highaltitude.log.20090426

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[00:02] <gordonjcp> hah
[00:02] <gordonjcp> I take issue with "Polaris is just about the brightest star in the sky"
[00:02] <gordonjcp> uh, no
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[00:47] Action: shellevil ponders curie based cut-downs.
[00:48] <shellevil> http://www.dealextreme.com/details.dx/sku.13516 - sort of thing has a curie point of about 80C
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[07:15] <Dan-K2VOL> anyone up yet?
[07:16] <natrium42> i am still up :)
[07:16] <natrium42> sup dan?
[07:16] <Dan-K2VOL> haha nite owl too eh alexei
[07:16] <Dan-K2VOL> I just threw together a site to publish the SNOX docs
[07:17] <natrium42> :)
[07:17] <natrium42> cool, url?
[07:18] <Dan-K2VOL> Just a little bit of info on there so far, I'm trying to get it all cleaned up and tagged with decent copyleft notices
[07:18] <Dan-K2VOL> http://web.me.com/dbowen1/Spirit_of_Knoxville_Published_Information/SNOX_DOCS_Blog/SNOX_DOCS_Blog.html
[07:23] <natrium42> neat
[07:24] <natrium42> "Due to regulatory issues, the HF transmitter does not operate over the United States" <--- the PBH guys seemed to use HF over USA
[07:24] <natrium42> did the regulations change?
[07:24] <Dan-K2VOL> well, no
[07:24] <Dan-K2VOL> you can't use 10MHz for telemetry at all
[07:25] <Dan-K2VOL> they were just breaking the regs, as far as I can recall, which is why ours turned on out at sea
[07:25] <Dan-K2VOL> but I'm not going to report them, lord knows we broke a few before we understood them all
[07:26] <Dan-K2VOL> you also have to have a 440MHZ+ control link for automated HF telemetry I think as well, which is rediculous
[07:27] <natrium42> ah, i see
[07:30] <Dan-K2VOL> how's the spothacking going, you guys going to continue exploring that?
[07:31] <natrium42> well, it worked as well as spot can work it seems
[07:31] <natrium42> so it's good enough for first transatlantic attempt
[07:32] <Dan-K2VOL> cool, very cost effective
[07:32] <natrium42> (second attempt will have iridium)
[07:32] <Dan-K2VOL> nice
[07:32] <natrium42> i set up a laptop with modem at syx66
[07:32] <icez_> transatlantic :o
[07:33] <natrium42> dialing in via rs232 modem is working
[07:33] <natrium42> going to connect it to avr and write a packet system
[07:33] <Dan-K2VOL> what is syx66
[07:33] <Dan-K2VOL> nice
[07:33] <natrium42> he is a member of the team who lives about 15 min away from me
[07:33] <natrium42> :)
[07:34] <Dan-K2VOL> gotcha
[07:34] <natrium42> apparently he doesn't use his phone line
[07:34] <Dan-K2VOL> haha, you keep it tied up eh
[07:34] <natrium42> so it's excellent to set up a dialin server that iridium will dial
[07:34] <natrium42> :D
[07:34] <Dan-K2VOL> good plan!
[07:34] <natrium42> had to buy a serial modem for testing
[07:35] <natrium42> those things are hard to find nowadays
[07:35] <Dan-K2VOL> hmm, those are probably expensive too now
[07:35] <natrium42> i lucked out with mine, got it for $10 brand new
[07:35] <Dan-K2VOL> nice find
[07:35] <Dan-K2VOL> have to wade through all the winmodem crap
[07:35] <natrium42> so once the system is working with it, i can swap it out for iridium phone
[07:36] <natrium42> no need to waste satellite minutes while testing :D
[07:36] <Dan-K2VOL> very good plan
[07:37] <natrium42> do you have any experience waterproofing the payload btw?
[07:37] <Dan-K2VOL> not really. it's difficult to do and keep light
[07:38] <Dan-K2VOL> I've tried with a ROV submersible project, and determined that the only reliable way is rubber compression seals on a solid box (plastic)
[07:39] <Dan-K2VOL> to pass wires through it
[07:39] <Dan-K2VOL> but I was using a Pelican case, which is polypropylene, and hard to bond to
[07:40] <Dan-K2VOL> or you could just pot it all with some lightweight substance
[07:40] <Dan-K2VOL> a lot of hot glue :-P
[07:41] <Dan-K2VOL> what's your email alexei
[07:41] <natrium42> natrium@gmail.com
[07:42] <natrium42> maybe if i found a sufficiently big solid piece of styrofoam
[07:42] <natrium42> i could hollow it out or something
[07:42] <natrium42> with hot wire
[07:42] <Dan-K2VOL> sent you one of our hysplit auto-forecasts
[07:43] <Dan-K2VOL> I see you're doing them too, but wanted to show you the multiple altitudes
[07:43] <natrium42> pretty close, hmm
[07:43] <natrium42> so no need to worry about the way hysplit handles altitude then
[07:43] <natrium42> very good
[07:44] <Dan-K2VOL> what do you mean
[07:44] <natrium42> well, hysplit doesn't really let you set a fixed altitude
[07:44] <Dan-K2VOL> oh right
[07:44] <natrium42> so i was worried that it would give a different result than to an actually controlled flight
[07:44] <Dan-K2VOL> yeah this allows you to get an idea of what you'll experience if you drift high or low
[07:45] <natrium42> btw, did you use hysplit for the trajectory forecast on the google map?
[07:45] <Dan-K2VOL> yep, boy I forgot a bout that
[07:45] <Dan-K2VOL> it was a local linux install of HYSPLIT
[07:45] <natrium42> ok, so not some custom system based on raw GFS data?
[07:46] <natrium42> aaah, they publish their source code??
[07:47] <Dan-K2VOL> oh yes, it's a nice TCL program that runs great on linux or osx
[07:47] <Dan-K2VOL> or you can just run it command line
[07:50] <natrium42> http://www.arl.noaa.gov/HYSPLIT.php
[07:50] <natrium42> can't seem to find linux version
[07:55] <Dan-K2VOL> well, the Apple based one is the one
[07:55] <Dan-K2VOL> I think we did run it on OSX but really it's pretty standard I believe
[07:56] <natrium42> gotcha
[07:56] <natrium42> should be able to run the windows version through wine
[07:57] <Dan-K2VOL> emailed you a printout from the forecast site we set up, it allowed a nice visualization comparison from the CRWS SFSU jet stream server
[07:58] <Dan-K2VOL> well, I've gotta hit the hay, I'll ttyl Alexei
[07:58] <natrium42> cool, thanks
[07:58] <natrium42> g'nite
[08:00] <Dan-K2VOL> nite
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[08:23] <edmoore> morninall
[08:25] <natrium42> yo edmoore
[08:25] <edmoore> what's happening in canada? other than it being dark
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[08:38] <natrium42> trying to install activetcl on wine :S
[08:44] <edmoore> yummy
[08:45] <edmoore> speaking of which, breakfast time
[08:46] <natrium42> haha, bon appetite
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[08:55] <rjharrison> Hi all
[08:56] <rjharrison> any news of a launch today
[08:58] <gordonjcp> my sister is launching her new house
[08:58] <gordonjcp> as it were
[08:58] <gordonjcp> heading up there in an hour to help with the move
[08:59] <rjharrison> lol
[08:59] <rjharrison> cool
[08:59] <rjharrison> Good luck and watch your fingers moving furnature
[08:59] <gordonjcp> heh
[08:59] <rjharrison> furniture even
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[10:28] <Laurenceb> hi
[10:36] <gordonjcp> Laurenceb: morning
[10:40] <edmoore> hi Laurenceb
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[11:28] <Laurenceb> hi sbasuita
[11:28] <sbasuita> Laurenceb, morning
[11:28] Action: Laurenceb has been eating his gruel
[11:30] <sbasuita> DanielRichman, do you get a delay with compiz when you maximise/minimise windows on jaunty? (with fglrx)
[11:34] <edmoore> you get a delay in admission to the real world for chewing up so much cpu
[11:36] <DanielRichman> sbasuita, slight delay on maximise.
[11:56] <Laurenceb> firefox just broke :-/
[11:56] <DanielRichman> Impossible! How did it break?
[11:56] <Laurenceb> " you have chosen to download index.php which is a php file"
[11:56] <Laurenceb> it was the latest update
[11:56] <gordonjcp> Laurenceb: that's a broken server
[11:57] <DanielRichman> indeed
[11:57] <DanielRichman> what's the URL?
[11:57] <Laurenceb> ah yeah corse
[11:57] <Laurenceb> avr freaks
[11:57] <gordonjcp> Laurenceb: firefox doesn't give a toss what the file extension is, it goes by what the server tells it to do
[11:57] <Laurenceb> yeah
[11:57] <edmoore> works for me Laurenceb
[11:57] <DanielRichman> yeah. me too
[12:01] <Laurenceb> its the forum search
[12:03] <sbasuita> Laurenceb, send mail to webmaster@avrfreaks.whatever
[12:03] <DanielRichman> the forum search? hmm
[12:04] <DanielRichman> Laurenceb, which bit of the forum search?
[12:04] <Laurenceb> search for say fixed point in the avr gcc forum
[12:05] <DanielRichman> That's strange
[12:05] <DanielRichman> if I search for 'moo' its fine, but searching for fixed point results in bad things
[12:06] <DanielRichman> the file it gives you is empty. Maybe a code bug
[12:06] <Laurenceb> yeah
[12:08] <Laurenceb> http://www.avrfreaks.net/index.php?name=PNphpBB2&file=printview&t=73345&start=20
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[12:46] <DanielRichman> jcoxon, You know you linked me the new dlistener protocol... the bearing and speed fields, can they just be left blank? Shall I implement this protocol or keep the old one - if the tracker will still understand the old one then that is easier.
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[12:50] <jcoxon> DanielRichman, i'd implement the old one
[12:50] <jcoxon> yeah leave them blank - hope thats okay
[12:51] <DanielRichman> jcoxon, ok. I'll just use the old one. but with a checksum.
[12:51] <DanielRichman> Also, in the old one, it was hinted that custom data could include commas, but the new protocol suggests otherwise.
[12:51] <jcoxon> DanielRichman, we really need to draft a new idea
[12:52] <jcoxon> i recommend seperate with commas, have count,time,lat,lon,alt
[12:52] <jcoxon> we'll draft a proper protocol soon
[12:52] <DanielRichman> jcoxon, currently our code outputs this:
[12:52] <DanielRichman> * <E-LONGITUDE DDD.DDDDDD>,<ALTITUDE METERS MMMMM>,<GPS_FIX_AGE_HEXDUMP>,
[12:52] <DanielRichman> * <SYSTEM_STATE_DATA_HEXDUMP>,<PAYLOAD_MSG_ST_HXDMP_4LSB>
[12:52] <DanielRichman> * <NEWLINE> */
[12:52] <DanielRichman> whoops
[12:52] <DanielRichman> a line got cut off there
[12:52] <jcoxon> that sounds about right
[12:52] <DanielRichman> * <E-LONGITUDE DDD.DDDDDD>,<ALTITUDE METERS MMMMM>,<GPS_FIX_AGE_HEXDUMP>,
[12:52] <DanielRichman> * <SYSTEM_STATE_DATA_HEXDUMP>,<PAYLOAD_MSG_ST_HXDMP_4LSB>
[12:52] <DanielRichman> * <NEWLINE> */
[12:52] <jcoxon> we'll adapt for now
[12:53] <DanielRichman> Oh right, slash at beginning of comment ;)
[12:53] <DanielRichman> /* $$A1,<INCREMENTAL COUNTER ID>,<TIME HH:MM:SS>,<N-LATITUDE DD.DDDDDD>,
[12:53] <DanielRichman> * <E-LONGITUDE DDD.DDDDDD>,<ALTITUDE METERS MMMMM>,<GPS_FIX_AGE_HEXDUMP>,
[12:53] <DanielRichman> * <SYSTEM_STATE_DATA_HEXDUMP>,<PAYLOAD_MSG_ST_HXDMP_4LSB>
[12:53] <DanielRichman> * <NEWLINE> */
[12:53] <DanielRichman> there
[12:53] <jcoxon> thats fine
[12:53] <jcoxon> before you fly - submit a full string to rjharrison and he'll update the server
[12:54] <DanielRichman> ok.
[12:54] <DanielRichman> How common are errors in RTTY? Because we did seem to get a few when we were trying it out yesterday
[12:54] <DanielRichman> although that was with a trashy antenna on the arduino
[12:55] <jcoxon> hmmm i've found that either it copies fine or it goes all wrong
[12:55] <DanielRichman> hmm. ok
[12:56] <DanielRichman> I think the fault was with the little circuit generating the two voltages for the transmitter.
[12:56] <jcoxon> how are you going about that?
[12:56] <DanielRichman> 5v --- potentiometer --- potentiometer --^-- fixed resistor -- 0v
[12:57] <DanielRichman> with a transistor shorting over the first potentiometer to change the voltage
[12:57] <DanielRichman> and the ^ going to the radio
[12:57] <jcoxon> oh okay
[12:57] <DanielRichman> there's probably a better way to do it
[12:57] <jcoxon> i've found that 2 pins with resistors on them works very well
[12:58] <DanielRichman> resistors on the pins or potential dividers?
[12:58] <jcoxon> 8 ------------------------------- EN
[12:58] <jcoxon> 9 ---22K -------------\
[12:58] <jcoxon> ---------- TX
[12:58] <jcoxon> 10---22K -- 2K2 - 2K2-/
[12:58] <jcoxon> GND-------------------------------GN
[12:58] <jcoxon> 3v-------------------------------VCC
[12:58] <jcoxon> did that come through?
[12:58] <DanielRichman> yes
[12:58] <DanielRichman> Oh i see
[12:58] <DanielRichman> so it makes a potential divider between the pins
[12:58] <jcoxon> yeah
[12:58] <DanielRichman> because when 10 is high, 9 is grounded
[12:58] <DanielRichman> very neat.
[12:59] <jcoxon> those resistor values gives me nearly 425Hz shift
[12:59] <jcoxon> so works very well
[12:59] <DanielRichman> could just put preset pots instead
[12:59] <jcoxon> yup
[13:00] <jcoxon> but it works very well, rjharrison has used it to great effect as well
[13:00] <DanielRichman> Cool. Will bear that in mind
[13:00] <DanielRichman> Might even build it now
[13:00] <DanielRichman> ;)
[13:02] <DanielRichman> although I will have to use different resistors I expect as my arduino is running at 5v
[13:03] <jcoxon> yes thats true
[13:03] <jcoxon> i've got a 3.3v one
[13:12] <DanielRichman> jcoxon, is there any advantage using fixed resistors? are potentiometers bad when going up or something?
[13:13] <jcoxon> ummm, can't really think of any reason - resistors are perhaps a tiny bit more solid
[13:14] <gordonjcp> fixed resistors are considerably cheaper
[13:14] <gordonjcp> and no moving parts
[13:14] <gordonjcp> less to go wrong
[13:14] <jcoxon> yeah, simpler the better really
[13:14] <DanielRichman> it's the no moving parts bit I was thinking about
[13:15] <DanielRichman> the advantage of using pots is that I can tune it better to a 425 shift.
[13:15] <jcoxon> the filters are pretty damn good
[13:15] <jcoxon> you don't need a perfect shift
[13:31] <shellevil> http://www.nhpa40.org/b2b/batteries/1/enameled_copper_clad_50.html hmm
[13:31] Action: shellevil is looking for fine Al wire.
[13:33] Action: sbasuita is looking for hench enameled cooper wire (1/8")
[13:33] <sbasuita> shame maplin don't do it :(
[13:34] <shellevil> hench?
[13:34] <sbasuita> shellevil, big-ass
[13:34] <sbasuita> ; )
[13:37] <sbasuita> DanielRichman, check out pidgin-encryption
[13:37] <shellevil> seems enamel wouldn't maybe be an ideal protection at that thickness, unless youw ind it carefully
[13:37] <sbasuita> oh
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[13:37] <sbasuita> shellevil, i'm not going to wind it though. Will use it for elements of a yagi i'm building
[13:38] <shellevil> sbasuita: ah
[13:38] <shellevil> sbasuita: are you fixed on 1/8"?
[13:39] <sbasuita> shellevil, according to some plans, yes
[13:39] <edmoore> yo all
[13:39] <shellevil> 8mm microbore copper tube
[13:39] <sbasuita> shellevil, http://www.fredspinner.com/W0FMS/CheapYagi/vjbcy.html 70cm
[13:46] <shellevil> http://www.screwfix.com/prods/14963/Electrical-Supplies/Cable/Conduit-Wiring/6491X-10-0mm-Conduit-Wiring-Cable-Green-Yellow-50m
[13:46] <shellevil> something like that will work - the copper is the right diameter
[13:46] <shellevil> (10mm^2 = about 4mm)
[13:46] <shellevil> you'd want to find somewhere selling it by the metre though
[13:50] <sbasuita> shellevil, yeah. I'm sure there are plenty of stores selling different varieties - just got to go and have a look.
[13:52] <shellevil> And Al rod will probably work just fine too
[13:53] <sbasuita> shellevil, needs to be bendable (for the driven element) and I'd rather use the same material for all the elements.
[13:54] <shellevil> Almost any metal is quite bendable at 3.5mm dia
[13:54] <shellevil> Copper and aluminium by hand even, though you can even anneal it.
[13:55] <rjharrison> hi all
[13:55] <shellevil> Most copper wire is supplied 'half-hard' - if you anneal it, it goes soft and easily bent
[13:55] <shellevil> hi
[13:55] <rjharrison> hi shellevil
[13:56] <rjharrison> DanielRichman: How are you going with getting rtty to work
[13:56] <DanielRichman> rjharrison, got it working fine :)
[13:57] <DanielRichman> we also alienated a few locals by walking around with a laptop and a box making strange beeps, trying to pick up the signal :)
[13:58] <rjharrison> The two resistors is the easiest way I found to date
[13:58] <rjharrison> Also it seems to behave at altitude
[13:58] <shellevil> rjharrison: most girls expect flowers or chocolate though.
[13:59] <rjharrison> If you use PWM it seems to affect the shift if the temp changes
[13:59] <rjharrison> lol
[13:59] <sbasuita> DanielRichman, can you solder to aluminium?
[13:59] <rjharrison> No not easily
[13:59] <rjharrison> You can with special gasses
[14:00] <sbasuita> DanielRichman, you have special gasses right?
[14:00] <DanielRichman> sbasuita, you could try the welder in the workshop at school
[14:00] <sbasuita> hah
[14:00] <shellevil> You can solder to it with 'normal' solder, and a bit of swearing.
[14:00] <DanielRichman> ;)
[14:00] <rjharrison> lol
[14:00] <shellevil> General procedure is to take some liquid flux, and a kitchen scouring pad
[14:01] <sbasuita> DanielRichman, think the workshop has 1/8 inch enameled copper rods?
[14:01] <DanielRichman> sbasuita, no
[14:01] <sbasuita> : (
[14:01] <shellevil> use the scouring pad - wet a bit with flux - to abrade the surface of the aluminium to remove the oxide layer - while staying under the flux
[14:01] <shellevil> then with a very hot iron, solder to the joint
[14:02] <sbasuita> Sounds like fun
[14:03] <sbasuita> DanielRichman, when you getting the bnc/coax from maplin?
[14:03] <rjharrison> DanielRichman: Seems like you guys are gettin on with your payload. Have you gone for the radiometrix, lassen avr aproach?
[14:04] <sbasuita> rcaron, yes
[14:04] <DanielRichman> rjharrison, yes. I have all three infront of me ;)
[14:04] <DanielRichman> sbasuita, <TAB> usage fail
[14:04] <sbasuita> xchat fail
[14:04] <sbasuita> it's meant to detect who spoke last and priorities
[14:04] <sbasuita> prioritise*
[14:04] <sbasuita> usually works nicely
[14:05] <rjharrison> I'm assuming that sbasuita is with you on this project
[14:05] <sbasuita> rjharrison, yes
[14:05] <rjharrison> Are you guys based near Cambridge?
[14:06] <sbasuita> rjharrison, we're based around reading
[14:06] <rjharrison> DanielRichman: Which avr are you using?
[14:06] <DanielRichman> rjharrison, atmega168 from an arduino board
[14:06] <sbasuita> longest url ever: www.electrical-insulators-and-copper-ground-bars.com
[14:06] <rjharrison> lol
[14:07] <DanielRichman> rjharrison, although we won't be using the arduion library
[14:07] <edmoore> good
[14:07] Action: edmoore vomits
[14:07] <rjharrison> If you got the data cable for the lassen iQ from dpie then be carefull as the header is around the wrong way
[14:07] <edmoore> The lassens gave horrendous altitude data in the last flight
[14:08] <edmoore> looking forward to some ublox action soon
[14:08] <sbasuita> rjharrison, DanielRichman ordered the one recommended in the datasheet (book)
[14:08] <rjharrison> Sounds like a swedish porn movie
[14:08] <DanielRichman> rjharrison, yeah, almost fell foul of that one.
[14:09] <rjharrison> I fried my first lassen iQ with that. I assumed it was correct and put it on the way the cable dent in the case suggests. Bang
[14:09] <rjharrison> sbasuita: I used to live in twyford as a kid
[14:10] <rjharrison> Went to Henley College for A levels a few years ago. Actually decades ago 37 now
[14:11] <rjharrison> Also the data cable is a bit wide. If you make a PCB at some point the header from Sparkfun is the correct size and you don't have to bend the flaps
[14:11] <sbasuita> rcaron, right. Me and daniel are actually southwest of reading (bracknell and yateley). but alex is in reading
[14:12] <rjharrison> hehe tab got you
[14:12] <edmoore> bracknell
[14:12] <edmoore> woooooo
[14:12] <edmoore> i am in guildford on thursday
[14:12] <edmoore> thursday week, even
[14:12] <sbasuita> naow!
[14:12] <rjharrison> The Point that is all I have to say about bracknell
[14:12] <rjharrison> Unless it has been torn down
[14:12] <sbasuita> rjharrison, still there
[14:13] <sbasuita> edmoore seems to know a bit more about bracknell
[14:13] <edmoore> i know that it is near guildford
[14:13] <rjharrison> Ish
[14:13] <edmoore> and that the met office centre is based there
[14:13] <rjharrison> Just off the M3 unless it's moved
[14:13] <DanielRichman> rjharrison, how long did you leave the wrong-way-round datacable plugged in?
[14:13] <edmoore> or at least it was whenever bluepeter went to visit them about 1.5 decaDES AGO
[14:13] <edmoore> whoops
[14:13] <rjharrison> About 1 second
[14:13] <rjharrison> under power
[14:14] <DanielRichman> how were you powering it?
[14:14] <rjharrison> If you still get data out of it then you're fine but mine was F**Ked after that
[14:14] <sbasuita> Yeah, met office is long gone
[14:14] <rjharrison> 3.3
[14:14] <rjharrison> v
[14:15] <sbasuita> rjharrison, yep, it's some pullups that _have_ to be there else it commits suicide
[14:15] <sbasuita> You would think trimble would give more of a warning
[14:15] <edmoore> you're doing that to annoy me
[14:15] icez (n=icez@ip68-109-170-236.ph.ph.cox.net) joined #highaltitude.
[14:15] <rjharrison> dpie are the buggers
[14:15] <DanielRichman> we got the cable from samtec
[14:15] <DanielRichman> it's exactly the same
[14:15] <DanielRichman> wrong way round
[14:16] <rjharrison> Humm perhaps there is a company supplying a duff bunch
[14:16] <sbasuita> How can it be the wrong way round? It doesn't have numbers printed on it?
[14:16] <rjharrison> The connector should have been at the other end of the cable
[14:16] <rjharrison> Well you normally take red as pin 1
[14:16] <rjharrison> now if you do that and connect it the cable runs under the lassen
[14:17] <rjharrison> it should run the other way !
[14:17] <rjharrison> DanielRichman: Knows what I mean
[14:18] <DanielRichman> sbasuita, there's a little notch, a bump on the lassen to allow the cable to run underneath it
[14:18] <DanielRichman> if you plug it in with the cable in the provided space it's the wrong way around
[14:18] <rjharrison> edmoore how long is turnaround from olimex ish?
[14:18] <edmoore> 10 days or something
[14:18] <rjharrison> Cool next week for the PCB
[14:18] <rjharrison> I'm going to submit the next version next week
[14:20] <rjharrison> What have you done to you iQ then edmoore. Would any of that crap on the payload affected the gps signal?
[14:21] <edmoore> it's possible that a lower snr would make the internal filters stick to their model a bit more than the measurement
[14:21] <edmoore> and their model probably assumes zero-mean vertical rates
[14:22] <rjharrison> there was a little baggage on board the last one
[14:22] <edmoore> not much in the way of emi
[14:22] <shellevil> that would be a good thing to test
[14:22] <shellevil> emissions at 1.?GHz in the GPS band
[14:23] <edmoore> .573 or something
[14:23] <edmoore> there is a vid from the downward camera on our vimeo site
[14:23] <edmoore> yeah, it would be nice to test
[14:23] <edmoore> we could probably do it with our gps
[14:23] <edmoore> SNR metrics
[14:23] Action: shellevil checks.
[14:23] <shellevil> At least 433 is nicely out - 3.6*
[14:23] <edmoore> yep
[14:23] <edmoore> very convenient
[14:24] <rjharrison> damn harmonics
[14:25] <sbasuita> Anybody know how to use gnuplot without invoking the kitchen sink?
[14:25] <edmoore> zeusbot is useless
[14:25] <sbasuita> How about plotting a quadratic for a start
[14:26] <edmoore> http://www.vimeo.com/cuspaceflight/videos
[14:26] <edmoore> rjharrison: first video there is the downward facing flip camera
[14:26] <edmoore> that's all there is atm I'm afriad
[14:26] <rjharrison> Cool
[14:27] <rjharrison> goog quality
[14:27] <rjharrison> good
[14:27] <shellevil> sbasuita: plot x^2+3
[14:27] <edmoore> really?
[14:27] <rjharrison> Shame about the straw
[14:27] <sbasuita> gnuplot> plot x^2+3
[14:27] <sbasuita> non-integer passed to boolean operator
[14:27] <shellevil> sbasuita: err - it's something like that
[14:27] <edmoore> not even close :p
[14:28] <edmoore> x = linspace(-5,5,500);
[14:28] <edmoore> y = (x^2)+3;
[14:28] <edmoore> plot(x,y)
[14:28] <shellevil> you can do it teh other way too
[14:29] <shellevil> I can't think ATM
[14:29] Action: shellevil has been lifting around 60Kg 30m^2 tarpaulin in the garden.
[14:29] <edmoore> fair enough
[14:29] <shellevil> And I don't have gnuplot installed ATM.
[14:29] <edmoore> i've been revising. physically not very exhausting
[14:29] <shellevil> My main computer ate itself.
[14:30] <edmoore> hecne had to gym for bout 2 hours last night just to break myself so I could sleep. It's a crappy existance, the exam one
[14:30] <shellevil> fortunately shortly after backups, but...
[14:30] <edmoore> hecne? I have no idea what that is meant to be
[14:30] Action: shellevil has 'exam' in 2 weeks - anothet car theory test.
[14:31] <edmoore> 6 between now and wednesday week
[14:31] <edmoore> then finsihed
[14:32] <shellevil> http://b3ta.com/questions/accidentallyerotic/post48150 - exam related
[14:33] <edmoore> smug posting
[14:35] <shellevil> what're you doing again?
[14:36] <edmoore> doesn't really sit comfortably under an umbrella as a mix of modules, but I guess dynamics+control and some info theory
[14:36] <edmoore> + a module on digital electronics
[14:36] <edmoore> and one on medical imaging
[14:37] Dan-K2VOL (n=dbowen1@74-132-3-136.dhcp.insightbb.com) joined #highaltitude.
[14:37] <edmoore> greetings Dan-K2VOL
[14:38] <Dan-K2VOL> Good afternoon edmoore
[14:39] <jcoxon> hey edmoore
[14:39] <jcoxon> did you just insult zeusbot?
[14:39] <edmoore> yes
[14:39] <jcoxon> hey Dan-K2VOL
[14:39] <jcoxon> hmmmm
[14:39] <Dan-K2VOL> Hi jcoxon
[14:40] <shellevil> medical imaging is fun.
[14:40] <shellevil> Especially low-cost.
[14:40] <shellevil> I looked into making a single pixel MRI scanner to measure moisture in wood.
[14:40] <edmoore> it's interesting
[14:40] <shellevil> And then you've got the neglected until recently modes.
[14:41] <edmoore> all the reconstruction techniques are good
[14:41] <shellevil> Like visible light imaging, and modes using lots of CPU, but little actual radiation/...
[14:41] <edmoore> radon transforms and the like
[14:41] <shellevil> Also - sensor fusion is going to be huge in that area.
[14:42] <Dan-K2VOL> hmm I'm stepping into the middle of this conversation, but has anyone thought about creating one of those milimeter wave scanners like they are installing in US airports?
[14:42] <shellevil> MRI+ultrasound, forex
[14:42] <shellevil> mm wave scanner + 3d modelling software + texturemaps + head-up-display = naked-vision.
[14:43] <Dan-K2VOL> hehehe
[14:43] <shellevil> ISTM that you can either do it 'properly' - with huge amounts of stuff
[14:43] <shellevil> or single pixel scanned with a dish
[14:44] <shellevil> getting time, rather than just reflectometry is going to be hard though.
[14:45] <Dan-K2VOL> gtg guys ttyl. I've created a site to publish the SNOX documentation and code, I'll be publishing the source code for the SNOX flight computer later today. It's linked at the bottom of http://spiritofknoxville.com
[14:45] <edmoore> i would really like to have a rocket payload decelerator for balloons
[14:45] <Dan-K2VOL> i have wanted that too edmoore
[14:46] <edmoore> one that uses radar/ultrasonics/something in the last 10m of descent and then triggers rockets, a la mars rovers
[14:46] <Dan-K2VOL> phoenix mars lander did it just fine
[14:46] <edmoore> exacty
[14:46] <Dan-K2VOL> open source retro-rockets
[14:46] <edmoore> dab, cool news on the new site
[14:46] <edmoore> will keep checking it often
[14:47] <Dan-K2VOL> thx will try to put up everything that may be useful
[14:47] <Dan-K2VOL> ttyl
[14:47] Dan-K2VOL (n=dbowen1@74-132-3-136.dhcp.insightbb.com) left irc:
[14:47] Action: shellevil needs to get his laser ranger finished and on ebay
[15:03] <edmoore> jcoxon: ping, though you have probably seen it
[15:04] <jcoxon> hey edmoore
[15:04] <edmoore> dan's link
[15:04] <jcoxon> the link Dan-K2VOL gave?
[15:04] <edmoore> good stuff
[15:04] <edmoore> yeah
[15:04] <jcoxon> yeah had a good luck
[15:04] <jcoxon> very interesting
[15:04] <edmoore> especially the explanation of the software system
[15:05] <edmoore> from embedded through to webpage, all as one part of the same machine
[15:05] <edmoore> quite neat
[15:05] <jcoxon> oh yes - i remember reading that during one of the flights
[15:11] <edmoore> though lots of computers floating around the place
[15:17] Matt_ (n=chatzill@87.115.163.17) joined #highaltitude.
[15:25] <jcoxon> hi Matt_
[15:25] <Matt_> hey
[15:25] <Matt_> is anyone here around the Lincolnshire area?
[15:25] <Matt_> Lincolnshire even...
[15:26] <jcoxon> umm lots of people are in cambridge
[15:26] <Matt_> well we lost a balloon payload around here yesturday
[15:27] <jcoxon> balloon payload?
[15:27] <jcoxon> you guys launched?
[15:27] <Matt_> http://www.hexoc.com/balloon/
[15:28] <Matt_> actual image of it: http://i9.photobucket.com/albums/a73/jonsowman/DSC04857.jpg
[15:28] <jcoxon> nice setup
[15:28] <jcoxon> what freq were you using?
[15:28] <rjharrison> I'm hearing a beakon
[15:28] <rjharrison> on 434.070
[15:28] <Matt_> pmr446, ch5
[15:29] <Matt_> it also has a 433 transmitter
[15:29] <rjharrison> 433
[15:29] <rjharrison> or 434
[15:29] <jcoxon> Matt_, you a radio ham?
[15:29] <Matt_> yea
[15:29] <jcoxon> what sort of power were you using?
[15:29] <jcoxon> just out of interest!
[15:30] <Matt_> its transmitting on pmr446 ch5 0.5W with a egg beater ant.
[15:30] <jcoxon> and the 433?
[15:30] <Matt_> and 433 much lower
[15:30] <rjharrison> What is pmr446?
[15:30] <jcoxon> cool
[15:30] <jcoxon> so run us through the flight - and we can see what we can do to help
[15:31] <jcoxon> where did you launch from?
[15:31] <Matt_> well we lost gps coordinates above 70000ft
[15:31] <Matt_> and when it dropped below it was way off
[15:31] <Matt_> heres the track
[15:31] <Matt_> http://weather.hexoc.com/path.JPG
[15:32] <rjharrison> Whats the data?
[15:32] <Matt_> this is the transmitter (433) http://www.rapidonline.com/Electrical-Power/Security-Warning-Device/AM-FM-System-Modules/AM-Remote-control-transmitter/32432/kw/am+transmitter
[15:32] <jcoxon> brave to launch yesterday - the JS was quite fast
[15:32] <Matt_> on 433 or 446?
[15:32] <rjharrison> Morse rtty?
[15:32] <Matt_> 446 is ax25
[15:32] <rjharrison> on 446 i assume it just a beacon on 433.070
[15:33] <Matt_> 433 is serial data
[15:33] <Matt_> 433 is every 10s
[15:33] <jcoxon> okay cool
[15:34] <jcoxon> so you lost comms after 7000ft ascent or descent?
[15:34] <jcoxon> or right
[15:34] <jcoxon> sorry i see now
[15:34] <jcoxon> yeah your gps was limited at 18km
[15:34] <Matt_> we expected it to be limited
[15:34] <jcoxon> Matt_, well you could use this http://www.srcf.ucam.org/~cuspaceflight/predict/index.php
[15:34] <rjharrison> Use a lassen or a ublox next time
[15:34] <jcoxon> to predict landing site
[15:35] <Matt_> but not for when it came back down to be 142km from the last known position!
[15:35] <Matt_> we used http://www.srcf.ucam.org/~cuspaceflight/predict/index.php
[15:35] <jcoxon> okay
[15:35] <Matt_> so can you hear the 433 beacon?
[15:35] <Matt_> where are you
[15:36] <rjharrison> Leeds
[15:36] <rjharrison> USB on 434.070
[15:36] <jcoxon> rjharrison, what freq are you tuned to?
[15:37] <Matt_> i doubt thats ours, firstly its too far north, and were transmitting on 433.92 and 466.05
[15:38] <jcoxon> Matt_, have you guys seen the UKHAS stuff?
[15:38] <Matt_> using the last known position and altitude, this is the expected path it took http://weather.hexoc.com/Capture1.jpg
[15:39] <Matt_> i havnt got a chance to have a proper look yet
[15:39] <jcoxon> :-)
[15:39] <jcoxon> most people who launch in the UK come across it
[15:40] <rjharrison> USB FM?
[15:40] <Matt_> the 433 is AM, but u can hear it on FM, the pmr446 is FM
[15:41] <Matt_> the jet stream is around the 250mb pressure area correct?
[15:41] <Matt_> about 40 000ft ish?
[15:42] <jcoxon> yeah about that
[15:42] <Matt_> as ours crossed the country at a much higher altitude
[15:43] <Matt_> when we got the first gps coordinates of it in the east, the pressure was <100mb
[15:43] <Matt_> it was probably >70,000ft altitude?
[15:44] <jcoxon> yeah
[15:44] <jcoxon> quite possibly
[15:44] <sbasuita> Matt_, did you not get the payload to Tx GPS altitude data?
[15:45] <Matt_> sometimes
[15:45] <sbasuita> Ah, right - it has an upper limit
[15:45] <jcoxon> Matt_, i see from your site you found that you can't use amateur radio at altitude
[15:45] <jcoxon> annoying isn't it
[15:45] <Matt_> yep
[15:45] <Matt_> we were going for 144.8
[15:46] <Matt_> and would probably have not lost it due to reapeaters and igates
[15:46] <jcoxon> yeah, we had good sucess with 434.075 as our freq
[15:46] <Matt_> power?
[15:46] <jcoxon> 10mW
[15:46] <jcoxon> the ofcom rules are quite strict
[15:46] <Matt_> pmr446 works fine
[15:47] <jcoxon> really?
[15:47] <Matt_> 0.5W erp
[15:47] <jcoxon> oh right , practically yes
[15:47] <jcoxon> i'm not too sure about hte legality
[15:47] <Matt_> a rsgb person said that was fine
[15:47] <jcoxon> really
[15:47] <jcoxon> now that is interesting...
[15:48] <Matt_> the only reason we lost it was we were 140km away when it got below 15000 ft
[15:48] <rjharrison> What imte was launch Matt_
[15:48] <rjharrison> time
[15:48] <Matt_> 12noon
[15:48] <rjharrison> ok so you are down somewhere
[15:48] <Matt_> yea
[15:48] <Matt_> the batteries are 13Ahr so should still be going
[15:48] <rjharrison> Well if the radios are working you should find it
[15:49] <rjharrison> What batteries did you use?
[15:49] <sbasuita> Matt_, perhaps contact the local radio society and see if you can get their members to listen out?
[15:49] <Matt_> non rechargable lithiums
[15:49] <Matt_> i shall see if i can find any local hams
[15:49] <Matt_> do u know of any?
[15:49] <sbasuita> no, sorry
[15:50] <rjharrison> Put a call out on the local repeater
[15:50] <Matt_> ok thanks
[15:50] <sbasuita> (i'm not a ham - yet! ; P )
[15:50] <Matt_> ill have a go
[15:50] <rjharrison> Matt do you want a local repeater info
[15:50] <Matt_> i was going to send packets in the aprs network
[15:51] <Matt_> however i dont seem to have the cables atm
[15:51] <Matt_> a mate has them
[15:51] <edmoore> jcoxon: yo
[15:52] <Matt_> does anyone have access to the aprs network?
[15:53] <edmoore> 13Ahr!
[15:54] <Matt_> yea
[15:54] <edmoore> Matt_: hello, my name is ed and I am from CU Spaceflight
[15:54] <Matt_> hi
[15:54] <edmoore> Have you emailed us at any point in the past? I tend to loose track
[15:54] <Matt_> possibly
[15:54] <Matt_> not me personally tho
[15:54] <edmoore> ok
[15:55] <edmoore> ok, so you re-gained telemetry on the way down
[15:55] <edmoore> after the gps kicked back in
[15:55] <Matt_> yes
[15:55] <edmoore> but you lost telemetry at 7000ft
[15:55] <rjharrison> Well good effort guys. It was a bit windy in the Jet Streams for me to launch today
[15:55] <Matt_> well about 15 000ft
[15:56] <Matt_> pressure was 500mb or so
[15:56] <Matt_> when we re-gained telemetry it was 142km away
[15:56] <edmoore> ah ok, that is quite high
[15:56] <edmoore> we could Monte-Carlo guestimate the landing site but it would have a fairly impractical standard deviation
[15:57] <edmoore> the radio is still working you say?
[15:57] <rjharrison> Get out there with the yagi and fox it
[15:57] <Matt_> yea we gave up last night and its a 3hr drive
[15:58] <Matt_> we would have done that last night but the minibus with the yagi in it had to go back
[15:58] <edmoore> I presume 9sorry if this is teaching your granny to suck eggs) you had a decent yagi?
[15:58] <edmoore> ok cool
[15:58] <rjharrison> Ok so balloon down somwhere. I host mine two weeks ago
[15:58] <edmoore> and when you say you couldn't find it - could you even hear it?
[15:58] <Matt_> when we got there it was silent
[15:58] <edmoore> right
[15:59] <edmoore> and where exactly did you go - where our predictor predicted?
[15:59] <Matt_> this is where the predictor said it may have landed
[15:59] <Matt_> http://weather.hexoc.com/Capture1.jpg
[15:59] <Matt_> thats using data from the last known position
[15:59] <edmoore> ok
[15:59] <Matt_> the predctor was accurate until it went 140km east
[16:00] <edmoore> where does the predictor say it should have gone?
[16:00] <Matt_> this is the track http://weather.hexoc.com/path.JPG
[16:00] <Matt_> the predictor reckoned about 40km north from the start
[16:01] <edmoore> ok
[16:01] <edmoore> so it's gone a lot further east than expected
[16:01] <edmoore> what descent velocity did you enter into the predictor, and how did you calculate it?
[16:01] <edmoore> once you had grabbed some telemetry on the way down, this is
[16:01] <Matt_> it covered 140km in <38mins
[16:02] <Matt_> 5m/s
[16:02] <edmoore> and that was based on a calculation done before launch
[16:02] <edmoore> ?
[16:03] <rjharrison> Market Deeping or somewhere there
[16:03] <Matt_> no i think thats what the paracute manifacutrer stated
[16:03] <edmoore> ok
[16:03] <rjharrison> Do you have any of the raw data around?
[16:03] <Matt_> yea
[16:03] <Matt_> i have it in aprs format?
[16:04] <edmoore> Matt_: did you get any descent rate/altitude pairings based off actual descenet telemetry?
[16:04] <rjharrison> Do you want to post it some where and well have a look at calculating some rates
[16:05] <Matt_> yea ill just upload the file
[16:05] <Matt_> however, the altitude from the gps wasnt working properly all day
[16:05] <rjharrison> Matt_ how old are you guys doing this
[16:05] <Matt_> so 18
[16:05] <Matt_> 18
[16:05] <rjharrison> Cool
[16:06] <Matt_> so u have to use pressure
[16:06] <rjharrison> So a young team haing some fun then
[16:06] <Matt_> were doing it as a school project
[16:06] <rjharrison> Even better
[16:06] <edmoore> Matt_: can I ask who your RSGB contact is?
[16:06] <Matt_> http://weather.hexoc.com/aprs.txt
[16:07] <rjharrison> There are a few GPS's out there that work at altitude
[16:07] <Matt_> giles read
[16:07] <Matt_> if there is a next time we hope to get one
[16:07] <jcoxon> Matt_, feel free to get involved in UKHAS
[16:07] <edmoore> indeed, there is a lot of help available here
[16:08] <edmoore> and perhaps better informed legal advice
[16:08] <Matt_> so not legal for pmr446 at hight?
[16:08] <rjharrison> Yep
[16:08] <rjharrison> It needs to stay on the ground
[16:08] <jcoxon> cya all
[16:09] jcoxon (n=jcoxon@host81-159-142-78.range81-159.btcentralplus.com) left irc: "Leaving"
[16:09] <rjharrison> There is a nice cheep 25 pound module from radiometrix which will sort you oit
[16:09] <edmoore> normally aerial use for such a thing is quite strictly exempt
[16:09] <rjharrison> about the size of a pen top
[16:09] <edmoore> Matt_: what is the format of your aprs data?
[16:09] <edmoore> which field is pressure and what is its unit?
[16:10] <sbasuita> DanielRichman, you going to write up the radio stuff from yesterday?
[16:10] <rjharrison> http://www.radiometrix.co.uk/products/ntx2nrx2.htm
[16:11] <Matt_> @140323h5249.60N/00027.30W352/000/A=000000AVDATA-IT68OT203PP1509BV2716 gps- 52.4960N, 0.2730W ...
[16:11] <rjharrison> If you do it again use one of there on 434.075
[16:11] <rjharrison> these
[16:11] <Matt_> we shall look at that next time
[16:11] <sbasuita> Matt_, ntx2
[16:12] <sbasuita> Matt_, http://www.radiometrix.co.uk/products/ntx2nrx2.htm
[16:12] <Matt_> yea ive found their website
[16:12] <edmoore> chaps, can I ask if we can keep the signal to noise ratio up so we can have a guess at where this thing might have landed
[16:13] <edmoore> Matt_: where in your APRS string is altitude, or whatever you are using to calculate altitude
[16:13] <Matt_> altitude is where is says A=xxxxxx but its normally 0000000
[16:13] <Matt_> pressure is where it says PP=
[16:13] <Matt_> but that needs converting
[16:13] <Matt_> ill post the converted vlaues
[16:14] <rjharrison> It may be best to say what the PP is in
[16:14] <edmoore> units of alt = meters?
[16:14] <rjharrison> Just in case there has been a problem with conversion
[16:14] <Matt_> alt is in ft
[16:15] <Matt_> here is the converted pressure weather.hexoc.com/pp.csv
[16:15] <rjharrison> Matt_ Have you been on here before?
[16:15] <Matt_> http://weather.hexoc.com/pp.csv
[16:15] <Matt_> nope
[16:15] <edmoore> ok. I notice that you occassionaly get good-loooking altitude values in among the 00000 values - any idea why that might be?
[16:16] <Matt_> well the gps gives A=000000 when it cannot get enough satellites
[16:16] <Matt_> however we have no idea why it could not work out pressure most of the time
[16:16] <edmoore> ok. on a balloon it should always have plenty of sattelites, all of the time, unless something is wrong
[16:16] <Matt_> also the pressure sensor has a 100mb minimium
[16:17] <Matt_> yea that suprised us too
[16:17] <edmoore> something to look at for v2, but back to the task at hand
[16:18] <edmoore> to maximise the chance of getting a good predicted landing site, we need exacty the following
[16:18] <edmoore> a lattitude, a longtitude, and an altitude in meters, all valid at a given instant
[16:19] <edmoore> 2 of the above, ideally close together, and as low in altitude as possible
[16:19] <edmoore> this way we can calculate the various drag co-efficients of your payload, and run the prediction with those accurate values
[16:20] <edmoore> it looks like you have the latitude and longitude ok, so we need to extract altitude values from your pressure data
[16:21] <edmoore> so tell me about the pressure info - units, the sensor, the method of interfacing to the microcontroller etc
[16:21] <Matt_> well the last two pressure readings are 362mb and 514.9mb
[16:22] <edmoore> ok - that's cool - and what are their associated lats and longs?
[16:23] <edmoore> and times
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[16:25] <rjharrison> oops you scared him ed
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[16:25] <Matt_> the coordinates will need converting i noticed
[16:26] <edmoore> decimal is what we need
[16:26] <Matt_> just a mo...
[16:29] <Matt_> first is 52.7994N, 0.453611W, pressure 362.2mb
[16:31] <Matt_> second is 52.833N 0.4583W pressure 514.9mb
[16:31] <Matt_> first one is 15.01 and second 2min later
[16:32] <edmoore> precisely 2 mins?
[16:32] <Matt_> 1min 59s to be exact
[16:34] <edmoore> ok cool
[16:35] <edmoore> ok
[16:35] <edmoore> what doesn't help is that the webpage with the nasa atmospheric model isn't opening for me
[16:35] <Matt_> to convert pressure to altitude?
[16:35] <edmoore> yep
[16:36] <Matt_> how accurate does it need to be?
[16:36] <edmoore> 2-3% would do
[16:36] <rjharrison> Are you going to get the gound pressure for yesterday ed
[16:37] <Matt_> at takeoff it was 988
[16:37] <Matt_> alothugh thats quite a distance away
[16:37] <rjharrison> Ideally you need to know the altitude too at launch
[16:38] <edmoore> rjharrison: probs, although it usually falls within 3% off of 101kpa
[16:38] <Matt_> 500ft
[16:38] <edmoore> basically, it *could* be the case that you have had some crappy event
[16:39] <edmoore> (what size balloon btw?)
[16:39] <edmoore> and are coming down tangled up
[16:39] <edmoore> that might explain dodgy gps
[16:39] <edmoore> and would up your descent rate quite a lot
[16:39] <Matt_> i have an image of the balloon
[16:39] <Matt_> it had about .5kg of freelift
[16:40] <edmoore> which would make a significant difference to the predicted and actual landing site from an altitude of whatever it was you entered, with a roughly estimated landing speed
[16:40] <edmoore> what size was it?
[16:40] <edmoore> an image would be good
[16:40] <Matt_> if the others were around they would know
[16:42] <Matt_> http://weather.hexoc.com/Picture1.jpg
[16:43] <Matt_> that maybe its final size, or may have had a little more helium in it after that
[16:44] <edmoore> ok
[16:44] <edmoore> 1-1.5kg
[16:44] <Matt_> well the payload was around 1.7kg
[16:44] <Matt_> and we aimed for .5kg free lift
[16:45] <edmoore> do you know where you bought it from?
[16:45] <Matt_> somewhere in america, but im not sure
[16:46] <Matt_> i need to wait for jon to get back from work
[16:47] <edmoore> ok, so those pressures are of the order of 18,000ft anyway
[16:47] <edmoore> that is very high
[16:48] <Matt_> alothuhg it fell about 15000 in 2mins i think?
[16:49] <Matt_> wait 8000 in 2min
[16:49] <edmoore> my intuition isn't up to much for that altitude, but it will be travelling pretty fast, yeah
[16:50] <edmoore> rjharrison: do you have a copy of excel?
[16:50] <edmoore> I don't on this pc, so my spreadsheet is a bit broked
[16:51] <sbasuita> edmoore, openoffice?
[16:52] <shellevil> google-docs
[16:52] <edmoore> it often breaks the maths bashing in excel
[16:52] <shellevil> google-docs is fun
[16:52] <edmoore> the drop-down box stuff
[16:58] <Matt_> would you say this prediction is fairly accurate anyway? http://weather.hexoc.com/Capture1.jpg
[17:00] <shellevil> 15 min flight?
[17:01] <sbasuita> shellevil, i assume the starting altitude is very high
[17:02] <Matt_> well its starting at 15000 or so and falling at 5m/s
[17:02] <Matt_> ft that is
[17:02] <sbasuita> Matt_, why did you choose to log in feet?
[17:02] <Matt_> the gps sends it ft
[17:02] <sbasuita> : O
[17:03] <sbasuita> Matt_, which gps you using?
[17:03] <edmoore> Matt_: it's meaningless to say so one way or the other
[17:03] <Matt_> http://www.pocketgpsworld.com/globalsat-br355-gps-review.php
[17:03] <shellevil> Matt_: oh - I was assuming it was a normal flight
[17:03] <edmoore> a prediction is only as good as the information you give it
[17:04] <edmoore> if you don't give it a good descent rate, it won't be any good as a prediction
[17:04] <Matt_> well i made a few assumsions but 5m/s is about right for the parachute we have
[17:04] <shellevil> And a 40Km or so range prediction can easily be out by 4Km, even in good conditions.
[17:04] <edmoore> sure - if it's all gone to plan then that is probably good enough
[17:04] <edmoore> certainly you should hear it
[17:04] <edmoore> but
[17:05] <edmoore> infact, was the alt data dodgy on the way up too?
[17:05] <edmoore> suggesting not enough sats
[17:05] <edmoore> or just on the way down?
[17:05] <Matt_> up and down
[17:05] <edmoore> ok
[17:05] <Matt_> and by dodgy more just non existant
[17:05] <edmoore> that is very puzzling
[17:06] <Matt_> it maybe its placement in the box
[17:06] <edmoore> I assume it worked fine in gorund testing as part of the payload?
[17:06] <Matt_> yea
[17:06] <edmoore> well, you of course tested it thoroughly for several hours in flight configuration on the ground, didn't you....
[17:06] <Matt_> yes
[17:06] <edmoore> so it shouldn't be its placement in the box then
[17:06] <edmoore> assuming that placement worked fine when you tested it
[17:07] <Matt_> i assume it was in the same place
[17:07] <Matt_> i cant say i put it in
[17:07] <edmoore> assume makes an ass out of you and me etc
[17:07] <edmoore> but yeah, fair enough
[17:07] <Matt_> it was in the same sorta place tho i know that
[17:08] <Matt_> we still have pressure anywya
[17:08] <edmoore> as long as the antenna can see sky, it should be fine
[17:08] <edmoore> and it's well shielded from other stuff
[17:09] <Matt_> well tbh i dont think the gps was in the box much during testing
[17:09] <Matt_> but it was sometimes, and never had these problems previously
[17:09] <edmoore> how did you find out about UKHAS?
[17:10] <Matt_> google search for balloon society or something similar
[17:11] <edmoore> when was this?
[17:12] <Matt_> eailier 2day
[17:12] <edmoore> but to summarise: you need to hunt the predicted area with a yagi - with such a powerful radio onboard you should be able to at least hear something if it is still transmitting
[17:12] <edmoore> then you can track it down
[17:13] <Matt_> yea
[17:13] <edmoore> if it has died, finding it blind will be hard work with so little descent data
[17:13] <Matt_> we cant do it as were now too far away
[17:13] <edmoore> we have found stuff before when it went dead at 3km, but not 15km
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[17:13] <Matt_> alothugh we hope someone will some accross it
[17:14] <Matt_> the area is flat with large fields
[17:15] <Matt_> do your gps modules have the 70000ft+ limit on them?
[17:15] <shellevil> some do, some don't
[17:15] <shellevil> there is a list on the wiki of those that don't
[17:16] <Matt_> ok thanks
[17:16] <Matt_> have u ever had any travel 140mph+ above 60-70000ft?
[17:17] <edmoore> Matt_: we use the Lassen iQ
[17:17] <edmoore> Matt_: yes - it falls pretty fast initially
[17:17] <edmoore> Matt_: the ublox 5 chipset will aslo work - an example gps that uses it is the GS406
[17:17] <Matt_> i didnt mean fall that fast
[17:17] <Matt_> travel laterally that fast
[17:18] <edmoore> that's entirely possible in a strong jetstream
[17:18] <Matt_> yet stream at that altitude?
[17:18] <edmoore> but we would never launch into a jet stream that fast
[17:18] <Matt_> jet
[17:18] <edmoore> it can be high all the way up
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[17:18] <edmoore> however, we have never (nor would) launch intoa jetstream that fast
[17:18] <edmoore> it is possible of course your gps is wrong
[17:18] <edmoore> seeing as it seems to be struggling a worrying amount
[17:19] <Matt_> i did think that, but it seems unlikely as we picked up few packets where we were, so it had moved a fairdistance
[17:19] <Matt_> also we got at least 6 packets from the east of the country
[17:20] <Matt_> we used this forecast for jet stream http://www.metcheck.com/V40/UK/FREE/jetstream.asp
[17:21] <Matt_> i dont have yesturdays forecast with me but it didnt show strong wings
[17:21] <Matt_> winds
[17:21] <sbasuita> Matt_, i'm pretty sure the cambridge predictor uses jet stream forecasts
[17:21] <Matt_> we used that, and it never suggested it would travel east nearly that much
[17:22] <sbasuita> Matt_, there's always the possibility that the forecasts were just plain wrong ;)
[17:22] <Matt_> well yea
[17:23] <Matt_> but the odd thing is that when it went 140mph+ it was well outside of jetstream altitudes
[17:23] <Matt_> and we had no idea as the gps was too high
[17:25] <edmoore> sbasuita: improbably
[17:25] <edmoore> our predictor uses the GFS model
[17:25] <edmoore> it uses the most up to date data that is available for a given prediction
[17:26] <edmoore> if you ran it just before launch, the data would have come out within the last 6 hours
[17:26] <edmoore> that's close enough to be pretty good
[17:26] <Matt_> the balloon was following the prediction for the first part of the journey (i assume uve all seen our track)
[17:27] <edmoore> the GFS model gives you data from sea level to over 30km
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[17:27] <edmoore> Matt_: did you pick it up again at about the time you predicted you should?
[17:28] <Matt_> we didnt really have a prediction of when it would fall back into range
[17:29] <Matt_> alothugh the whole flight lastest longer than predicted i think
[17:31] <edmoore> was the ascent rate as you assumed?
[17:33] <Matt_> i think it may have been a bit slower which would explain the time taken
[17:34] <edmoore> sure
[17:34] <edmoore> ok
[17:34] <edmoore> well that's odd that it differed so much
[17:34] <edmoore> right, afraid i need to go. will be back later
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[17:34] <Matt_> ok thanks
[17:41] <Matt_> ok i have to go now, thanks for everything
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[17:47] <DanielRichman> Success! Generating 0.94 and 1.24v for the transmitter using fixed resistors
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[18:06] <rjharrison> DanielRichman Cool
[18:06] <rjharrison> That's the way I do my RTTY
[18:07] <rjharrison> seemed the easiest way
[18:07] <DanielRichman> yeah. was a bit of a pain using a 5v board, but meh
[18:07] <rjharrison> They all had me using PWM to generate the different voltages
[18:07] <DanielRichman> In other news... Xorg appears to have a memory leak in jaunty
[18:07] <rjharrison> But I thought two fixed resistors was the easiest
[18:08] <rjharrison> Oh dear
[18:08] <rjharrison> BTW if you are intrested in some simple avr C code then there is a link on my website
[18:09] <rjharrison> http://www.robertharrison.org/index.php?option=com_content&task=view&id=28&Itemid=78&mosmsg=Item+successfully+saved.
[18:09] <rjharrison> Opps
[18:09] <rjharrison> http://www.robertharrison.org/index.php?option=com_content&task=view&id=28&Itemid=78
[18:09] <DanielRichman> speaking of code... is the distributed tracker server code available?
[18:10] <rjharrison> This passes the NMEA data and sends rtty. There are a few comments in there should you want to browse
[18:11] <DanielRichman> cool. Everything we have so far is here: http://code.google.com/p/alien-flightcomputer/source/list
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[19:07] <rjharrison> Yo ed
[19:07] <rjharrison> quick elec question
[19:08] <rjharrison> iQ likes it's RX Pins pulled high when not used
[19:09] <rjharrison> I use a single 700R connected to vcc and then to both rx on the iQ
[19:09] <rjharrison> I assume that should be fine and is the same as adding on to each of the pins
[19:10] <rjharrison> adding one
[19:10] <rjharrison> the iQ has two rx pins rx1 rx2 for anyone else out there
[19:14] <edmoore> rjharrison, sorry for slow reply, irc client didn't ping
[19:15] <edmoore> um, that presumably means both RX are connected to a common tx from the micro
[19:15] <edmoore> check that it won't get upset if both Rx receive the same message
[19:16] <rjharrison> The rx on the lassen are used I guess to programm it
[19:16] <rjharrison> I can't imagin why you woudl send data to it other than that
[19:17] <rjharrison> The sheet says that they need to be pulled high and not left floating if not in use
[19:17] <rjharrison> so I have pulled then high off one resistor
[19:18] <edmoore> sure yes
[19:18] <edmoore> but if you have pulled them both high with the same resistor (which probably wants to be more like 10k incidently) then I presume that means both rx are electrilly conneced
[19:18] <rjharrison> The interesting thing is that I would like to be able to program the lassen iq from the board
[19:19] <edmoore> which means that they will both get the same message if you tx data to the lassen from the avr
[19:20] <rjharrison> OK will they work still if they are pulled high
[19:20] <rjharrison> Thats cool
[19:20] <edmoore> sure
[19:20] <rjharrison> In fact the right answer
[19:21] <rjharrison> I see what you mean now
[19:21] <edmoore> well that's the thing, I don't know. my thinking is that it might be a problem if both rx's get the same message at the sae time
[19:21] <rjharrison> if they are connected then I will send data to both
[19:21] <edmoore> yeah
[19:21] <rjharrison> I'll change that then
[19:21] <edmoore> well, i don't actually know if it's a problem, that's the thing
[19:21] <edmoore> it just strikes me that it's the sort of thing that could be, depending on how the lassen's firmware works
[19:22] <edmoore> we haven't run into the problem as we just completely ignore one of the lassen's uarts
[19:22] <rjharrison> Well for the 2p cost of the R i'll drop another in
[19:22] <edmoore> probably sensible
[19:23] <rjharrison> Don't you pullup the RX on the other line. BTW what do you send to the GPS
[19:23] <rjharrison> The data sheet says no fix if not pulled up
[19:24] <edmoore> the data sheet lies :)
[19:24] <edmoore> we put it in tsip mode
[19:24] <edmoore> and you can tell it to restart and so on
[19:25] <rjharrison> Oh cool
[19:25] <rjharrison> I should have a look at that at some point
[19:25] <rjharrison> I'm too trusting
[19:25] <rjharrison> 70k pullup
[19:25] <rjharrison> not 700R
[19:25] <rjharrison> I lied
[19:26] <rjharrison> between 1K and 100K
[19:26] <edmoore> yep, much better
[19:27] <edmoore> the idea behind pull-up/down is to stop static and other crap building up and giving a false triggering on a line
[19:27] <edmoore> it gives the static a route to discharge through
[19:27] <rjharrison> OK cool
[19:27] <edmoore> so it can be pretty big because you're not talking much current
[19:27] <edmoore> too small and you start getting needlessly large currentls flowing
[19:28] <rjharrison> I assum when you send data its at vcc for high then
[19:28] <rjharrison> and at vcc-R for low
[19:28] <edmoore> UARTS ARE ACTIVE LOW
[19:28] <edmoore> whoops
[19:28] <edmoore> so you take the line low to do stuff
[19:28] <edmoore> and it's high when it's just sitting arund doing nothing
[19:29] <rjharrison> Ok so can I still program the RX if it is pulled high all the time through the R
[19:29] <rjharrison> I need to hear that again
[19:30] <edmoore> those details should all be transparent - the uarts on the avr are set up corretly, as are the ones on the gps
[19:30] <edmoore> unless you're doing something cunning on the same bus
[19:30] <edmoore> oh sorry yes, i understand your question now
[19:30] <edmoore> yes you can
[19:32] <rjharrison> Well I don't currently connect the RX on the iQ to anything so I just pull it up as per the instructions. But now I would like to use it to program the iQ when it's on the ground. If I have linked this to VCC via the R then i guess I can't send data on it.
[19:33] <edmoore> no - because it's not connected to vcc in an electrical sense - there's a resistor in the way
[19:33] <edmoore> and one with a big value
[19:33] <rjharrison> Ok thanks dealing with my total lack of knowledge
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[19:34] <rjharrison> Yep the R will keep the v very low even though it is called being pulled high
[19:34] <rjharrison> Hi DanielRichman Had a lok at the code very nice and clean
[19:35] <DanielRichman> rjharrison, :)
[19:35] <DanielRichman> It's not fully tested yet... I know messages.c, radio.c works but that's about it ;)
[19:35] <rjharrison> But it reads nice
[19:35] <edmoore> rjharrison: http://www.seattlerobotics.org/encoder/mar97/basics.html
[19:35] <rjharrison> Feel free to dig around in my code and take what you like
[19:36] <DanielRichman> cool, thanks. I will do
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[19:37] <rjharrison> Thanks edmoore perfect example
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[19:40] <jcoxon> hey Matt_
[19:40] <Matt_> hey
[19:40] <jcoxon> any sucess?
[19:40] <Matt_> none yet
[19:40] <Matt_> i have the details of the balloon and stuff now, i know someone was asking beofre
[19:40] <jcoxon> hmmm, we've all lost payloads - it suchs
[19:40] <jcoxon> sucks*
[19:40] <Matt_> yea
[19:41] <Matt_> an idea we got from some1, is to put a sms transmsitter on, and when it lands, send a text of its location
[19:42] <jcoxon> yes, thats used a lot
[19:42] <jcoxon> definitely helps - increases the cost but helps a lot when the payload is on the ground and radio isn't as good
[19:42] <Matt_> do u not use it?
[19:42] <jcoxon> i do
[19:42] <DanielRichman> Matt_, we're gonna do that on our payload
[19:42] <jcoxon> i use a GM862 GSM module to send sms
[19:42] <DanielRichman> Using sbasuita's old phone
[19:43] <Matt_> ye i hear they have serial ports on the bottom
[19:43] <Matt_> old phones
[19:43] <edmoore> yep
[19:43] <edmoore> a 1hz radio beacon is another solution
[19:43] <DanielRichman> well, yeah but it's a pain to solder to them directly. If you're lucky, even for a new phone, you can get a USB cable for it that supports serial, chop the end of and use the wires you need
[19:44] <edmoore> some redundant sstem helps, basically
[19:44] <Matt_> yea
[19:44] <Matt_> we had a redundant 433 transmitter
[19:44] <Matt_> low power
[19:45] <Matt_> another guy who was doing the project is around now too
[19:45] <jcoxon> oh cool
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[19:46] <Matt_> hey jon
[19:46] <Jon__> hi all
[19:46] <Jon__> I'm part of the team that launched yesterday, lost it near Lincoln
[19:47] <jcoxon> Jon__, hi
[19:47] <edmoore> hi Jon__ sorry to hear that
[19:47] <Jon__> i've read the conversation Matt had on here earlier
[19:48] <jcoxon> Jon__, yeah we were just trying to get an idea of the situation
[19:48] <edmoore> we rarely get groups whove gone from idea to launch in the UK without any of us hearing about it :)
[19:48] <Matt_> weve emailed u before i think
[19:49] <edmoore> who would have emailed?
[19:49] <Jon__> Ben Oxley
[19:49] <edmoore> I'll have a look - we get an awful lot nowadays
[19:49] <Jon__> give me two minutes, i'll find a copy of the emails
[19:49] <edmoore> sutton grammar school
[19:49] <edmoore> gotcha
[19:49] <Jon__> that's the one
[19:50] <edmoore> Henry Hallam answered - an explained the radio legalities
[19:50] <Jon__> that's correct
[19:50] <jcoxon> okay, so from the prediction you guys ran yesterday you got a potential landing site - but on landing no radio sounds?
[19:51] <Matt_> we didnt hear anything when we were up there
[19:51] <Matt_> but that predition i ran was when we got back
[19:51] <Matt_> but we were fairly near the prediction
[19:51] <jcoxon> oh okay
[19:51] <jcoxon> hmmm, did it have a message on it about if found and a number to call
[19:52] <Matt_> yea
[19:52] <Jon__> yes
[19:52] <Jon__> names, telephone numbers, and a monetary reward notice
[19:52] <edmoore> you had a 0.5W radio onboard so you would probably have heard *something* if you were at all close
[19:52] <edmoore> pointing to the radio being off
[19:52] <Matt_> this is the prediction were talking about i assume
[19:53] <Jon__> that is possible
[19:53] <Matt_> we were in one of the rings at least
[19:53] <Matt_> http://weather.hexoc.com/Capture1.jpg
[19:53] <edmoore> was your antenna stiff?
[19:53] <Matt_> also the ant. could have been damaged
[19:53] <Jon__> garden wire
[19:54] <Jon__> its very springy
[19:54] <Matt_> also .5W is alot, but if its in a ditch its not gonna b heard
[19:55] <Matt_> no line of sight means the range is very low
[19:55] <Jon__> i seem to remember hearing 446Mhz is absorbed a lot by buildings
[19:55] <Matt_> we tested this with ants on cars and driving around
[19:55] <Jon__> much more so than 2m
[19:56] <jcoxon> i'm not sure there is much more you can do
[19:56] <jcoxon> try the local repeater and then just wait
[19:57] <jcoxon> i've got payloads back a lot later
[19:57] <jcoxon> a farmer found one in a field
[19:57] <edmoore> correct, if it's ina ditch there's not much you can do
[19:57] <edmoore> us too
[19:57] <edmoore> we had one wash up in denmark
[19:57] <jcoxon> edmoore, hehe i remember lanching that one
[19:57] <edmoore> my advice - you've made a balloon flight - congrats, it's a big achievement
[19:57] <Matt_> well at least we can be sure its not in the see
[19:57] <Matt_> sea
[19:58] <edmoore> start work on v2. I'm sure there are a whole bunch of things you would change now. and you have our collective experience at your disposal
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[19:58] <edmoore> afternoon Dan-K2VOL
[19:58] <Matt_> yea thanks, the actual launch and tracking went without problem
[19:58] <edmoore> i very much enjoyed Mike Coffey's software explanaion
[19:58] <Dan-K2VOL> Hi Edmoore
[19:58] <Dan-K2VOL> I'll tell him, he did a nice detailed narrative
[19:59] <Dan-K2VOL> I just got the flight computer code up as well
[19:59] <edmoore> ah grand
[19:59] <edmoore> although it's for a PIC
[19:59] <edmoore> which is a wierd religion I don't understand
[20:00] <Dan-K2VOL> haha even better, it's in BASIC
[20:00] <Dan-K2VOL> do you use AVRs?
[20:00] <edmoore> Dan-K2VOL: I particularly like the way he described the whole thing as one big machine
[20:00] <edmoore> from PIC for fedora-core server
[20:00] <Matt_> us? PICs
[20:00] <edmoore> Dan-K2VOL: ARM
[20:00] <edmoore> ARM7
[20:00] <Dan-K2VOL> ah gotcha
[20:00] <jcoxon> Matt_, Dan-K2VOL's team nearly got a balloon across teh atlantic
[20:00] <edmoore> more power than is needed, but lets you run FAT32 libraries for SD cards and the like without breaking a sweat
[20:00] <jcoxon> hold the record for the longest distance travelled
[20:01] <Matt_> awesome
[20:01] <Dan-K2VOL> what group are you in Matt_?
[20:01] <Matt_> balloon group?
[20:01] <jcoxon> Dan-K2VOL, Matt_ launched yesterday in UK
[20:01] <edmoore> Dan-K2VOL: there's some fun research floating around about how they can read off SD cards which have been in salt water for several months
[20:01] <jcoxon> school team
[20:01] <Dan-K2VOL> yes, edmoore, we sure wished we could do things like floating points and FAT32 many times
[20:01] <jcoxon> unfortunately they lost contact on its descent
[20:02] <Matt_> it got carried 140km in 38 mins above gps range
[20:02] <Dan-K2VOL> Matt_ nice, are you guys going to fly again?
[20:02] <jcoxon> Matt_, the JS was vicious yesterday
[20:03] <Matt_> its the JS above 70000ft, and below 100mb pressure?
[20:03] <Jon__> we have exams and things to think about, but it's certainly something I'd like to do again
[20:03] <jcoxon> Jon__, defintiely go for it
[20:03] <Matt_> we would build v2 with funding and time
[20:04] <jcoxon> your payload looked very good
[20:04] <Matt_> yea, everything worked fine
[20:04] <Matt_> just unlucky
[20:04] <jcoxon> though i'm intrigued about this GPS
[20:04] <jcoxon> reporting alt in feet
[20:04] <Matt_> about that
[20:04] <Dan-K2VOL> the jet stream is usually between 30 and 50,000 ft
[20:05] <Jon__> that was misinformation on matt's part
[20:05] <jcoxon> oh right :-)
[20:05] <Matt_> it reports in m and the linux module converts :\
[20:05] <Jon__> the GPS outputs in metres, the flight computer software converts to feet
[20:05] <jcoxon> fair enough
[20:05] <jcoxon> interesting we often leave it in M
[20:05] <Jon__> the reason: the tracking software plots altitude, but requires it transmitted in FT
[20:06] <jcoxon> fair enough
[20:06] <Dan-K2VOL> we used to convert M to FT onboard when we had a lot of local hams tracking
[20:06] <Matt_> what frequency did u do that on?
[20:06] <Jon__> i believe the APRS posrep format requires alt in ft
[20:06] <Jon__> don't quote me on that, though
[20:06] <jcoxon> Jon__, yeah we don't use APRS as you can't make use of the system in the uk
[20:07] <Dan-K2VOL> here's a nice site that gives you updates often on the Jet Stream: http://squall.sfsu.edu/crws/jetstream.html
[20:07] <jcoxon> instead we are making our own tracker system
[20:07] <jcoxon> with multiple listeners and a single server
[20:07] <Jon__> fair enough
[20:07] <jcoxon> e.g. http://spacenear.us/tracker/
[20:07] <jcoxon> if you guys launch again you are welcome to use it
[20:07] <Jon__> we are only using the APRS format because it checked all our boxes, and we could use existing software
[20:08] <edmoore> Jon__: we're reasonably sure that the radio system you used in this flight isn't within the law
[20:09] <Jon__> you may be correct, i'm not entirely sure either
[20:09] <edmoore> It's something we've looked into quite often, as you can imagine
[20:09] <Jon__> Yes that's true
[20:10] <Jon__> would you recommend 434 for v2 then?
[20:10] <Jon__> I'm pretty sure I even told the CAA about PMR446
[20:11] <Matt_> i assume u have to use yagis on the ground all the time?
[20:11] <Matt_> also it must be cheaper
[20:11] <rjharrison> about 25 quid for the module
[20:11] <jcoxon> yeah 434.075 10mW is our choice
[20:11] <jcoxon> radiometrix ntx2 modules
[20:11] <edmoore> Matt_: not at all
[20:11] <jcoxon> but also there is 868.69 at 500mW
[20:11] <rjharrison> and it works for about 300 miles
[20:12] <edmoore> we can hear it from several hundred km away with a whip antenna
[20:12] <edmoore> with just 10mW
[20:12] <edmoore> but, you can't use your APRS
[20:12] <Matt_> i assume this is all erp?
[20:12] <jcoxon> yup
[20:12] <edmoore> instead something much slower - we usually use 50baud RTTY
[20:12] <Dan-K2VOL> why not 45.45 baud edmoore?
[20:12] <edmoore> think the scrolling text in a cold-war film
[20:12] <rjharrison> http://www.radiometrix.co.uk/products/ntx2nrx2.htm
[20:12] <edmoore> Dan-K2VOL: it's not 1928 anymore :p
[20:13] <Matt_> do u build ur own 'modem'?
[20:13] <Dan-K2VOL> haha
[20:13] <edmoore> the shifting thing is quite intollerant of errors, to give a proper answer
[20:13] <rjharrison> No its v simple
[20:13] <Matt_> are there detials on your wiki?
[20:13] <DanielRichman> get receiver, plug audio out into computer, install fldigi
[20:13] <Dan-K2VOL> what is the difference in shift between 45 and 50 baud?
[20:14] <edmoore> i mean baudot vs ascii
[20:14] <jcoxon> right i''m really off
[20:14] <jcoxon> cya all
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[20:14] <edmoore> for baudot you shift into one of two character spaces
[20:14] <edmoore> whereas ascii just has the same space for all of them
[20:15] <edmoore> we do it that way round because almost all software can do 50-baud ascii
[20:15] <edmoore> that said, my radio has a built-in rtty decoder than will only do 45 baudot
[20:15] <edmoore> it is kind of arbitrary, truth be told
[20:16] <edmoore> i think we're going to try 300baud soon anyway, with FEC
[20:16] <Jon__> fair enough
[20:16] <Dan-K2VOL> yeah
[20:16] <Jon__> this is certainly something to explore for V2
[20:16] <Dan-K2VOL> we had a heck of a challenge doing everything in the 5bit RTTY
[20:16] <Dan-K2VOL> ascii would be much better
[20:17] <edmoore> all the software modems we've seen are quite happy with ascii, so we went with that in the end
[20:18] <edmoore> I am revising so very badly at the moment. I hate exams.
[20:20] <Jon__> So do I
[20:20] <edmoore> A-levels?
[20:21] <Jon__> Indeed
[20:22] <edmoore> good luck
[20:22] <Jon__> Thanks! You too
[20:22] <Matt_> well at least now we'll have time to revise :)
[20:23] <edmoore> build v2 chaps
[20:23] <edmoore> you've got good data points from v1
[20:23] <edmoore> which linux computer did you use?
[20:24] <Jon__> it's an ARM based machine, the TS-7260 from technologic systems
[20:24] <Jon__> runs Debian for ARM
[20:25] <Jon__> 2.4.26 kernel, that's either Woody or Sarge, can't remember
[20:25] <edmoore> ah, the ep9302
[20:25] <Jon__> Cirrus proc, yep
[20:25] <edmoore> we were assessing that for our next flight computer - it has an FPU
[20:26] <edmoore> but not with an OS
[20:26] <edmoore> in the end though, the ARM7 is barely doing anything so an ARM9 would probably be more hassle than it's worth
[20:26] <Jon__> it had a tendency to need a power cycle before it would boot, but that's probably something to do with a hacked bootrom
[20:28] <edmoore> our flight computers are coded onto the bare metal - we have a 5kB real time operating system. It's very simple but you can contain every process it's doing within your head, which makes debugging a little easier
[20:28] <edmoore> Dan-K2VOL: thanks or sharing the code. Looks like a well designed PCB too
[20:29] <Jon__> i toyed with the idea of an RTOS
[20:29] <Jon__> unfortunately both knowledge and time were limiting factors
[20:29] <edmoore> on something like an ARM9 its a bit job
[20:29] <edmoore> translation lookasside buffers and stuff to worry about
[20:29] <shellevil> I will note that http://www.bifferos.com/ is _WAY_ overkill - but maybe just suitable owing to its cheapness
[20:29] <shellevil> 486/133 - 26 quid, and a watt
[20:29] <edmoore> the ARM7s are much more microcontrollery - just one single address space, running code from the flash
[20:30] <shellevil> and USB
[20:31] <Jon__> for what it was, the TS-7260 was brilliant
[20:31] <edmoore> Dan-K2VOL: I'd be very interested to talk to you about thermal stability and float altitudes at some point
[20:31] <edmoore> perhaps once my exams are out the way and I can concentrate a little more
[20:32] <DanielRichman> shellevil, that bifferboard looks intense -- so cheap for something like that with linux. Perhaps for our v2
[20:32] <shellevil> DanielRichman: its problem is lack of GPIO
[20:32] <edmoore> Linux
[20:32] <edmoore> isn't
[20:32] <edmoore> necessarily
[20:32] <edmoore> cool
[20:32] <edmoore> .
[20:32] <shellevil> DanielRichman: but OTOH - you can get a 44KHz A/D for 1.50.
[20:33] <shellevil> (dealextreme USB soundcard)
[20:33] <DanielRichman> hmm
[20:33] <rjharrison> Laters all and greets Dan-K2VOL
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[20:33] <shellevil> If it had the outputs of http://www.tincantools.com/ it'd be awesome.
[20:34] <shellevil> ((A DIP40 ARM board, with SD, I2C, LCD bus)
[20:34] <DanielRichman> Hmm. I want to SSH into my balloon
[20:34] <shellevil> And yes, linux can be dramatic overkill.
[20:35] <Matt_> we used linux this time, but V2 wouldnt
[20:35] <shellevil> But when writing a GPS->GPRS tracker can resolve to one-line of shell-script, ...
[20:36] <edmoore> can't argue
[20:36] <edmoore> for hobble, there will need to be quite a lot of processing
[20:37] <edmoore> I am looking at a beagleboard
[20:37] <DanielRichman> Grrr... Xorg is such a pain!
[20:37] <shellevil> beagleboard is cool.
[20:37] <edmoore> but we'll have the badgerboard for all the real time management
[20:37] <shellevil> you can do realtime with linux.
[20:37] <shellevil> But that's no longer 'vanilla'.
[20:38] <edmoore> when I looked into it (not that heavily) it looked a bit bodgy
[20:38] <edmoore> more like its arm was being twisted into RT
[20:38] <edmoore> the badgerboard is designed to do RT balloon stuff anyway, it's what it's good at. May aswell use it
[20:39] <shellevil> Sure.
[20:43] <Matt_> well we still have an almost full helium canister that needs using
[20:43] <Matt_> ideas?
[20:43] <edmoore> v2
[20:43] <Matt_> i dont think we have that long b4 the cylinder needs to go back
[20:43] <Jon__> :p
[20:44] <Matt_> how long jon?
[20:44] <Jon__> not sure
[20:44] <Matt_> although not long?
[20:44] <DanielRichman> Investigate how much helium you can be breathing before it's unhealthy, then saturate your school with as much as possible
[20:47] <Matt_> apparently the high voice is caused by having helium inside ur throat and none outside (mayb wrong)...
[20:47] <Matt_> so if the air has alot of helium in it ur voice wont change
[20:47] <Matt_> whichj is a shame
[20:47] <edmoore> Jon__: what size balloon did you use?
[20:48] <DanielRichman> Well... You could fill teachers' cars with helium, so they'll breathe it inside but when they get out.... ;)
[20:48] <Jon__> its the KCI1200 sounding balloon from Kaymont
[20:48] <Jon__> 1.8m release diameter
[20:49] <edmoore> cool
[20:51] <Jon__> seemed to be the most appropriate
[20:51] <shellevil> Matt_: it will change if the air has helium in it
[20:51] <edmoore> indeed
[20:52] <shellevil> Matt_: The tone of the voice is set by the frequency of oscillation of the vocal cords and assorted structures inside the throat.
[20:52] <edmoore> it's a somewhat arbitrary decision often, on which balloon to use
[20:52] <shellevil> Matt_: this is altered by the helium having a _much_ higher speed of sound than air.
[20:52] <Matt_> oh ok
[20:52] <shellevil> Matt_: so it effectively makes the throat shorter.
[20:52] <shellevil> Matt_: also - quite a few people have been killed by attempting things with helium.
[20:53] <Matt_> i remember who told me what i though tho ... ...jon....
[20:53] <Jon__> er that was definitely Ben
[20:53] <Matt_> yea i never had the intention of opening the canister in a room
[20:53] <shellevil> Your body interestingly has no sensors for oxygen, just CO2. In an environment with no oxygen at all, the oxygen already dissolved in the blood comes out and spews out of the lungs.
[20:53] <Matt_> and jon you can only say that as he isnt here, i bet he wont agree
[20:54] <shellevil> And you don't get any warning at all in the 3-10 seconds that you feel wierd before blacking out.
[20:54] <Matt_> yea, so bad idea
[20:54] <shellevil> unless you are _very_ careful :)
[20:54] <edmoore> chaps v2, v2, v2, v2
[20:55] <edmoore> do you have single sided pcb manufacturing facilities?
[20:55] <Jon__> Yes
[20:55] <Matt_> we need money :p
[20:55] <Matt_> double sided too
[20:55] <Matt_> and smd
[20:55] <edmoore> http://web.me.com/dbowen1/Spirit_of_Knoxville_Published_Information/SNOX_DOCS_Blog/Entries/2009/4/26_Flight_Computer_Source_Code.html
[20:55] <DanielRichman> You have double-sided and smd facilities at your school?
[20:55] <edmoore> that pcb made it very close to getting a balloon across the atlantic
[20:56] <edmoore> running a ballasting system to maintain altitude too
[20:56] <Jon__> brilliant :D
[20:56] <edmoore> with an EM406 gps (works at altitude), a £4 micrcontroller, and a few passive components, you'll be up and running again
[20:57] <edmoore> sorry, very definitely not an EM406
[20:57] <edmoore> a Lassen iQ is what I meant to say
[20:57] <Jon__> how much £ are we looking for one of those
[20:57] <edmoore> http://www.sparkfun.com/commerce/product_info.php?products_id=163
[20:57] <edmoore> camera off ebay
[20:57] <Matt_> yea i recon if we do a very light pcb we could use normal balloons, little helium, plastic bag paracute, making a very cheap / light solution
[20:57] <Jon__> radio TX?
[20:57] <edmoore> £45 for a 1.5kG balloon
[20:58] <edmoore> £10 from radiometrix
[20:58] <edmoore> ukhas is set up to listen to it for you
[20:58] <edmoore> we have the distributed listener
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[20:58] <edmoore> it's like APRS but designed for balloons
[20:58] <edmoore> + run by ballooners
[20:58] <Matt_> what frequency does that work at?
[20:58] <Jon__> any info/documentation on that?
[20:58] <edmoore> 434.whatever
[20:58] <Matt_> ok
[20:58] <edmoore> 434.075 mhz are the radiometrix modules you want
[20:59] <Matt_> so not the 0.5W 800mhz ones?
[20:59] <edmoore> a) illigal
[20:59] <edmoore> b) power hungry
[20:59] <edmoore> c) no one has listeing equipment on 800Mhz
[20:59] <edmoore> you want the NTX2
[20:59] <Matt_> 868 or whatever?
[20:59] <Jon__> 434 it is, then
[20:59] <edmoore> antenna on the balloon should be a 1/4 wave with radials
[21:00] <edmoore> pointing downwards
[21:00] <edmoore> or a 'slimjim' or J-pole - any of them will do
[21:00] <edmoore> a payload box made from polystyrene
[21:00] <edmoore> and gaffa tape
[21:00] <edmoore> 30 mins work
[21:00] <Matt_> what to do for balloon?
[21:00] <Matt_> how much would this weigh
[21:00] <edmoore> get a 1.5kG one
[21:00] <Jon__> Summer project after exams, I think
[21:01] <edmoore> you want to talk to a chap called Steve Randell - he is on this channel
[21:01] <edmoore> but not right now
[21:01] <edmoore> he imports them from the US
[21:01] <Matt_> the expenise i can see is the helium and balloon
[21:01] <edmoore> if you can come to cambridge, one of those gets simplified
[21:01] <Matt_> helium?
[21:02] <edmoore> yes
[21:02] <Jon__> We can get to cambridge very easily
[21:02] <edmoore> well we have a launch site and helium
[21:02] <Matt_> and u have a permit to lanuch?
[21:02] <Jon__> Getting another launch permit won't be a problem
[21:02] <edmoore> yep, we have a more or less permenant one
[21:03] <Matt_> alothugh u are nearer to the sea
[21:03] <Matt_> so i assume choose a good day
[21:04] <edmoore> correct
[21:04] <Matt_> brb
[21:04] <edmoore> we sort of hat the luxury of being able to go faster with a bigger balloon and still get to some given altitude
[21:06] <Jon__> Well we will certainly give this another go, but it's going to have to wait a couple of months
[21:08] <Jon__> I have to be going now
[21:09] <Jon__> thanks all for your help everyone
[21:09] <Jon__> i'm sure i'll be speaking to you soon, asking for advice for V2!
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[21:15] <DanielRichman> Xorg has bloated 200mb (RAM) even though nothing has changed about the processes running.
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[21:20] <shellevil> x can be asked to cache images
[21:20] <shellevil> google xrestop
[21:20] <shellevil> which can bloat
[21:22] <DanielRichman> interesting.
[21:23] <DanielRichman> biggest one is compiz, using 12mb
[21:23] <DanielRichman> anyway to get it drop caches? short of starting metacity?
[21:24] <shellevil> dunno
[21:24] <DanielRichman> and #ubuntu seems to be a massive spamfest, so doubt I'll get response out of that
[21:27] <DanielRichman> hmm. time to disable fglrx and see what happens
[21:28] <DanielRichman> be right back
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[21:37] <DanielRichman> Arrgh. It's fglrx that's doing it. What a piece of sh*t
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[22:04] <Laurenceb> hello folks
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[22:31] <shellevil> hlo
[22:31] Action: shellevil sighs at boring stuff eating into hacking time.
[22:32] <shellevil> Been repairing sofa.
[22:35] <Laurenceb> hehe
[22:35] Action: Laurenceb has been laying slabs
[22:36] <Laurenceb> used the concrete underneath, brush dry mortar over the top, then spray with water technique
[22:40] <Laurenceb> hopefully I'll have enough time to get the mini rogallo ready for another launch in ~a week
[22:42] <Laurenceb> not sure if its worth replacing ther slightly dodgy polypropylene tube based bearings with sealed bearing units
[22:45] <Laurenceb> or which stands the most chance of jammng at -30C
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[22:48] <shellevil> bearings where?
[22:49] <Laurenceb> fixing the wings onto the vertical spars
[22:49] <Laurenceb> that attatch the tronics enclosure
[22:50] <Laurenceb> for COG shifting
[22:51] <shellevil> ah
[22:52] <Laurenceb> bbl munchies
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[23:25] <Laurenceb> back
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[00:00] --- Mon Apr 27 2009