where every command started with an "AT"
[20:59] <Hiena> Jup.
[20:59] <Hiena> kind of standard for the modem communication.
[21:00] <DRebellion> right
[21:01] <Hiena> Basically these are the codes, which allows to configure your device.
[21:01] Nick change: hallam|food -> hallam
[21:01] <hallam> G8KHW: yup, you need a newline at the end of the .h file
[21:02] <Laurenceb> hmm how do I fit a polynomial in octave?
[21:02] <hallam> polyfit if it's supposed to be matlab-compatible
[21:02] <Laurenceb> polyfit appears to do something... but what
[21:02] <hallam> DRebellion: look up your phone on pinouts.ru
[21:02] <Laurenceb> pp=polyfit(average_winds(1,[1:340])',average_winds(2,[1:340])',8)
[21:02] <Laurenceb> warning: dgelsd: rank deficient 340x9 matrix, rank = 4
[21:02] <hallam> different phones have different pads, but fbus and mbus should work if you can figure out which pad's which
[21:03] <hallam> what do you get in pp after that?
[21:03] <Laurenceb> 1x9 matrix
[21:03] <hallam> hm, that's odd
[21:03] <hallam> it's just 2d data?
[21:03] <Laurenceb> yes
[21:04] <Laurenceb> x and y velocities
[21:04] <DRebellion> hallam, http://pinouts.ru/CellularPhones-Nokia/nokia_5140_pinout.shtml
[21:04] <hallam> so average_winds(1,:) is x and (2,:) is y?
[21:04] <DRebellion> gotcha!
[21:04] <DRebellion> thanks a bunch
[21:04] <Laurenceb> yep
[21:05] <hallam> DRebellion: wire-wrap wire (also known as kynar wire) is great for soldering to those hard-to-reach pads, and for being thin enough to get out of the case under the battery
[21:05] <hallam> you can order it online, it's very useful to have around
[21:06] <DRebellion> : O
[21:06] <DRebellion> http://upload.wikimedia.org/wikipedia/commons/2/23/PDP-8I-backplane.jpg
[21:06] <hallam> Laurenceb: and they're in increasing order of time?
[21:06] <natrium_> fergusnoble, AT == ATtention
[21:06] <Laurenceb> hallam: yes
[21:06] <Laurenceb> - actually altitude
[21:06] <G8KHW> hallam: thanks - that wasn't the original problem (just a drop off by me) - but the original problem has bow gone - i suspect the main file had a control char in it just befire the include which I removed
[21:06] <Laurenceb> they are altitude bins
[21:06] <G8KHW> bow = now
[21:07] <hallam> it
[21:07] <hallam> it's a bit weird, I can't see how it *ought* to need a newline, but there you go
[21:08] <hallam> Laurenceb: what you're trying to do at the moment is fit x-velocity against y-velocity
[21:08] <hallam> but you should be fitting x-velocity against altitude, and separately y-velocity against altitude
[21:08] <Laurenceb> yes
[21:08] <hallam> or better, vector velocity against altitude
[21:08] <Laurenceb> hmm yeah
[21:08] <hallam> so create an altitude vector
[21:09] <Laurenceb> ah right course
[21:11] <G8KHW> hallam: thanks that was definitly part of the problem
[21:13] <hallam> MCC18 has its idiosyncrasies - out of interest are you on win64 or 32?
[21:15] <natrium_> fergusnoble, the predictor worked great btw, very close to the actual trajectory
[21:16] <fergusnoble> oh awesome, could you post kmls for comparison if you have them?
[21:16] <fergusnoble> we are still a little short on test data
[21:16] <natrium_> hrm, i haven't saved the one from the predictor, only got a printout that i could scan in
[21:17] <Laurenceb> hallam: is polyfit supposed to work with matrices?
[21:17] <fergusnoble> natrium_: dont worry then
[21:17] <natrium_> k, next time i will save it
[21:18] <hallam> Laurenceb: I think so
[21:18] <hallam> are you sure that a polynomial is what you want, though?
[21:19] <hallam> can you send me the data as a .mat file?
[21:20] <Laurenceb> I'll try writing the wind data
[21:22] <Laurenceb> thanks, hmh33?
[21:23] <hallam> yeah
[21:23] <Laurenceb> sent
[21:24] <Laurenceb> thats at 15m intervals during the ascent
[21:25] <Laurenceb> its so noisy :-/
[21:26] <Laurenceb> I can get useable data out by taking 120m averages
[21:26] <Laurenceb> but I'm sure theres much better ways
[21:26] <Laurenceb> doing a line fit doesnt work that well
[21:28] <hallam> grr octave, this isn't a .mat file
[21:29] <Laurenceb> hmm
[21:29] <hallam> nm, I can read it, it's just a grumble
[21:29] <hallam> wow sure is noisy
[21:29] <hallam> what are the units?
[21:30] <Laurenceb> sent it again
[21:30] <Laurenceb> oh sorry
[21:30] <Laurenceb> erm rads per second
[21:30] <Laurenceb> on the earth
[21:30] <hallam> over the earth?
[21:30] <hallam> ok
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[21:30] <Laurenceb> corrected for latitude
[21:31] <hallam> and they're equally-spaced altitude bins?
[21:31] <Laurenceb> yes
[21:31] <G8KHW> hallam: win32 (vista home premium)
[21:31] <hallam> so there's just one sample for each bin, or did you already do some averaging?
[21:31] <hallam> G8KHW: ok, thanks
[21:31] <Laurenceb> theres some averaging
[21:31] <hallam> ok
[21:32] <Laurenceb> 2 to 4 samples per bin
[21:32] <Laurenceb> if I use 120m bins its good enough to maintain control
[21:33] <hallam> how big are the bins in what you sent me?
[21:33] <Laurenceb> 15m
[21:33] <SpeedEvil> Laurenceb: you've tried correlating wind going up, against wind when coming down now?
[21:33] <hallam> is the velocity from VTG or from differenced lat/lon?
[21:33] <Laurenceb> but I think theres got to be better ways - using line fits for 150m bins works quite well
[21:33] <Laurenceb> differenced lat long
[21:34] <hallam> definitely the best thing you can do is go to VTG
[21:34] <Laurenceb> I had horizontal velocity from the TSIP packets
[21:34] <Laurenceb> but wiped it by mistake :-/
[21:34] <SpeedEvil> oh
[21:34] <hallam> that will make much more difference to the quality of the data than changing your interpolation methods
[21:34] <Laurenceb> yeah
[21:34] <Laurenceb> but still, over 150m or so I should be able toget good data
[21:35] <hallam> but as for getting useful stuff from the data you have, try running a digital LPF over it
[21:35] <SpeedEvil> Laurenceb: you need a trained eagle to lift your device up a few dozen times a day.
[21:35] <hallam> with the 3dB point at about 150m altitude
[21:35] <Laurenceb> actually... ~30s per 150m bin
[21:35] <Laurenceb> 10m arror at either end
[21:35] <hallam> that'll get you data that's very slightly better than the averaging you're doing already
[21:35] <Laurenceb> ~1m/s error
[21:36] <Laurenceb> thats not very good
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[21:36] <Laurenceb> yeah using horizontal v should be better
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[21:36] <Laurenceb> pity I wiped the data
[21:39] <Laurenceb> http://imagebin.org/42537
[21:39] <Laurenceb> thats with 150m line fitting bins
[21:39] <akawaka> any pages up with info from this weekend launches?
[21:39] <Laurenceb> then weighting the two nearest bins
[21:40] <Laurenceb> easily good enough to maintain control
[21:40] <Laurenceb> but not much better than simple 120m bins
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[21:41] <hallam> akawaka: some Nova 10 pictures at http://www.cuspaceflight.co.uk/media.php
[21:41] <Laurenceb> the spikes are wind gusts, stalls, and constellation changes
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[21:43] <Laurenceb> you can hear the doppler on martlet
[21:45] <Laurenceb> what the... http://www.srcf.ucam.org/~cuspaceflight/images/nova8selected/PICT0705.JPG
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[21:46] <hallam> the author is one of our main sponsors
[21:46] <Laurenceb> neat
[21:46] <hallam> yeah he's a nice chap
[21:46] <hallam> he was at the Nova 10 launch actually (both days)
[21:47] <Laurenceb> think I saw him
[21:54] <Laurenceb> hallam: yeah, digital low pass filter appears to work as well as the line fitting technique
[21:54] <Laurenceb> theres a slight lag introduced
[21:54] <hallam> there shouldn't be a lag with post-processing
[21:54] <Laurenceb> thats the only problem
[21:55] <Laurenceb> yeah
[21:55] <hallam> make sure the kernel is centered on the current entry rather than ending on the current entry, if you see what I mean
[21:55] <Laurenceb> I know, thats whats wrong atm
[21:56] <DRebellion> Will the lack of a UV filter compromise our images?
[21:56] <hallam> depends - results vary
[21:57] <hallam> http://www.srcf.ucam.org/~cuspaceflight/media we've used a UV filter since Nova 6, I think
[21:57] <hallam> I definitely remember seeing some weird-looking photos with cheap cameras from some of the earlier launches
[21:57] <DRebellion> hallam, I'll take a look at some of the images then
[21:57] <hallam> of course we mostly just put the nice-looking photos on the web
[21:57] <hallam> nice-ish cameras might have UV filters built in?
[21:58] <aLeXBrEtOn> so gents, do we need a UV filter?
[21:58] <aLeXBrEtOn> is there that much UV up there?
[21:58] <fergusnoble> DRebellion: the main reason we used a UV filter was its about the cheapest way you can get a piece of optical quality glss
[21:58] <DRebellion> aLeXBrEtOn, see above
[21:58] <DRebellion> I don't think we'd need one
[21:58] <fergusnoble> *glass
[21:58] <aLeXBrEtOn> OK solved
[21:58] <fergusnoble> we wanted to have the camera inside the payload and a window
[21:59] <fergusnoble> the UV filter whilst also stopping uv has scratch and anti-glare coatings etc. and is more transparent than your average bit of glass
[22:00] <hallam> I think it was nova 3 and 4 that particularly had noticeable weirdness that was probably UV-induced
[22:00] <hallam> on the cheapo premier cameras IIRC
[22:00] <hallam> some of the videos are properly purple
[22:00] <DRebellion> aLeXBrEtOn, how cheap is the a80?
[22:00] <aLeXBrEtOn> pfffff
[22:00] <aLeXBrEtOn> no clue
[22:00] <DRebellion> hallam, nova 1 looks stunning though
[22:00] <hallam> if it's a canon it probably has at least vaguely decent optics
[22:00] <aLeXBrEtOn> not very ;-)
[22:01] <akawaka> should be able to get a uv filter for $30 or so
[22:01] <DRebellion> I reckon we'd be ok without one
[22:01] <aLeXBrEtOn> yeah, but it'll be from the US
[22:01] <hallam> DRebellion: yes, I'm trying to remember what camera it was, I think it was a fairly cheap kodak
[22:01] <aLeXBrEtOn> it's a mid-range camera
[22:01] <aLeXBrEtOn> the A80
[22:01] <aLeXBrEtOn> no piece of crap
[22:01] <hallam> DRebellion: I also think you'd be ok without one, but you could get one from any photography shop in the UK if you did want one
[22:01] <aLeXBrEtOn> gave faithful service for many years ;-)
[22:01] <DRebellion> aLeXBrEtOn, kudos to you for putting it up for duty
[22:01] <aLeXBrEtOn> heh my dad nearly got angry
[22:01] <DRebellion> Has anybody here successfully used a gsm sms gps system over fbus?
[22:01] <aLeXBrEtOn> 'it's my camera!'
[22:02] <DRebellion> haha
[22:02] <aLeXBrEtOn> 'you haven't used it in 5 years!'
[22:02] <natrium_> fbus?
[22:02] <DRebellion> natrium_, http://www.embedtronics.com/nokia/fbus.html
[22:02] <DRebellion> what i'm planning to do
[22:02] <DRebellion> from what i've read, its a complete pain in the arse
[22:02] <hallam> DRebellion: your sentence didn't really make sense, though
[22:02] <natrium_> DRebellion, looks like a regular UART
[22:03] <DRebellion> natrium_, yes
[22:03] <natrium_> just running at a fast baudrate 115200 baud
[22:03] <natrium_> so you'd want a fast clock on your micro
[22:03] <hallam> natrium_: that's when you have the official Nokia interface cable
[22:03] <DRebellion> planning to use an arduino
[22:04] <hallam> IIRC when you're working directly with the pins on the phone, there's something weird with the signal levels
[22:04] <hallam> could be wrong though
[22:04] <hallam> 115200 is no problem for an arduino
[22:04] <natrium_> hmm
[22:04] <natrium_> well, it could be a problem if clock is below 8MHz
[22:05] <natrium_> what does arduino use?
[22:05] <DRebellion> We're planning to use their flagship model, the duemiliso or some thing
[22:05] <hallam> 115200 is really a very standard baud rate, any microcontroller worth its salt should be able to deal with it
[22:05] Action: Laurenceb suggests PDIP uC on stripboard
[22:06] Action: hallam was trying to get 3801600 baud to work last week, which was a little trickier
[22:07] <akawaka> the diecimila routes the uart to the usb port
[22:07] <akawaka> and the software serial api only supports 9600baud
[22:07] <hallam> really? that's pretty lame
[22:08] <hallam> I guess it's MBUS for you guys
[22:08] <aLeXBrEtOn> hmmm OK guys I guess I gtg
[22:08] <aLeXBrEtOn> bye
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[22:08] <Laurenceb> bypass the api
[22:08] <hallam> or just don't use the phone, they're annoying and heavy
[22:09] <akawaka> you could disable the usb port
[22:09] <Laurenceb> http://imagebin.org/42559
[22:09] <hallam> I really don't know how to feel about the arduino, it's cool that it's very friendly and easy to use, but it's so horribly underpowered
[22:09] <akawaka> but at that point you might as well just stick an at or pic on a board
[22:09] <hallam> better than the basic stamp, at least
[22:09] <DRebellion> I think I won't bother with gsm
[22:09] <Laurenceb> blue is software lowpass, red with line fitting bins, green with wieighted 150m bins
[22:09] <DRebellion> It's going to be too much hassle
[22:10] <akawaka> its more than powerful enough for what people use it for though
[22:10] <Laurenceb> hallam: its quite powerfull
[22:10] <Laurenceb> just cripped in some respects by the api
[22:10] <akawaka> the new mega is a atmega1280
[22:10] <Laurenceb> its basically a frontend for gcc
[22:10] <natrium_> dunno why people won't use C instead :P
[22:10] <natrium_> or directly rather
[22:10] <Laurenceb> yeah
[22:11] <Laurenceb> its daft
[22:11] <akawaka> not really
[22:11] <Laurenceb> if you wnat ease of use try procyon
[22:11] <akawaka> its simple
[22:11] <Laurenceb> but thats crppling enough for me
[22:11] <akawaka> its not meant for people like you:)
[22:11] <Laurenceb> when you see whats actually be compiled its like argggggg
[22:11] <Laurenceb> hundereds of lines of junk
[22:11] <natrium_> one would assume that people who do HW would want to have every bit of control
[22:12] <natrium_> :P
[22:12] <akawaka> arduino is so people who want to feed their cats through twitter
[22:12] <Laurenceb> hallam: would you say it doesnt really matter
[22:12] <Laurenceb> - from that grpah
[22:12] <akawaka> not for ballononauts
[22:13] <akawaka> new term, use it
[22:13] <natrium_> hehe
[22:13] <Laurenceb> I'll probably go for weighted bins, nice and easy
[22:13] <natrium_> coffee is done, anybody coming?
[22:14] <akawaka> yes
[22:14] <hallam> Laurenceb: sure, go with the simple solution
[22:14] <Laurenceb> natrium:I'll have to get to the airport
[22:14] <Laurenceb> hallam: thats just a graph of velocities
[22:14] <SpeedEvil> akawaka: I've contemplated feeding my cat using webcam + 'motion' + servo
[22:14] <Laurenceb> so as long as the origion is in the center, its controllable
[22:14] <natrium_> do it, it's only a 5 hours flight :P
[22:15] <SpeedEvil> akawaka: it's annoying - as the birds eat the food - and the cat is deaf, so can't be called, and it's an outside cat.
[22:15] <hallam> 5 hours to Ontario?
[22:15] <Laurenceb> of course you want it to form a circle around the origin for it to fly well
[22:15] <Laurenceb> but that looks pretty flyable to me
[22:16] <natrium_> hallam, actually 8 hours :S
[22:16] Action: natrium_ blames the jet stream
[22:17] <hallam> tell me about it, off to Boston this week
[22:17] <hallam> 7 hours on a good day
[22:17] <natrium_> ah cool, how long are you staying there?
[22:17] <hallam> couple of weks
[22:18] <natrium_> you can attend the transatlantic launch then :D
[22:18] <hallam> heh - maybe, it's a bit of a trek but would be v. cool
[22:18] <Laurenceb> has jcoxon posted the sensor and valves?
[22:19] <hallam> where's the launch site?
[22:19] <natrium_> kitchener, ontario
[22:19] <natrium_> 900 km from boston
[22:19] <natrium_> a day's drive
[22:20] <hallam> hm, could fly up - any GA airports near you?
[22:20] <SpeedEvil> hallam: you're wings'd get tired.
[22:21] <Laurenceb> http://www.usa.denon.com/productdetails/3429.asp
[22:21] <natrium_> hallam, YKF
[22:22] <hallam> cool, I'll keep it in mind
[22:22] <natrium_> :)
[22:22] <Laurenceb> http://www.amazon.com/Denon-AKDL1-Dedicated-Link-Cable/product-reviews/B000I1X6PM/ref=dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1
[22:22] <Laurenceb> ^ lol
[22:22] <hallam> Laurenceb: discovered the wonderful world of audiophiles, I see
[22:22] <Laurenceb> yes
[22:23] <natrium_> but is it oxygen free?
[22:23] <natrium_> ahaha, from one of the reviews
[22:23] <natrium_> "A caution to people buying these: if you do not follow the "directional markings" on the cables, your music will play backwards. Please check that before mentioning it in your reviews. "
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[22:26] <hallam> natrium_: 3 hours each way in an Arrow. I'll have to see if SWMBO is up for it
[22:27] <natrium_> hehe
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[22:30] <Laurenceb> hmm right then... hopefully I'll be able to launch in a couple of weeks max
[22:32] <hallam> Laurenceb: has google calculator stopped working for you?
[22:32] <hallam> I can't get it to work without proxying through a machine in the US
[22:32] <Laurenceb> works for me
[22:33] <hallam> weird
[22:38] SteamAtom (n=SteamAto@74-132-3-136.dhcp.insightbb.com) joined #highaltitude.
[22:38] <SteamAtom> well, quite the crowd
[22:38] <SteamAtom> this is Dan, K2VOL
[22:39] <hallam> Hi there
[22:39] <SteamAtom> which side of the pond are you on Hallam?
[22:40] <gordonjcp> hello
[22:40] <SteamAtom> hi Gordon
[22:40] <gordonjcp> SteamAtom: are you also in #hamradio?
[22:40] <SteamAtom> no
[22:40] <hallam> UK
[22:40] <hallam> with CU Spaceflight
[22:41] <SteamAtom> Nice, I'm with Spirit of Knoxville
[22:41] Action: shellevil is in Fife, Scotland, but yet to launch more than a party balloon.
[22:41] <SteamAtom> hey someday we'll have electronics light enough to fly on that too!
[22:41] <SteamAtom> I'm in Kentucky USA
[22:41] <hallam> that's the spirit
[22:41] <hallam> nice work with SNOX, are you guys planning any more flights?
[22:42] Action: gordonjcp is in Glasgow, Scotland
[22:42] <shellevil> SteamAtom: I did a ballpark BOM for a stabilised satellite with imager and transponder in 25g.
[22:42] <Laurenceb> can I ask what you used for ballast on SNOX?
[22:43] <hallam> shellevil, was that actively stabilised?
[22:43] <shellevil> SteamAtom: It's amazing what you can get with todays electronics
[22:43] <shellevil> hall: yes - magnetorquers
[22:43] <SteamAtom> Thanks hallam. I don't think we'll be flying any more SNOX in the near future. We proved it's possible to ride the jet stream across, but the logistics to support it were monumental, and we all have full time jobs
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[22:44] <SteamAtom> sure, I'd like everyone to benefit from our experience in SNOX
[22:44] <SteamAtom> we used denatured alcohol
[22:44] <shellevil> hall: or maybe just one channel - I diddn't really flesh it out fully.
[22:44] <Laurenceb> coils will give you two aixs
[22:44] <SteamAtom> nice shell
[22:44] <hallam> neat
[22:45] <hallam> lose 6 grams and you'll have an N-prize payload
[22:45] <Laurenceb> it its very stable you can use the change in B vector with time
[22:45] <shellevil> hallam: cellphone camera, a couple of solar cells as wings, microSD, stm32, magnetometer, magnetorquer, structure, battery, transponder
[22:45] <SteamAtom> found a little pneumatic valve that was super light - http://www.pneuaire.com/lowwasu34wav.html
[22:45] <shellevil> hall: and maybe a MEMs gyro - wasn't sure
[22:46] <jcoxon> hey everyone
[22:46] <Laurenceb> magnetorquers should give you three axis control of sorts....
[22:46] <Laurenceb> not sure if thats actually poss in practice
[22:46] <Laurenceb> hi
[22:46] <SteamAtom> ni
[22:46] <SteamAtom> hi
[22:47] <shellevil> hallam: only 9600 or so data back for 200km of a pass though at 433, so at best a little pic per pass.
[22:47] <jcoxon> hey SteamAtom welcome to #highaltitude
[22:47] <shellevil> I diddn't consider legalities.
[22:47] <SteamAtom> thanks jcoxon
[22:48] <hallam> did you have any kind of uplink to SNOX?
[22:48] <SteamAtom> lol shell we had some super complicated routines in our SNOX flight computer pic to shut the TX off over the UK
[22:48] <SteamAtom> we didn't on the actual trans-atlantic flights, but we had one tested that worked over HF
[22:49] <SteamAtom> just didn't have time to incorporate it into the flight computer before the trans-atlantic season began
[22:49] <Laurenceb> shellevil: use cc1100 for the downlink
[22:49] <shellevil> Laurenceb: I did a test earlier - I was lazy - no maths - hence the added magnetorquers to the design. 10cm*10cm coil 1 amp-turn, indicated you can get several dozen revs/min/day on a 1Kg cubesat.
[22:49] <jcoxon> SteamAtom, quite a few of us are taking up your mantle
[22:49] <shellevil> lau: physical test
[22:49] <SteamAtom> that's fantastic jcoxon! I hoped it would spur amateur science onward
[22:49] <shellevil> Laurenceb: with a hundred milliwatts
[22:50] <shellevil> jcoxon: yeah - n prize is interesting in some ways.
[22:50] <jcoxon> http://spacenear.us/wiki/doku.php
[22:50] <shellevil> SteamAtom: seen the recent 'accidental' balloon landing on newfoundland from the US?
[22:50] <SteamAtom> ohh jcoxon, I've been talking with Alexei
[22:50] <SteamAtom> no shell hmm
[22:51] <jcoxon> yeah, you are on the SPOT mailing list
[22:51] <shellevil> https://explore.twitter.com/PBH3
[22:51] <shellevil> it doesn't seem to have a webpage
[22:51] <shellevil> recovered by a local ham
[22:51] <shellevil> flew over an airport runway dead on track.
[22:52] <hallam> eit
[22:52] <SteamAtom> haha
[22:52] <SteamAtom> I'm reading the twitter now, glad they were in communication with ATC
[22:52] <SteamAtom> that's important
[22:52] <jcoxon> SteamAtom, what were you plans about NOTAMs on the snox flights?
[22:52] <jcoxon> when it reached the other side for example
[22:53] <SteamAtom> we were just going to remain in contact with ATC via telephone
[22:53] <SteamAtom> we had talked Gander, Prestwick and Santa Maria to warn them we'd be coming
[22:53] <jcoxon> okay, good to know
[22:54] <jcoxon> i guess once flying you could update them accordingly
[22:54] <SteamAtom> yes, we also had a webpage for ATC
[22:54] <SteamAtom> with live position updates relative to nav beacons and airports
[22:55] <SteamAtom> wow who are these guys in owego
[22:55] <jcoxon> the pbh3 launch?
[22:56] <shellevil> Well - google gets you the hams registration info for the callsign.
[22:56] <shellevil> Then it gets you the wifes phone number.
[22:56] <jcoxon> shellevil, you stalker
[22:56] <SteamAtom> haha
[22:56] <jcoxon> those guys are the ones with the alt record
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[22:57] shellevil (n=user@tor/regular/SpeedEvil) joined #highaltitude.
[22:57] <jcoxon> its Project Blue Horizon who work with lockheed
[22:58] <SteamAtom> huh
[22:58] <hallam> http://maps.google.com/maps?hl=en&client=firefox-a&q=48.97366N,+54.15803W&ie=UTF8&ll=48.57479,-58.227539&spn=21.607001,57.128906&t=h&z=5&iwloc=addr they really did get the last possible landing site for a while
[22:58] <SteamAtom> haha yes
[22:59] <shellevil> iceland maybe
[22:59] <jcoxon> i reckon they should of kept flying
[22:59] <shellevil> they must have hit within 100m of water.
[22:59] <shellevil> from google
[22:59] <hallam> I make it more like 30km, but still
[23:00] <shellevil> wateer - not sea
[23:00] <shellevil> they landed on a lake shore
[23:00] <shellevil> unless it's frozen at this time of year
[23:00] <hallam> oh - yes, that was lucky
[23:00] <shellevil> Which isn't quite impossible on reflection.
[23:00] <hallam> I'd guess frozen
[23:00] <SteamAtom> well, jcoxon, ATC asked them to come down, I think it's good to be courteous, we don't want to lose our little loophole in the air regulations
[23:00] <shellevil> Some bits of canada can be chilly.
[23:01] <rjharrison_> SteamAtom: Greetings
[23:01] <jcoxon> SteamAtom, i know, but once you are over its actually more predictable to keep it in the air
[23:01] <rjharrison_> I'm going to have to say nights
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[23:01] <jcoxon> and yes i agree - got to keep on hte right site
[23:02] <SteamAtom> night rj
[23:02] <SteamAtom> :-)
[23:02] <jcoxon> side*
[23:02] <shellevil> jcoxon: yeah - it was going in a really straight line till the cutdown. When it went sideways.
[23:02] <jcoxon> we have our fair share of legalities and loop holes over here
[23:02] <jcoxon> they don't make it easy
[23:02] <SteamAtom> jcoxon your tracking will be much less laborious than our HF brigade, I envy you!
[23:03] <shellevil> 433MHz works out to a few hundred km even on 10MW
[23:03] <shellevil> mW
[23:03] <shellevil> :)
[23:03] <SteamAtom> oh yeah, I'm not familiar with the canadian regs, I just assumed they would be pretty close to the US
[23:03] <jcoxon> SteamAtom, oh we are going HF as well
[23:03] <SteamAtom> what's the max payload jcoxon?
[23:03] <jcoxon> spot ain't that great
[23:03] <jcoxon> in Canada?
[23:03] <SteamAtom> yeah
[23:03] <jcoxon> not sure, ain't my department - i'm on the UK side
[23:04] <shellevil> they allegedly diddn't intend to go over canada
[23:04] <SteamAtom> well you're welcome to use the DTRC network or bits of it if you want
[23:04] <shellevil> but to land in the US
[23:04] <SteamAtom> ah gotcha
[23:04] <jcoxon> sYx66 is on that job
[23:04] <shellevil> their cutdown failed - or comms to it did
[23:04] <SteamAtom> UK seems really tight on the flying radio txing
[23:04] <jcoxon> SteamAtom, we've been working on our own to tell you teh truth , mainly for use in the UK for flights but its easily scalable
[23:04] <jcoxon> 10mW is our max power
[23:04] <SteamAtom> good, ours was pretty kludged together
[23:05] <hallam> SteamAtom: UK did recently loosen up though, 500mW on 868MHz, but nobody's tried it yet
[23:05] <shellevil> 10mW - if you don't need much data - is quite adequate.
[23:05] <hallam> 10mW on 434 actually works pretty well
[23:05] <shellevil> as long as nothing interferes.
[23:05] <jcoxon> i got pictures over it :-)
[23:05] <SteamAtom> lol like one of a hundred thousand car remotes
[23:05] <shellevil> sstv
[23:05] <SteamAtom> nice
[23:06] <SteamAtom> we were really trying hard to figure out how to do SSTV with cheap hardware
[23:06] <jcoxon> i use a gumstix with an audio out and a radiometrix ntx2
[23:06] <jcoxon> running som code from G8KHW
[23:06] <jcoxon> really can't type today
[23:07] <SteamAtom> oh nice what cam with the gumstix
[23:07] <G8KHW> cheap SSTV = camera -> sdcard -> spi -> pic - SSTV methinks
[23:07] <jcoxon> SteamAtom, used a canon A60 and remotely grabbed the pictures over usb
[23:07] <SteamAtom> sdcard to spi? how when it's in the cam?
[23:08] <hallam> solder to the socket in the camera
[23:08] <hallam> but this is easier: http://www.electronics123.com/s.nl/it.A/id.2421/.f
[23:08] <SteamAtom> nice
[23:08] <shellevil> Or maybe easier - simply sample a composite camera at 50.01Hz
[23:08] <SteamAtom> it would be so much simpler if there were cams that were serial
[23:09] <shellevil> SteamAtom: I'm going as fast as i can!
[23:09] <jcoxon> okay i've got to go, SteamAtom if its okay i might email you with some questions about snox and such
[23:09] <hallam> personally I'd use a blackfin, in fact I plan to on the next star tracker flight
[23:09] <SteamAtom> haha
[23:09] Action: shellevil is trying to get one ready for sale from ebay
[23:09] <shellevil> on ebay
[23:10] <SteamAtom> jcoxon, sure, my email on the list or the dan@spiritofknoxville.com is fine
[23:10] <jcoxon> also we have http://groups.google.com/group/atlantic_halo for those who are interested in getting updates and such
[23:10] <hallam> shellevil: how does it compare to cmucam?
[23:10] <SteamAtom> oh my, that blackfin is sexy
[23:10] <shellevil> cmucam?
[23:10] <Laurenceb> I meant to buy one of those
[23:10] <Laurenceb> - the eval module
[23:11] <jcoxon> night all
[23:11] <Laurenceb> you can always get a camera off ebay then grab the images with an adc
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[23:12] <hallam> shellevil: google
[23:12] <Laurenceb> - off component video
[23:12] <shellevil> hallam: dunno - I was planning 1.3MP, local storage of pics or movies to microSD, control over serial, and readout over serial of pics, decimated pics, darkframed pics, or simple 'motion' like functionality.
[23:12] <SteamAtom> ahh laurence. makes sense.
[23:12] <shellevil> hall: selling for maybe 450 quid
[23:12] <shellevil> hallam: 40 quid
[23:13] <shellevil> serial being rs232, or maybe I2C too.
[23:13] <Laurenceb> but its probably more practical to use the little cmos cameras
[23:13] <hallam> sounds good, similar sort of goals as the cmucam, but an alternative is definitely worth having / marketable
[23:13] <SteamAtom> there really is no throw-away SSTV modules out there, which you need for long duration, trial and error results in a lot of balloons in un-recoverable waters
[23:13] <Laurenceb> maybe if you want a cheap high performance cam
[23:14] <Laurenceb> then component video adc is worth doing
[23:14] <shellevil> And flexible enough to go with either 640*480 crap cams, or 250 quid cams with a similar interface, that can take sensible 5MP images with an integration time of 30s.
[23:14] <Laurenceb> but hallam got good results with a cmos camera
[23:15] <shellevil> CMOS isn't only crap anymore
[23:15] <hallam> it's amazing how much difference the optics made to mine
[23:15] <shellevil> used to be CMOS was always worse.
[23:15] <hallam> cmos is typically sold with crap tiny lenses
[23:15] <hallam> and then people are surprised when they get bad results
[23:15] Action: shellevil bought some cams on ebay. Sold as EXview-HAD 1/2 imagers
[23:15] <Laurenceb> we had a serially controlled camera with component video out in some undergrad labs
[23:15] <shellevil> Are 1/3" :(
[23:15] <hallam> I put a $30 bit of glass in front and got some pretty nice pictures
[23:16] <Laurenceb> you can get similar stuff for none crazy prices
[23:16] <hallam> SteamAtom: I figure at least $500/launch for envelope and gas alone, so you don't want too much electronics eating into that
[23:16] <SteamAtom> yes, hallam, that's what SNOX cost
[23:16] <SteamAtom> well, no, $500 total, including electronics
[23:16] <SteamAtom> hmm neat
[23:17] <shellevil> hall: what size imager is that?
[23:17] <shellevil> hallam: and what's the lens?
[23:18] <hallam> "1/4 inch" (4.2 x 3.3mm), lens is the last one on this list: http://www.mars-cam.com/lenses/ccd_cmos/44.html
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[23:20] <shellevil> Saw some 50mm CS mount lenses on ebay, with about 30mm of glass.
[23:20] Action: shellevil stabs the laws of brightness conservation.
[23:20] <SteamAtom> haha
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[23:27] <shellevil> hallam: how do I get to F number from the listed parameters - /me is slow today.
[23:27] <shellevil> Oh - is 'relative apature' F number/
[23:27] <SteamAtom> one thing I'd recommend to everyone flying long duration is test your electronics with dry ice first
[23:27] <hallam> yes
[23:27] <hallam> f/1.2
[23:28] <hallam> SteamAtom: good point. short-duration flights rarely get down to the external temperature
[23:28] <shellevil> Gotta love people making up random names for well known concepts.
[23:28] <hallam> what sort of temps were you guys seeing?
[23:29] <SteamAtom> externally of course it was around -50C, internally, with good insulation it got down to -20C overnight. I don't have the data in front of me, but I'll publish it on the snox site soon
[23:29] <SteamAtom> were you on the DTRC listening?
[23:30] <SteamAtom> the HF TX suffered severely from drift even at those temperatures
[23:30] <hallam> I was for some of the flights
[23:30] <SteamAtom> lol so you may remember it didn't drift smoothly, it whipped around like a madman at the dial
[23:30] <hallam> it's good to hear that it didn't go much below -20
[23:31] <hallam> that's when some ceramic capacitors start going crazy
[23:31] <hallam> I guess there's no power budget for active heaters\
[23:31] <SteamAtom> yes we had enough AA batteries to keep the temp above that, we had a temp setpoint at -20C for the resistive heater to turn on, but it didn't need to for most flights
[23:31] <hallam> heh
[23:31] <hallam> did you use lithium AAs?
[23:31] <SteamAtom> live and learn we could have ditched insulation or AAs
[23:31] <Laurenceb> whats the difference between back focal lenght and focal lenght?
[23:32] <hallam> back focal length = focal length - physical length of the lens
[23:32] <hallam> i.e. it's the distance from the back of the lens to the image palne
[23:32] <hallam> plane
[23:32] <Laurenceb> oh course
[23:32] <Laurenceb> got it
[23:32] <hallam> I did some calcs which indicated lithium AAs are best for flights less than a couple of weeks long, after which you use solar panels
[23:32] <SteamAtom> you are ambitious!
[23:33] <SteamAtom> we thought it lucky to plan enough battery power for a 4 day flight, which we had
[23:33] <SteamAtom> and that was 42AAs at our consumption and TX rate
[23:34] <hallam> well I was just trying to get a first idea of whether it was better to go with batteries or solar
[23:34] <SteamAtom> yeah
[23:34] <hallam> and batteries clearly won
[23:34] <SteamAtom> the problem is that the jet stream takes it pretty far north
[23:34] <SteamAtom> and panels aren't likely to be articulated
[23:34] <hallam> right
[23:34] <natrium_> hi SteamAtom
[23:34] <hallam> so you really need a lot of panel area
[23:35] <SteamAtom> hi Natrium
[23:35] <SteamAtom> thanks for the invite
[23:35] <natrium_> thanks for joining :)
[23:35] <SteamAtom> nice flight, though spot was a little spotty
[23:35] <natrium_> we sure could tap your experience :)
[23:35] <natrium_> yeah
[23:35] <SteamAtom> be glad to help, I want that ocean to be conquered by amateurs
[23:36] <natrium_> i am a little worried that the RF section isn't getting enough power, as i didn't reverse engineer the power system very well
[23:36] <shellevil> Should have flown one unmodded :)
[23:36] <natrium_> going to run some more ground tests
[23:36] <SteamAtom> haha possibly, or just do more vigorous ground testing
[23:36] <hallam> might be a temperature thing?
[23:36] <SteamAtom> do you do cryo testing?
[23:36] <natrium_> shellevil, bill brown sent me the data of an unmodded flight
[23:36] <SteamAtom> yes, very possibly
[23:37] <shellevil> natrium_: work ok? or similarly spotty
[23:37] <natrium_> it looks better, a message every 10 mins
[23:38] <natrium_> but it stops above 60k ft
[23:38] <natrium_> but that's probably because of the gps
[23:38] <natrium_> in other news, i got an email about my iridium minutes expiring
[23:38] <shellevil> what's your orientation?
[23:38] <natrium_> i can extend them for 30 days for $75
[23:38] <shellevil> :/#
[23:39] <natrium_> we better launch 2nd flight within that timeframe
[23:39] <natrium_> :P
[23:39] <SteamAtom> regarding launching, the calcs I did show most efficient use of helium is by launching right after sunset
[23:40] <natrium_> SteamAtom, any reason why you went with a pressurized ballast tank as opposed to having a hole at the top?
[23:40] <SteamAtom> oh we ditched the pressurized tank after one flight, that was a royal mess
[23:40] <SteamAtom> SNOX 1 had that
[23:41] <natrium_> did you use a check valve at the top? or just a hole?
[23:41] <SteamAtom> SNOX 2-5 had gravity feeds. we thought the alcohol wouldn't flow fast enough through the submilimeter valve
[23:41] <Laurenceb> http://ballons.cnes.fr:8180/html/mir/resmi_gb.htm
[23:41] <natrium_> there's some concern that alcohol might be evaporating too fast
[23:41] <SteamAtom> just a 1mm hole covered with fabric to prevent debris entry
[23:41] <SteamAtom> it's very calm in flight
[23:42] <natrium_> ah cool
[23:42] <SteamAtom> with a small enough hole, the evap rate will be very low
[23:42] <Laurenceb> SteamAtom: surely you want to launch an hour or so before sunset
[23:42] <Laurenceb> so you reach apogee just after sunset
[23:42] <natrium_> SteamAtom, that's the valve we intend on using --> http://spacenear.us/wiki/doku.php?id=ballast:valve
[23:44] <SteamAtom> laurenceb, you don't want your helium to get heated by the sun, unless you're sure it will cool entirely by the time it reaches altitude
[23:44] <Laurenceb> guess so
[23:44] <SteamAtom> nice natrium, looks tiny.
[23:44] <Laurenceb> you dont want to risk it
[23:44] <SteamAtom> no, it's pretty precious
[23:44] <SteamAtom> once you let go ;-P
[23:44] <Laurenceb> so at the expense of ~1 hours flight time
[23:45] <natrium_> SteamAtom, a little worried about flow rate
[23:45] <SteamAtom> too high or low
[23:45] <SteamAtom> laurenceb
[23:45] <natrium_> might be a bit low
[23:45] <Laurenceb> but our envelope should reach equilibrium quite fast with the surrounding air
[23:45] <SteamAtom> laurenceb we were lucky to get within 5 hours of the desired launch time!
[23:46] <Laurenceb> yeah :P
[23:46] <Laurenceb> its usually the same here
[23:46] <SteamAtom> due to rapid construction requirements, we had to build the snoxes back to back
[23:46] <Laurenceb> does anyone have the rogallo launch video?
[23:47] <SteamAtom> the problem is, if your helium is hotter than surrounding air, it will then contract and lose lift as it cools
[23:47] <SteamAtom> and lower your altitude float, and potentially suck in some air
[23:48] <Laurenceb> sure
[23:49] <SteamAtom> natrium, I did a lot of lab tests on the flow rates from each flight ballast system, I let it fill a graduated cylinder over and over timing each fill
[23:49] <Laurenceb> you want to avoid that, but as your ascending its inevitable to some extent :-/
[23:49] <SteamAtom> true
[23:49] <Laurenceb> unless you go for stratospheric apogee
[23:49] <Laurenceb> where t starts to increase again
[23:50] <hallam> doesn't the helium start off significantly colder than ambient due to expansion from the cylinder?
[23:50] <SteamAtom> One thing that we really wanted to quantify but never had time to, was the actual superheating temperuture amount
[23:50] <SpeedEvil> I thought about doing that with an IR thermometer up to the top of the envelope
[23:51] <SpeedEvil> but polythene is IR transparent
[23:51] <Tigga_> we looked at heated helium once
[23:51] <akawaka> SteamAtom: SNOX was awesome, congrats
[23:51] <SteamAtom> yeah, hallam, but it will quickly warm to ambient when in a big thin plastic envelope, on the time scales of 15-min to 30 min
[23:51] <Tigga_> IIRC there wasn't much change with change in temp
[23:51] <SteamAtom> thanks, akawaka
[23:51] <Tigga_> at all
[23:51] <Laurenceb> you couls stick a thermocouple a few m into the envelope
[23:51] <SteamAtom> really Tigga_! how did you instrument it
[23:52] <Tigga_> we did some sums
[23:52] <Laurenceb> :P
[23:52] <Laurenceb> thermopile needs a target
[23:52] <SteamAtom> Laurenceb, someone needs to put a lot of them in the envelope actually
[23:52] <SteamAtom> sums?
[23:53] <hallam> SteamAtom: it was only a fairly quick calculation, nothing experimental i'm afraid
[23:53] <SteamAtom> oh ok
[23:53] <hallam> maybe we ought to do that with badger sometime, it has that otherwise-useless string of temperature sensors on thin wires from the teddy launch
[23:53] <SteamAtom> it definetly has a serious effect, recall SNOX IV's resurrection from doom at the second dawn
[23:53] <Laurenceb> any idea why it lost altitude so badly?
[23:54] <hallam> we could shove that inside the envelope without too much trouble, and they're not sharp enough to endanger the envelope
[23:54] <Laurenceb> condensation?
[23:54] <SpeedEvil> SteamAtom: maybe you had the same issue as NASA
[23:54] <SteamAtom> we have no concrete conclusion, but most likely it was a combination of a balloon that was dragged through a parking lot before we owned it (did not find that out until after flight)
[23:55] <SpeedEvil> http://www.independent.co.uk/news/science/lost-in-space-bat-hitches-ride-on-shuttle-1646093.html
[23:55] <akawaka> parking lots have en effect on helium?
[23:55] <SteamAtom> and as it sunk, I think you are right laurenceb, it may have descended into air that caused condensation and frost
[23:55] <SteamAtom> haha akawaka, not much, but they sure do affect polyethylene
[23:56] <Laurenceb> yeah, we need to avoid that
[23:58] <SteamAtom> the temperature-induced helium expansion is what zero pressure balloons struggle against most
[23:59] <SteamAtom> it expands the helium you were full of all night, and spurts it out, and then come sunset, you're suddenly wishing you still had that extra helium still, and have to drop ballast.
[23:59] <SteamAtom> one idea we had planned was to make a cover for the balloon from aluminized mylar emergency blankets
[00:00] --- Tue Mar 24 2009