highaltitude.log.20091109

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[09:50] <MikeMc> Morning
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[10:07] <rjharrison_> Hi
[10:08] <rjharrison_> got home eventually
[10:08] <rjharrison_> http://www.robertharrison.org/listen/altitude.png
[10:08] <rjharrison_> http://www.robertharrison.org/listen/time.png
[10:08] <rjharrison_> some graphs from the launch
[10:14] <Jon_Apex> nice :)
[10:15] <rjharrison_> http://www.robertharrison.org/images/icarus2/Launch5/tree.JPG
[10:15] <rjharrison_> The landin spot
[10:15] <rjharrison_> Can you see the payload
[10:15] <Jon_Apex> yep :)
[10:15] <rjharrison_> The box next to the tunk
[10:15] <rjharrison_> trunk
[10:16] <Jon_Apex> got it
[10:16] <Jon_Apex> glad you got it back :)
[10:18] <Jon_Apex> any details on the payload?
[10:32] <rjharrison_> aLL FINE LOADS OF PICS FOR THE sun newspaper
[10:32] <rjharrison_> Due out next week on the 17th of November
[10:32] <Jon_Apex> good stuff
[10:33] <Jon_Apex> better dash, catch you later
[10:33] <rjharrison_> If there isn't any major news it should be the front page
[10:33] <rjharrison_> ok
[10:33] <rjharrison_> ttfn
[10:47] <juxta> hey rjharrison, how'd you manage to get that down from the tree? haha
[10:49] <juxta> nice data too, interesting that your temperature fell once the payload started falling - due to the improved heat transfer with the moving air as you fell?
[11:11] <SpeedEvil> The temperature at medium levels is lower too
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[13:23] <rjharrison_> Back
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[13:23] <Laurenceb> hi
[13:23] <rjharrison_> juxta bit tricky getting it out of the tree involved a bit of a climb and a very long pole
[13:23] <Laurenceb> wat happened with the saturday flight?
[13:23] <rjharrison_> In short up and down
[13:24] <rjharrison_> success but tricky recovery
[13:24] <rjharrison_> Nice balloon on balloon pics at launch
[13:24] <Laurenceb> balloon on balloon action?
[13:25] <Laurenceb> www.balloonsgonewild.com ?
[13:25] <rjharrison_> lol
[13:25] <rjharrison_> yep
[13:26] <rjharrison_> As the pics have the sun frontpage on i can't post till the 17th of November
[13:26] <Laurenceb> who else was launching>
[13:26] <rjharrison_> But I will post it all
[13:26] <rjharrison_> Steve didsomething for the BBC
[13:26] <rjharrison_> I will be doing a test launch soon if you want a ride
[13:27] <rjharrison_> Will try to give some notice
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[13:27] <Laurenceb> thatnks
[13:28] <Laurenceb> bleh spelling
[13:28] <Laurenceb> yeah I was at SEDS instead - would have come along if I could have
[13:28] <rjharrison_> np
[13:28] <rjharrison_> If you can get across to the M1 I'll give you a lift down at the next launch
[13:29] <Laurenceb> thanks
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[14:14] Action: jcoxon is making ballast tank floats
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[15:02] <Laurenceb> jcoxon: you have the magnetic level thingies?
[15:17] <jcoxon> yes
[15:18] <jcoxon> Laurenceb, am doing a soak test of polystyrene in surgical spirit
[15:18] <jcoxon> see if its a suitable float material
[15:21] <SpeedEvil> I think it will slowly saturate
[15:22] Action: rjharrison_ thinks jcoxon has access to lots of surgical spirit in his like of work ...
[15:22] <rjharrison_> line
[15:24] <jcoxon> SpeedEvil, i'm finding it hard to find materials that float and don't get too upset with ethanol/methanol
[15:25] <SpeedEvil> jcoxon: epoxy coated polystyrene?
[15:26] <SpeedEvil> I think PUR foam - kingspan - would be OK
[15:26] <SpeedEvil> Due to its closed cell strucutre
[15:26] <SpeedEvil> but am unsure
[15:26] <Laurenceb> hmm wood?
[15:26] <SpeedEvil> not many woods will float on alcohol
[15:26] Action: Laurenceb prefers xtratherm
[15:26] <SpeedEvil> balsa probably
[15:26] <Laurenceb> - cheaper than kingspan
[15:27] <Laurenceb> I'm sure you could use a section of small plastic bottle maybe
[15:27] <SpeedEvil> xtratherm = same stuff, different vendor, or expanded polystyrene?
[15:27] <Laurenceb> same stuff different vendor
[15:27] <SpeedEvil> Or a teeny little polybag sealed
[15:27] <Laurenceb> cheap kingspan
[15:27] <SpeedEvil> with air inside
[15:27] <SpeedEvil> oh
[15:27] <SpeedEvil> :)
[15:27] <SpeedEvil> Maybe not.
[15:27] <jcoxon> found that balsa over time soaks up water
[15:27] <SpeedEvil> yeah - varnish
[15:27] <Laurenceb> http://www.xtratherm.com/products/products.php
[15:28] <SpeedEvil> well - polyurethane varnish
[15:28] <SpeedEvil> not the other sort
[15:28] <jcoxon> the float needs to also support a magnet
[15:29] <Laurenceb> does it need to be held close to the side?
[15:29] <jcoxon> relatively
[15:29] <Laurenceb> i.e. if its has a much smaller diameter than the container may to move away from the sening strip?
[15:30] <jcoxon> Laurenceb, yes i'm having that issue, if you shake the container loads and it loses contact for too long the sensing strips internal magnet will drop down
[15:30] <Laurenceb> hmm ideally you want to be able to use a 3L coke bottle without cutting the top right off to get the float in
[15:30] <Laurenceb> this was one of the origional reasons I tried capacitive sensing
[15:30] <Laurenceb> :-S
[15:31] <jcoxon> :-)
[15:31] <jcoxon> for the ballast halo 3 flight i'll only be using a 500ml tank
[15:31] <Laurenceb> maybe a guide rod inside the tank
[15:31] <jcoxon> i've got a cycle water bottle from tescos which has a nice large opening
[15:31] <Laurenceb> brass tube with a float sliding along it
[15:31] <Laurenceb> I see
[15:32] <jcoxon> which might work better as you can get a larger float in
[15:33] <jcoxon> but its certainly not easy
[15:33] <jcoxon> perhaps i should rig you capactive sensor instead
[15:33] Action: Laurenceb has decided that everyone at reaction engines is nuts
[15:34] <jcoxon> how was SEDS
[15:34] <jcoxon> ?
[15:34] <Laurenceb> ivery interesting
[15:34] <Laurenceb> they were rather mad at edmoore
[15:34] <Laurenceb> apparently he didnt return emails
[15:35] <Laurenceb> I dont know what happened there, but the event was very good
[15:35] <jcoxon> hmmmm that doesn't sound like edmoore
[15:35] <jcoxon> perhaps wrong email address
[15:35] <Laurenceb> I know the guy who was organising it from SSTL
[15:35] <Laurenceb> he probably screwed up :P
[15:36] <jcoxon> so whats the next big thing then?
[15:36] <jcoxon> an actual UK space programme?
[15:36] <Laurenceb> heh thats what virgin galactic were talking about
[15:37] <Laurenceb> spaceports in cornwall and scotland
[15:37] <Laurenceb> they look serious about their white night sat launcher
[15:38] <Laurenceb> but they want to develop it in the UK
[15:38] <russss> surely it'll cost loads more to launch from the UK due to the latitude
[15:38] <Laurenceb> its going to be a two stage rocket, maybe with a reusable first stage
[15:38] <Laurenceb> not for polar orbit
[15:38] <russss> ah, true
[15:40] <Laurenceb> they think its better than Plestek
[15:40] <Laurenceb> as north of scotland theres only ocean
[15:40] <SpeedEvil> And finland
[15:41] <Laurenceb> but apparently they are "looking for UK companies to develop the rocket"
[15:41] <Laurenceb> good luck :-/
[15:41] <Laurenceb> I think SSTL pretty much pulled out
[15:41] <Laurenceb> but they might make satellite integrated guidance and control
[15:41] <SpeedEvil> IIRC I came up with the southwest tip ish of scotland
[15:42] <SpeedEvil> northwest
[15:42] <Laurenceb> also SSTL would be their main customer
[15:42] <SpeedEvil> and launch southwest, as south as you can to avoid ireland
[15:42] <Laurenceb> they wanted to launch over the bay of biscay
[15:43] <Laurenceb> with white knight taking off from cornwall
[15:43] <Laurenceb> also they had a video of spaceship2
[15:44] <Laurenceb> its pretty much finished, they are just putting on gelcoat or whatever its finished in
[15:44] <Laurenceb> roll out is scheduled for 3 weeks time
[15:45] <Laurenceb> it was pretty interesting to watch the assembly, its made of about 6 large CF sections glued together
[15:45] <russss> all carbon fibre?
[15:46] <Laurenceb> yes
[15:46] <russss> nice
[15:46] <Laurenceb> Reaction Engines skylon is almost completely composites
[15:47] <Laurenceb> just hasnt been built yet
[15:47] <SpeedEvil> I take it the skylon is not the skylon of yore?
[15:47] <russss> wonder how much it weighs
[15:47] <Laurenceb> http://www.reactionengines.co.uk/skylon_overview.html
[15:47] <Laurenceb> 53 tonnes
[15:47] <edmoore> I never got any emails, jcoxon and Laurenceb
[15:48] <edmoore> I think he was probably mad at Iain
[15:48] <edmoore> he sent iain a message saying 'I enjoyed your talk at AMSAT' even though Iain wasn't at amsat
[15:48] <Laurenceb> they had a dodgy habit of saying "oh that's confidetial intellectual property" or similar whenever there was any tricky question about skylon
[15:49] <Laurenceb> heh yeah he seemed to be being pretty arrogant
[15:51] <Laurenceb> no answers on how they stop the engines frosting or now they attach the silica/silicon carbide outer shell to the CF without it melting
[15:53] <Laurenceb> I stuck some numbers in to guesstimate if the dry mass was sensible and it probably is, but its pretty close to the limit
[15:54] <Laurenceb> apparently its designed to be more like a sandwich structure than as CF structure with al alloy tanks on the siside and silicon carbide composite on the outside
[15:57] <Laurenceb> the CF structure and heat shield are made in small "mass produced" sections then the CF is glued together and the heat sheild panels attach with some sort of slips
[15:57] <Laurenceb> *clips
[15:59] <Laurenceb> http://en.wikipedia.org/wiki/Poly(methylsilyne) <- I presume the heat sheld is made in an argon filled autoclave
[16:01] <SpeedEvil> Interesting
[16:01] <SpeedEvil> And 450C is almost room temperature
[16:04] <Laurenceb> http://www.reactionengines.co.uk/sabre.html
[16:04] <SpeedEvil> I'm unsure of the virtues of single stage.
[16:05] <Laurenceb> Iyeah
[16:05] <SpeedEvil> I mean - sure - it's clearly what you want if you're doing a thousand launches a day.
[16:05] <Laurenceb> they were maing a big point of the fact you can launch 30 tonnes with a space tug
[16:05] <Laurenceb> so that is effectively two stage
[16:06] <Laurenceb> the spaceplane goes suborbital and meets the tug thats "deorbited" itself
[16:07] <Laurenceb> transfers the payload then the tug takes it to orbit where it meets another tanker spaceplane for refuelling
[16:07] <SpeedEvil> much of the complexity of staging, with the added fun of rendevous and tanking.
[16:07] <SpeedEvil> in 0G
[16:08] <Laurenceb> also they have a design for a huge modular spacetug for mars missions ect
[16:08] <Laurenceb> and a "space hanger" and other stuff which is where they start to appear slightly insane
[16:09] <Laurenceb> on and they have a document on how to park skylon vehicles in a hanger
[16:09] <SpeedEvil> yeah - lots of this is stuff that makes sense at >>1000/year
[16:09] <SpeedEvil> But - who the hell would pay for that in this market
[16:09] <Laurenceb> and have designed their own data socket for payloads and interface bus of spaceplane systems
[16:09] <Laurenceb> slightly the wrong focus maybe
[16:10] <Laurenceb> *for
[16:10] <SpeedEvil> You've got - best case - assuming it ticks all the boxes - a launcher that works, and an infrastructure nobody will need for over a decade
[16:10] <SpeedEvil> Even assuming low launch costs of 1K/Kg - who is going to want a thousand launches a year
[16:10] <Laurenceb> space solar power I guess
[16:11] <Laurenceb> maybe helium3 mining
[16:11] <russss> depends when they actually get it working :P
[16:11] <jcoxon> hey Laurenceb
[16:11] <jcoxon> just got out your sensor you made - its quite long...
[16:12] <Laurenceb> heh
[16:12] <SpeedEvil> The other major game-changer would be someone working out how to make ton lots of 30GPa nanotube fibre.
[16:12] <SpeedEvil> Even _very_ expensively.
[16:12] <jcoxon> too long for all the tanks i've got lined up to use
[16:12] <Laurenceb> jcoxon: http://anacarlo.files.wordpress.com/2008/04/father-ted-careful-now.jpg
[16:12] <SpeedEvil> A ten ton tether can get you a 5 ton payload
[16:12] <jcoxon> hehe, i am!
[16:13] <Laurenceb> SpeedEvil: I'm not convinced of ssto spaceplane over a LOX/Kero dropped from a high altitude carrier aircraft
[16:14] <SpeedEvil> yeah
[16:14] <SpeedEvil> though carrier of course sharply limits you in many ways
[16:14] <Laurenceb> all that engine work gets you 1.5Km/sec at 28Km altitude
[16:14] <SpeedEvil> yeah
[16:15] <Laurenceb> beyond that point its just a rocket
[16:15] <SpeedEvil> mach 5.5 isn't really hugely fast
[16:15] <Laurenceb> exactly
[16:15] <SpeedEvil> and means you need more TPS
[16:15] <Laurenceb> the main advantage is higher ISP and less drag when you go to rocket mode
[16:17] <Laurenceb> also as it has wings and a low wing loading unladen re-entry is very gentle
[16:18] <Laurenceb> it take almost 90minutes
[16:19] <SpeedEvil> and wings mean that you've got lots of crossrange of course
[16:19] <Laurenceb> yes
[16:19] <Laurenceb> more importantly they dont get as hot
[16:19] <SpeedEvil> globally no, locally maybe
[16:20] <Laurenceb> so they can use the groovy silicon carbide/silica fabric composite then aluminised kapton foil behind
[16:20] <Laurenceb> the thing I dont understand is how the clips work wout melting holes in the CF structure underneath, but they wouldnt talk about that one
[16:20] <jcoxon> Laurenceb, as the sensor is too long - is it worth me making my own with a second ad7746?
[16:20] <Laurenceb> if you have one you for it
[16:21] <Laurenceb> but I'd change the design a bit
[16:21] <jcoxon> what would you change?
[16:21] <Laurenceb> the tube is a bit small
[16:21] <Laurenceb> you get a meniscus forming that screws the readings
[16:22] <jcoxon> what sort of size would you go to?
[16:22] <Laurenceb> also it was hard to seal the electrodes against galvanic effects
[16:22] <Laurenceb> maybe 6mm ID or larger
[16:22] <jcoxon> i can get hold of the sparkfun ad7746 board very easily
[16:23] <jcoxon> iirc hackspace have a load in the spares box
[16:23] <Laurenceb> I know
[16:23] <Laurenceb> use some brass tube as small as you can get for the electrodes
[16:23] <Laurenceb> then conver with heat shrink
[16:24] <Laurenceb> one continuous lenght of heat shrink
[16:24] <jcoxon> so its 2 brass tubes covered in heatshrink within a copper pipe
[16:24] <Laurenceb> so if you want a 10cm sensor, get about 22cm or heatshrink
[16:24] <jcoxon> the heatshrink seperating them from each other
[16:24] <Laurenceb> then a tube in each end and heat it
[16:24] <Laurenceb> then fold it
[16:24] <Laurenceb> and stick inside the outer tube
[16:24] <jcoxon> i see
[16:24] <Laurenceb> maybe not copper tube, its heavy
[16:25] <Laurenceb> you can get thinwall brass tube
[16:25] <jcoxon> does it need to be metal?
[16:25] <Laurenceb> you might have to resort to buying online, not sure
[16:25] <Laurenceb> yes
[16:25] <Laurenceb> its for EMI protection
[16:25] <jcoxon> right
[16:25] <Laurenceb> a good engineering supplier would help
[16:26] <Laurenceb> trying hobby shop type places is always annoying
[16:26] <jcoxon> the two tubes are then attached to channel one and two of the sensor
[16:26] <Laurenceb> but then engieering suppliers would make you buy a lot
[16:26] <Laurenceb> erm I dont think so
[16:26] <Laurenceb> theres two channels, each one has two outputs
[16:26] <jcoxon> oh right
[16:27] <jcoxon> so you use just one channel
[16:27] <Laurenceb> so one to the "exciter" and one to the "receiver"
[16:27] <Laurenceb> or whatever they are called in the datasheet
[16:28] <Laurenceb> I found that meniscus and galvanic effects made my results screwy
[16:28] <jcoxon> urgh this damn ballast sensor
[16:29] <jcoxon> Laurenceb, oh and i need to kick you about starting work on the flight computer :-p
[16:29] <jcoxon> well the flight firmware rather
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[16:50] <Laurenceb> ok
[16:50] <Laurenceb> afk
[16:50] <Randomskk> man, choosing a radio is tricky business
[16:54] <edmoore> Randomskk: 817
[16:54] <edmoore> it's a joy
[16:54] <Randomskk> it is half the price of something twice as good, but the issue is if I want something twice as good later then I'd have been better off buying that to start with?
[16:56] <Randomskk> edmoore: btw 400W of peltier coolers and a 600W power supply that'l do 36A at 12V ordered for this ice-making project :D
[16:58] <SpeedEvil> where peltiers?
[16:59] <russss> oh cock, you could have borrowed my peltiers :P
[16:59] <russss> they are sitting round doing nothing
[16:59] <Randomskk> the peltiers were cheap from hong kong
[16:59] <russss> so were mine ;)
[16:59] <Randomskk> though how good they are I will have to wait and see
[16:59] <Randomskk> they say 100W 12V
[16:59] <Randomskk> and 4cm*4cm
[17:00] <russss> I believe mine are 400W @ 12V, same size
[17:00] <Randomskk> whether they can really take actual 100W 12V I will find out soonish. also how efficient they are.
[17:00] <SpeedEvil> Generally.
[17:00] <Randomskk> the enthalpy of fusion for the water is the high-energy part.
[17:00] <SpeedEvil> Peltiers are a maximum of 50% efficient at half their nominal temperature range.
[17:00] <SpeedEvil> max
[17:00] <Randomskk> the specific heat capacity energy is minimal, to get from fridge-cold to 0C
[17:00] <SpeedEvil> and half their current
[17:01] <Randomskk> SpeedEvil: does increasing current increase or decrease efficiency?
[17:01] <SpeedEvil> So going from 20C to -10C - you can expect 50W of cooling at 50W input power
[17:01] <SpeedEvil> and at 100W power - 0W of cooling power at 60C differential
[17:01] <Randomskk> 50W cooling at 50W input?
[17:02] <SpeedEvil> yes - ish
[17:02] <Randomskk> isn't that 100% efficiency?
[17:02] <SpeedEvil> not really.
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[17:03] <SpeedEvil> An optimal carnot engine going from 20C to -10C using 1W of power will pump around 25W of heat.
[17:03] <SpeedEvil> A peltier about 1, and a 'normal' refrigerator maybe 4-7
[17:03] <russss> I was going to try stacking them to liquify air, but then I did the math.
[17:03] <Randomskk> oh, right, fair enough
[17:04] <SpeedEvil> Coefficient of performance
[17:04] <SpeedEvil> As you go much from 50% of maximum sticker power - the losses mount hugely - and the COP drops well below 1
[17:05] <SpeedEvil> As at high temperature differentials, all of the useful heat pumping capability goes into parasitic heat losses through the device.
[17:05] <russss> peltiers also only work at peak efficiency at a certain temperature differential
[17:06] <SpeedEvil> About half the maximum differential is probably ballpark, and about half the 'sticker' power for optimal performance COP wise.
[17:06] <russss> the optimal differential on mine is something like 55 degrees
[17:06] <SpeedEvil> You can increase the power and get more absolute cooling, but not good watt for watt
[17:06] <Randomskk> right, I see.
[17:06] <russss> yeah, and then you've got to get rid of the heat on the other side
[17:07] <SpeedEvil> Ideally there should be curves on the datasheet that you can extrapolate from, and work out the performance
[17:07] <Randomskk> in this instance the electricity is paid for by the uni, and we're only planning on using it occasionally, so amount of energy consumed is less of an issue than the time taken to freeze the water
[17:07] <Randomskk> russss: got a massive metal kitchen surface that's flat and then bumpy and also a sink which should heatsink pretty nicely
[17:07] <SpeedEvil> Get a good CPU fan, or similar.
[17:08] <SpeedEvil> And put a larger fan on it. Ideally solder the peltier onto it, though that can be tricky
[17:08] <russss> Randomskk: I actually have an old CPU watercooling heatsink
[17:08] <SpeedEvil> (indium will probably wet it)
[17:08] <Randomskk> we were thinking of using a heatsink and putting it in the fridge, but it seems like the metal surface of the kitchen top should heatsink pretty well
[17:08] <SpeedEvil> If clamping, look at typical clamping forces - IIRC 1Kg/cm^2 is common
[17:09] <SpeedEvil> It's probably stainless steel.
[17:09] <SpeedEvil> Stainless steel is a _lousy_ conductor.
[17:09] <russss> but stacking them to liquify air is a bit ambitious I think.
[17:09] <Randomskk> bugger. it probably is, at that.
[17:09] <Randomskk> hmm
[17:10] <Randomskk> well atm I've got the peltiers and psu ordered, we are gonna try and pick up some offcuts from engineering to get the sheet metal and piping
[17:10] <Randomskk> (where the piping is on top of the sheet metal to hold the water)
[17:10] <Randomskk> thinking of insulating the metal on the top with some foam too
[17:11] <Randomskk> will see how well it works out and if needed a big heatsink is certainly possible
[17:11] <Randomskk> or watercooling using the sink's tap
[17:11] <SpeedEvil> How much water are you trying to freeze?
[17:11] <Randomskk> a couple of ice cube's worth
[17:12] <Randomskk> about 0.02kg?
[17:12] <SpeedEvil> For a small amount, 3l of water, pumped through a watercooled heatsink will be just fine.
[17:12] <SpeedEvil> Also illuminates the heat loss on the other side
[17:12] <SpeedEvil> heat gain
[17:12] <Randomskk> so you don't reckon the kitchen top will be conductive enough to get heat away fast enough?
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[17:15] <Randomskk> wb
[17:18] Action: Laurenceb broke his mouse :-/
[17:18] <Laurenceb> no scroll wheel
[17:18] <rjharrison_> sbasuita how is the payload going?
[17:18] <Laurenceb> I just dismantled it, theres a nice quadrature encoder switch on the scroll wheel, maybe useful for something
[17:18] <Laurenceb> well its smashed now - thats why it was broken :-/
[17:22] <sbasuita> rjharrison_, we're waiting on a new camera
[17:22] <rjharrison_> OOh
[17:22] <rjharrison_> The 560?
[17:23] <sbasuita> rjharrison_, I'm not sure - alex has ordered it off ebay
[17:23] <rjharrison_> I got the one I ordered the other day
[17:23] <sbasuita> rjharrison_, it's either the programmable one or an a60/80
[17:23] <rjharrison_> Yep we all ordered the a560 at the same time for 50 pounds
[17:23] <sbasuita> yes it is the a560
[17:23] <rjharrison_> I think MikeMc got one too
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[17:25] <edmoore> Randomskk: sorry got distracted by work
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[17:25] <edmoore> erm, i think the 817 has advantages in and of itself, it's not just an (ic-7000)/2
[17:26] <Randomskk> if only comparison shopping was that easy
[17:26] <edmoore> that said, for general TX work, having 100W on HF is a nice thing
[17:26] <Laurenceb> http://www.youtube.com/watch?v=T67AewxhBaQ
[17:26] <rjharrison_> 817 is portable which is good and can be run off a small battery
[17:27] <rjharrison_> the ic-7000 is a gread base station but you need a hefty power supply to go portable
[17:28] <edmoore> agreed, with both just idling, the ic-7000 pulls more current
[17:29] <Randomskk> it also looks way cooler and has a nicer screen?
[17:30] <rjharrison_> Ok the IC-7000 is a very nice looking radio
[17:30] <rjharrison_> oh
[17:30] <DanielRichman> And is twice the price of a 817
[17:30] <edmoore> well, i guess. it's sort of apple and oranges
[17:30] <Randomskk> not as cool or as nice a screen as the 7800 but that's kinda pricy and big
[17:30] <Randomskk> and a tad pointless :P
[17:31] <edmoore> 817 tells you the freq and s-meter, 7000 will do waterfull plots, SWR graphs, RTTY decoding, and all sorts
[17:31] <Randomskk> which is all pretty cool though I guess my laptop can do that too, when connected up?
[17:31] <rjharrison_> the 7000 has it all
[17:31] <rjharrison_> but portability is the issue
[17:31] Action: Randomskk can't even use 100W yet, admittedly, but hopefully soon
[17:32] <rjharrison_> Randomskk have a look at edmoore's
[17:32] <Randomskk> guess so. it didn't seem too much bigger or heavier in and of itself, but I guess the power supply is a significant issue
[17:32] <edmoore> have only used the full power of the 7000 in anger when doing balloon uplinks
[17:32] <Randomskk> I did have a glance at both of them on saturday
[17:32] <rjharrison_> actress bishop etc...
[17:32] <rjharrison_> lol
[17:32] <rjharrison_> that full power would be useful for ulinks
[17:33] <rjharrison_> getting blasted with 30-40w uhf should do the trick line of sight
[17:33] <Randomskk> hm, also this place does the 817 or the 817+ bhiDSP ND
[17:33] <rjharrison_> who has the 817 @ cusf?
[17:34] <edmoore> bought one for CUSF
[17:34] <edmoore> it's club-owned
[17:34] <rjharrison_> Not sure you need the extra DSP
[17:34] <rjharrison_> edmoore cool
[17:34] <rjharrison_> So that's the portable option then
[17:34] <Randomskk> I wish ofcom would hurry up and let me pick a callsign :P
[17:34] <edmoore> well, it's a 2nd radio
[17:34] <edmoore> used it to track XABEN at the weekend
[17:34] <rjharrison_> Yep usefull
[17:34] <edmoore> the 790 becomes the 3rd radio
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[17:35] <rjharrison_> I have found lots of uses for my secondone
[17:35] <edmoore> can't believe steve got a 290 on freecycle
[17:35] <rjharrison_> yep that was amazing
[17:35] <rjharrison_> will have to watch the local free cycle
[17:35] <edmoore> i am watching mine like a hawk :)
[17:36] <edmoore> oh god my stomach
[17:36] <edmoore> have been pcb designing all day and just forgot all about lunch
[17:36] <Laurenceb> heh
[17:36] <Laurenceb> what are you working on?
[17:37] <Randomskk> lol I hate it when that happens
[17:37] <edmoore> hobble avionics
[17:37] <Randomskk> edmoore: is hobble your 4th year project?
[17:37] <edmoore> there's quite a lot and I really want it to work without bodges
[17:37] <edmoore> yep
[17:37] <Laurenceb> cool, ARM based?
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[17:38] <edmoore> lots of things hanging off a uart with avrs
[17:38] <edmoore> not actually sure about what the master will be yet
[17:38] <rjharrison_> Right im off to set up my talk
[17:38] <edmoore> could be badger2
[17:38] <MikeMc> Yes I ordered an A560 too
[17:38] <rjharrison_> Starts at 7
[17:38] <edmoore> but badger2 pulls so much current
[17:38] <Laurenceb> UART?
[17:38] <edmoore> yep
[17:38] <Laurenceb> wouldnt I2C or SPI be better?
[17:38] <edmoore> one big system-wide serial
[17:38] <edmoore> no
[17:39] <edmoore> why would it be better?
[17:39] <Laurenceb> fairdoos
[17:39] <edmoore> i've got ~1m runs of cabling to do
[17:39] <Laurenceb> device addressing in hardware and or faster
[17:39] <Laurenceb> I see
[17:39] <edmoore> the entire system has a bandwidth of only about 100hz
[17:39] <Laurenceb> using rc servos?
[17:39] <Laurenceb> what scope are you using?
[17:39] <edmoore> 115kbps will easily hangle that
[17:39] <edmoore> am using them for fine adjustment
[17:39] <edmoore> a camera
[17:40] <Laurenceb> oh ok thats simple
[17:40] Action: Laurenceb was picturing a large reflector
[17:40] <edmoore> am picking my battles
[17:40] <Laurenceb> yeah good move
[17:40] <rjharrison_> http://www.ntileeds.co.uk/old-broadcasting-house/
[17:40] <Laurenceb> well large as in 15cm or so
[17:40] <rjharrison_> This where I'm doing the talk tonigh
[17:40] <rjharrison_> t
[17:41] <edmoore> very nice!
[17:41] <rjharrison_> Chat later when I get there
[17:41] <edmoore> what time is the talk?
[17:41] <rjharrison_> 15 mins
[17:41] <rjharrison_> 7pm
[17:41] <edmoore> i could bomb up the A1
[17:41] <edmoore> caution to the wind
[17:41] <rjharrison_> lol
[17:41] <edmoore> ah, wouldn't make it
[17:45] <rjharrison_> The talk is loosly based around this set of slides http://www.robertharrison.org/svn/filedetails.php?repname=the-icarus-project&path=%2Ftalks%2F2009-11-09+wylug%2FThe+Icarus+Project.pdf
[17:46] <russss> is this related to the leeds hackspace?
[17:48] <rjharrison_> Yep I did a talk there last hackday
[17:49] <rjharrison_> and a talk tonight at OBH
[17:49] <russss> ah cool
[17:49] <rjharrison_> russss you comming?
[17:49] <Randomskk> we need a cambridge hackspace :(
[17:50] <edmoore> There's very loud rumbles about it.
[17:51] <rjharrison_> Leeds is waiting for Cambridge to catch up :)
[17:51] <edmoore> Have had convos are the last 6 months with several people/groups who have been talking about it seriously, but I've no idea whether or not they're talking to each other and what stage of completion they're at
[17:51] <Randomskk> the guy from the MIT startup I've been working with is also keen to get something going and has also apparently been talking to people
[17:51] <rjharrison_> laters all
[17:51] <russss> well ask them to get in touch with me
[17:52] <russss> I can probably sort out beer if not money.
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[17:52] <Randomskk> he's of the opinion that the cambridge students don't have enough time after course work to do more engineering in their off time
[17:52] <edmoore> russss: have any guys from Redgate software been in contact?
[17:52] <Randomskk> or at least, that a significant fraction don't, and that of them, many would rather just relax and do nothing related to engineering
[17:52] <Randomskk> which seems kinda a massive shame
[17:53] <russss> edmoore: Not with me, but maybe jontyw
[17:53] Action: Randomskk would have to disagree as he is working on a peltier ice maker, quadcopter, this microphone thing, plus all the cusf stuff
[17:53] <russss> we need some kind of CRM system to deal with all the people contacting us ;)
[17:53] <edmoore> rjharrison: the slides look great
[17:53] <edmoore> am annoyed I can't come
[17:53] <Randomskk> anyway bbl dinner, then see you at the meeting edmoore
[17:54] <edmoore> oh god
[17:54] <edmoore> so there is
[17:54] <edmoore> not sure I can face that
[17:54] <Randomskk> lol
[17:54] <Randomskk> after working on pcbs all day long? :P
[17:54] <edmoore> am never going to get any work done at this rate. right, had better eat now then
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[19:01] <sbasuita> http://news.bbc.co.uk/1/hi/technology/8349923.stm
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[20:24] <SPUDNIK1> Hello, anybody there?
[20:24] <SPUDNIK1> ?
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[20:25] <SPUDNIK1> hello
[20:25] <jcoxon> hi SPUDNIK1
[20:25] <SPUDNIK1> hi
[20:25] <jcoxon> hey Laurenceb, managed to make a new ballast sensor
[20:25] <Laurenceb> oh wow ok
[20:25] <SPUDNIK1> hows it going?
[20:25] <Laurenceb> how?
[20:25] <SPUDNIK1> cool
[20:26] <Laurenceb> hello SPUDNIK1
[20:26] <jcoxon> Laurenceb, it may sound crazy - blue LED at base, and then photocell at the top
[20:26] <SPUDNIK1> i have a question...!
[20:26] <Laurenceb> ermm...
[20:26] <jcoxon> then cover the tank so its dark
[20:26] Action: Laurenceb is confused
[20:26] <Laurenceb> how does that work? add die?
[20:26] <jcoxon> that i'm not sure about
[20:27] <jcoxon> but i get about 200 difference between full and empty
[20:27] <jcoxon> relatively accurately
[20:27] <jcoxon> SPUDNIK1, whats your question?
[20:27] <Laurenceb> using alcohol?
[20:27] <sbasuita> jcoxon, is the relation between volume and brightness linear?
[20:27] <jcoxon> water right now - don't have enough alcohol to fill the tank
[20:27] <jcoxon> sbasuita, i'm still working on that
[20:29] <Laurenceb> not a big issue, do you have scales?
[20:29] <jcoxon> only bathroom scales
[20:29] <jcoxon> going to make a second prototype - slightly cleaner this time
[20:30] <Laurenceb> hmm try a tube
[20:30] <Laurenceb> with the led at the bottom in some expoy
[20:30] <Laurenceb> also you could pulse the led on/off and record the difference to help remove th effect of any leaking ambient light
[20:31] <jcoxon> okay will set this up
[20:32] <Laurenceb> make sure its not electrolysing the water
[20:33] <sbasuita> Laurenceb, pulsing is a really good idea
[20:33] <jcoxon> i actually had the photo sensor outside the tank
[20:33] <jcoxon> through the plastic
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[20:33] <jcoxon> but this time i'm going to use a black cycle water bottle
[20:34] <jcoxon> so they'll be minimal ambient light
[20:34] <jcoxon> right this'll take a bit of time...
[20:34] <Laurenceb> will you maunt the led inside?
[20:34] <Laurenceb> this is a really clever idea :D
[20:34] <jcoxon> what i did last time was drill a hole and then wedge the led in and glue it
[20:35] <Laurenceb> the only thing I can think of is photoresistors are very sensitive to temperature
[20:35] <Laurenceb> hmm the glue may crack at low temperature
[20:35] <jcoxon> oh Laurenceb this is for testing right now!
[20:35] <Laurenceb> for the flight maybe a photodiode
[20:35] <jcoxon> we could temp compensate
[20:36] <jcoxon> but its the ease of use thats the key
[20:36] <jcoxon> nothing floating, nothing in the tank itself :-p
[20:37] <Laurenceb> yeah
[20:37] <Laurenceb> well
[20:37] <Laurenceb> I'd but no holes in the bottom over noting in the tank
[20:37] <Laurenceb> *put
[20:38] <jcoxon> well we could always not have holes, use a transparent tank add the led and photocell and then cover it to block out ambient light
[20:38] <jcoxon> then all you'd have going in was the outlet and perhaps an air entry
[20:38] <Laurenceb> yeah have them sealed inside a tube
[20:38] <Laurenceb> oh I know
[20:38] <jcoxon> :-p
[20:38] <Laurenceb> you have a pipe out the bottom anyway
[20:39] <jcoxon> first step - test rig to test theory...
[20:39] <Laurenceb> so you can stick a level sensor onto that
[20:39] <Laurenceb> completely external to the tank
[20:39] <jcoxon> Laurenceb, do you think the blue led was important or will any led do?
[20:39] <Laurenceb> just a vertical lenght of pipe with an led at one end and diode at top
[20:39] <Laurenceb> blue probably helps a bit
[20:39] <Laurenceb> actually no
[20:39] <Laurenceb> hmm
[20:40] <Laurenceb> yeah I'm not sure it depends whats absorbed by alcohol
[20:40] <Laurenceb> or just add die
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[20:44] <jcoxon> hmmm i'm not going to be able to extract this blue led
[20:44] <jcoxon> gonna have to be another one
[20:45] <jcoxon> we;ll go with red
[20:46] <Laurenceb> can always add die
[20:46] <Laurenceb> erm dye
[20:47] <Laurenceb> hah cool http://news.slashdot.org/comments.pl?sid=1436510
[20:52] <jcoxon> for now will a ldr get upset it gets a bit of water on its top (not the wire bit)
[20:52] <Laurenceb> no
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[20:58] <SPUDNIK16> Hi Everyone
[20:58] <jcoxon> hi SPUDNIK1
[20:58] <SPUDNIK16> I'm new to this so please try and put up with my very basic questions
[20:58] <SPUDNIK16> hi jcoxon
[20:58] <SPUDNIK16> parachutes....
[20:59] <SPUDNIK16> how do you stop the chute reversing on its way up?...
[20:59] <jcoxon> yup
[20:59] <SPUDNIK16> we thought about running the string through the middle...
[20:59] <SPUDNIK16> but then on its way down the string above attached to the balloon hit the top of the chute and it crashes down.
[21:00] <jcoxon> unfortunately that is one of the risks
[21:00] <SPUDNIK16> we tried hooking the chute to the main string going up to the balloon hoping when it fell it would un-hook (it didn't work reliably)
[21:01] <SPUDNIK16> Oh
[21:01] <jcoxon> often people have cutdowns to sever the line so that nothing comes crashing down
[21:01] <SPUDNIK16> but surely the string will fall faster than the chute, in which case it will drag the chute down from the top.
[21:02] <SPUDNIK16> ah. - that would work, but its hard to do
[21:02] <jcoxon> not if its severed near to the parachute
[21:02] <jcoxon> indeed it is
[21:02] <SPUDNIK16> ok, but if you dont do that...
[21:02] <jcoxon> its seems ot be a good idea to run a long line btween the parachute and the balloon
[21:02] <SPUDNIK16> what else? - the best i could do was hook the chute to the main line
[21:02] <jcoxon> rather then crash down it seems to fall past
[21:03] <SPUDNIK16> that way it won't inverse going upwards but will un-hook falling down
[21:03] <jcoxon> sounds like a good idea
[21:03] <SPUDNIK16> thanks ;)
[21:03] <jcoxon> most of the time people don't do anything - usually the parachute works :-p
[21:03] <SPUDNIK16> it's not 100% reliable
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[21:03] <SPUDNIK16> so most people run the main string through the parachute?
[21:04] <jcoxon> yup
[21:04] <jcoxon> its more reliable to have the parachute pre deployed
[21:04] <SPUDNIK16> yeah
[21:04] <jcoxon> i have a small block on the main line running through the parachute that keeps it in place
[21:04] <jcoxon> the parachute rests on it
[21:05] <SPUDNIK16> and it is impossible to have the parachute attached to the side right? - it will always open on its way up
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[21:05] <jcoxon> when the main line goes slack (balloon bursting) the parachute inflates and rises off the block
[21:05] <SPUDNIK16> yeah - it made a block (invented it in my case)
[21:05] <SPUDNIK16> cool - great minds think alike
[21:05] <jcoxon> :-)
[21:06] <SPUDNIK16> ok so in summary:
[21:06] <SPUDNIK16> 1) the main line has to go through the chute (with the use of a block) to stop it inverting
[21:07] <SPUDNIK16> 2) its just a risk that the slack string drags the parachute down (it is impossible for it to stop it effecting it to a degree)
[21:07] <SPUDNIK16> 3) the hook is better than nothing
[21:07] <SPUDNIK16> ?
[21:07] <jcoxon> yup
[21:07] <jcoxon> nothing is 100% in ballooning
[21:08] <jcoxon> but you need to minimise the risks
[21:08] <jcoxon> other tips - try and make your payload as light as possible, lots of insulation and padding to soften landing
[21:08] <SPUDNIK16> ok
[21:09] <jcoxon> so you've launched already? or planning a launch?
[21:10] <SPUDNIK16> launching wednesday or sat
[21:10] <jcoxon> ooo cool
[21:10] <jcoxon> from where?
[21:10] <SPUDNIK16> we are in south devon, not sure of the weather conditions
[21:10] <jcoxon> oh great - another UK group
[21:11] <jcoxon> how you planning to track your payload?
[21:11] <SPUDNIK16> what do you recon? - we are very new to this. no issues with the gps, cameras, programming (we are techies) but all the elements unique to this project are new to us.
[21:12] <SPUDNIK16> we are using gps, a blackberry and as back-up radio trasnmitter
[21:12] <SPUDNIK16> we can't track it all the way up, just the landing spot
[21:12] <jcoxon> sounds like a good plan
[21:12] <jcoxon> have you seen http://wiki.ukhas.org.uk ?
[21:13] <SPUDNIK16> yeah
[21:13] <jcoxon> cool
[21:13] <jcoxon> well this channel is the place to be regarding uk (and the world) balloon launches
[21:13] <jcoxon> 2 launches last sat
[21:13] <jcoxon> http://spacenear.us/tracker/
[21:13] <jcoxon> ignoring the random point in leeds :-p
[21:13] <SPUDNIK16> www.spudnik1.co.uk - thats us, we are updating the site after launch
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[21:14] <jcoxon> what freq is your radio?
[21:15] <SPUDNIK1> not sure, alex did that
[21:15] <SPUDNIK1> can i call you?
[21:15] <jcoxon> fair enough
[21:16] <SPUDNIK1> we are spending tonight on it and want to get everything sorted. alex is busy programming, i was throwing things out my window
[21:17] <jcoxon> SPUDNIK1, what IRC client are you using - i don't think it does PMs
[21:17] <SPUDNIK1> not sure, i meant are you ok for a 5mins chat?
[21:17] <jcoxon> okay
[21:17] <SPUDNIK1> i'll call your mobile.. it would be a great help
[21:18] <jcoxon> whats your email - i'll email you it
[21:20] <SPUDNIK1> hmmmm...
[21:21] <SPUDNIK1> you can call me if you'd prefer
[21:21] <SPUDNIK1> 07969461168
[21:21] <SPUDNIK1> name's Chester
[21:21] <jcoxon> its just this channel is logged publically
[21:22] <SPUDNIK1> alex asked if you know fergus?
[21:22] <jcoxon> fergus noble?
[21:22] <jcoxon> yup
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[21:22] <SPUDNIK1> lol
[21:22] <SPUDNIK1> yes
[21:22] <jcoxon> and henry?
[21:22] <SPUDNIK1> alex has been chatting with him
[21:22] <jcoxon> oh right
[21:22] <SPUDNIK1> not henry
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[21:31] <Laurenceb> heh prank calls in 3..2..1
[21:32] <Laurenceb> "a unique solution to home veg-box delivery."
[21:32] <Laurenceb> lol
[21:32] <DanielRichman> Have they developed spam bots to harvest phone numbers now too?
[21:35] <jcoxon> SPUDNIK1, http://www.srcf.ucam.org/~cuspaceflight/predict/index.php
[21:36] <Laurenceb> jcoxon: I think with a photodiode your idea is the best yet
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[21:45] <jcoxon> SPUDNIK1, http://www.srcf.ucam.org/~cuspaceflight/predict/index.php
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[21:57] <jcoxon> okay my sensor is saying 275 full
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[22:05] <MikeMc> Evening
[22:05] <Randomskk> yo
[22:09] <edmoore> hi
[22:09] <edmoore> Randomskk: am going to try and get gsource working and may shift hobble over to git
[22:09] <Randomskk> gource
[22:09] <Randomskk> http://code.google.com/p/gource/
[22:09] <Randomskk> cool
[22:09] <edmoore> that would be why i couldn;t find it just now
[22:10] <Randomskk> if you do, github is awesome
[22:12] <edmoore> seems gource is on macports
[22:12] <edmoore> that makes things easy
[22:12] <Randomskk> oh yup
[22:18] <edmoore> it's updating absolutely everything. great
[22:18] <Randomskk> in what sense?
[22:19] <edmoore> updating the ports
[22:19] <edmoore> it's re-compiling octave and so on. quite needlessly
[22:19] <Randomskk> lol great
[22:19] <Randomskk> why someone doesn't port apt to mac I don't get
[22:19] <Randomskk> if you could pick any of the linux package managers to port to os x
[22:20] <Randomskk> why on earth do you pick portage
[22:20] <DanielRichman> portage is quite nice
[22:20] <DanielRichman> well... it's ok
[22:20] <DanielRichman> apt is better though, i'd agree
[22:24] Nick change: SpeedEvil1 -> SpeedEvil
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[22:56] <natrium> yo
[22:56] <natrium> anybody need google wave invites?
[22:57] <Randomskk> I'd love one. how many do you get to give out?
[22:57] <edmoore> wouldn't say no if you've got some going spare
[22:57] <natrium> i got 30 left
[22:57] <natrium> emailz plz
[22:57] <Randomskk> random@randomskk.net <3
[22:57] <MikeMc> :D
[22:58] <natrium> added
[22:58] <SpeedEvil> Do they work in the UK?
[22:58] <natrium> edmoore, ?
[22:58] <natrium> yeah
[22:58] <natrium> it's the internet
[22:58] <natrium> :)
[22:58] <edmoore> pm'd you
[22:58] <MikeMc> mike@earthshinedesign.co.uk pls
[22:58] <Randomskk> I'm tempted to start bringing my laptop with me to places more often
[22:58] <jcoxon> natrium, me please!
[22:58] <natrium> MikeMc, added
[22:58] <edmoore> stuck in tubes :)
[22:58] <jcoxon> right and the empty rate is 435 :-)
[22:59] <SpeedEvil> If possible - natrium@mauve.plus.com, thanks!
[22:59] <MikeMc> ty
[22:59] <Randomskk> f5 f5 f5
[22:59] <edmoore> still building octave
[22:59] <Randomskk> though f5'ing gmail is pretty counterproductive
[22:59] <edmoore> sigh
[22:59] <natrium> jcoxon, sent
[22:59] <natrium> lol SpeedEvil
[22:59] <Randomskk> edmoore: lol
[22:59] <natrium> throw away email :P
[23:00] <natrium> Randomskk, "Invitations will not be sent immediately. We have a lot of stamps to lick. "
[23:00] <SpeedEvil> Anything that might be publically logged gets a random
[23:00] <SpeedEvil> so I can kill it if I start getting spam
[23:00] <edmoore> ah cool
[23:01] Action: SpeedEvil should be able to do stuff soon. Just preparing stuff for the first frosts
[23:01] <Randomskk> natrium: haha
[23:02] <jcoxon> natrium, edmoore, laurence and i might have cracked a ballast tank sensor
[23:02] <edmoore> with force or with ethanoly witchcraft?
[23:03] <jcoxon> hehe, using an led and a photocell
[23:03] <jcoxon> :-p
[23:03] <edmoore> oh!
[23:03] <SpeedEvil> Photocells I'm unsure of their response at low temps
[23:03] <edmoore> cracked in the idiomatic sense
[23:03] <jcoxon> SpeedEvil, probably switch to photodiode
[23:04] <SpeedEvil> you use a dye?
[23:04] <jcoxon> not at present
[23:04] <SpeedEvil> Or is it a TIR level sensor
[23:05] <jcoxon> between empty and full in a 500ml tank 275 - 435
[23:05] <jcoxon> so a fair range
[23:06] <SpeedEvil> how does it work - simply absorbtion by the liquid?
[23:06] <jcoxon> i guess so
[23:06] <jcoxon> but it really does work
[23:06] <naxxfish> phototransistor surely would be less of a pain?
[23:07] <jcoxon> naxxfish, this is a proto prototype so i guess anything that does photo
[23:07] <naxxfish> sorry, randomly butting into a conversation with no context >_<
[23:07] <jcoxon> all input is welcome!
[23:07] <SpeedEvil> mouse sensor - they are a quid, and you get a 16*16 camera
[23:07] <naxxfish> i suppose it depends how you're intending to measure it
[23:07] <SpeedEvil> (but no lens)
[23:09] <jcoxon> well at present this option is a lot better the capacitive sensing and also magentopot
[23:09] <jcoxon> so much more simple - with i think is the best approach
[23:10] <SpeedEvil> I'd go with a phototransistor and LED.
[23:10] <SpeedEvil> unless you can guarantee no stray light - it makes chopping easier
[23:10] <SpeedEvil> flash light at 1KHz
[23:10] <SpeedEvil> output - light output - dark output
[23:10] <naxxfish> you could do two identical LEDs and use one as a photodiode :)
[23:11] <jcoxon> :-)
[23:11] <naxxfish> that way the frequency response will be such that the light from the LED will be better picked up
[23:11] <naxxfish> so stray light is a bit less of an issue
[23:12] <SpeedEvil> naxxfish: AIUI, it doesn't really work that way - but it's been a while since I looked at it.
[23:12] <SpeedEvil> LEDs suck as photoreceptors anyway
[23:12] Action: SpeedEvil pulled the trigger on a 4W laser from ebay.
[23:12] Action: SpeedEvil wants to try laser soldering.
[23:12] <naxxfish> they're not particularly good, no
[23:13] <Randomskk> SpeedEvil: what colour?
[23:13] <SpeedEvil> NaN
[23:13] <edmoore> ah, build finished
[23:13] <naxxfish> IR?
[23:13] <SpeedEvil> 910nm?
[23:13] <SpeedEvil> 915
[23:15] <SpeedEvil> Hmm
[23:15] <SpeedEvil> Why does that number ring a bell.
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[23:25] <SpeedEvil> I think it's a narrow absorbtion band of water in the atmosphere where almost no light gets through
[23:28] <natrium> hehe, laser soldering sounds a bit hard to get right
[23:28] <natrium> you need to worry about reflectance
[23:30] <SpeedEvil> Looks like I was thinking of 935ish
[23:30] <jcoxon> natrium, i didn't get an email :-(
[23:30] <SpeedEvil> Well - worst case it doesn't work, and goes on ebay
[23:30] <natrium> jcoxon, it can take a while
[23:30] <Randomskk> jcoxon: apparnently they "have a lot of stamps to lick" i.e. it takes ages
[23:30] <natrium> the first wave of invites took one week
[23:31] <natrium> but this wave might be quicker
[23:31] <SpeedEvil> I got one. It offered me a african prince who'd died, and left his legacy of a really large penis ready for transplant.
[23:31] <jcoxon> oh right :-)
[23:32] <edmoore> Randomskk: keep an eye out for some old computer hardware + tower
[23:32] <edmoore> freenas + £150 on discs and we'll have ourselves a CUSf fileserver that should last a while
[23:33] <edmoore> as rjharrison pointed out, a balloons flight can nowadays gnerate 15GB of data
[23:33] <Randomskk> will do
[23:33] <Randomskk> actually I have a server at home that I don't use since going to slicehost
[23:34] <Randomskk> it's a few years old but what, 512mb ram and a few gigahertz cpu? might or might not have sata for hard drives, definitely has ide
[23:34] <edmoore> that'd do it
[23:35] <Randomskk> could probably bring that down next term
[23:35] <edmoore> slicehost looks pretty good
[23:35] <natrium> edmoore, is that picture data?
[23:35] <edmoore> mainly
[23:35] <natrium> 15GB sounds a bit high
[23:35] <edmoore> and i guess a lot is garbage
[23:35] <natrium> ah
[23:35] <Randomskk> slicehost's been great for me so far, plus pretty cheap and their support is excellant, their online docs and tutorials are great
[23:36] <Randomskk> I like to compare them to sparkfun in that they have all sorts of tutorials on how to use their products and are pretty open about everything
[23:36] <Randomskk> not ideal for just storing lots of files though
[23:36] <Randomskk> btw talking of which, could probably back up the cusf stuff to amazon s3, it's super easy to do with Duplicity and costs pretty much nothing
[23:36] <Randomskk> I pay like 30¢ a month to amazon for backing up all my server stuff
[23:37] <edmoore> ok, nice idea. do the sums and send an email around
[23:37] <Randomskk> basically depends on how often you run a backup and how long you keep old data
[23:39] <edmoore> gource isn't actually in macports afterall
[23:39] <Randomskk> so all that recompiling was for naught? D:
[23:39] <edmoore> well the svn is pretty mission-critical
[23:39] <edmoore> I sort of think we should maybe shift it to google
[23:40] <Randomskk> or github or anything similar
[23:40] <Randomskk> depends how much you trust srcf.ucam
[23:40] <Randomskk> or rather, trust their systems to not fail
[23:40] <Randomskk> thing about the svn is that, as far as I remember, and I may be totally wrong here, each user's working copy isn't a full mirror of the svn?
[23:41] <Randomskk> i.e. if the server went down, you can't restore from any one person's local copy
[23:41] <edmoore> correct
[23:41] <edmoore> you'd just have a snapshot of their version
[23:41] <edmoore> i don't trust srcf.ucam
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[23:41] <Randomskk> are there any backups in place besides that precariously balanced CD?
[23:41] <edmoore> no
[23:42] <edmoore> i made that cd when srcf went down with a file system error
[23:42] <Randomskk> I wonder if git-svn downloads all the history. I think it does.
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[23:42] <Randomskk> how big is your entire svn directory? `du -hs /path/to/cusf/svn/`
[23:43] <Randomskk> lol jeez my local copy is 1.3GB, the one on the actual server is 537M
[23:44] <Randomskk> and my plain svn copy is.. 1.5GB. huh.
[23:44] <edmoore> i checked out a new w/c today on XP box and it was just over 500MB, yep
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[23:45] <Randomskk> my guess is that git-svn downloads the entire history in order to make it all git-like, and in that case my git local copy is a total mirror but not in a format that could easily be turned back into svn
[23:46] <Randomskk> for reference, storing one month of daily total svn backups (not differentials) would cost $3.80 a month on S3
[23:46] <Randomskk> that's 15GB/mo storage plus 15GB/mo upload
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[23:47] <Randomskk> and pip.srcf has duplicity installed, even. how nice.
[23:47] Nick change: jasonb_ -> jasonb
[23:47] <edmoore> if we got freenas we could just rsync it off pip every so often
[23:49] <Randomskk> duplicity is a higher level backup software that runs on top of rsync
[23:49] <Randomskk> http://duplicity.nongnu.org/
[23:53] <edmoore> ok, I quite like git
[23:53] <Randomskk> it can do all sorts of cool things
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[23:53] <Randomskk> rebasing is neat, the whole distributed thing makes a lot of other neat things possible
[23:54] <Randomskk> even just using it to emulate svn I find it faster and more useful (make lots of small commits locally, push them as one larger commit to some central server you use to collaborate)
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[00:00] --- Tue Nov 10 2009