highaltitude.log.20080320

[00:00] <fuzzylugnut> nope, mild cheddar
[00:01] <Laurenceb> yem
[00:05] <Laurenceb> natrium42: http://www.anthonydeane.com/b3ta/pics/rick.gif
[00:16] <natrium42> hehe
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[01:37] <akawaka> what do you guys use for voltage regulation?
[01:38] <fuzzylugnut> low dropout linear voltage regulators
[01:38] <fuzzylugnut> I'm only going to 7 V to 5, so its not a huge loss.
[01:40] <akawaka> what are you getting the 7 volts from?
[01:41] <fuzzylugnut> 2 A123 batteries. they are 3.3V each
[01:42] <akawaka> little worried about interference from our switched regulator
[01:42] <fuzzylugnut> just out some filter caps in parallel with your supply
[01:43] <fuzzylugnut> *put
[01:43] <fuzzylugnut> not "out" : P
[01:43] <akawaka> electrical engineers ability to throw capacitors around with ease has always amazed me
[01:43] <fuzzylugnut> ...?
[01:44] <akawaka> whenever i did electronic lab work in school
[01:44] <fuzzylugnut> ahh
[01:44] <akawaka> so TA would come by and look at my non-working circuit and pull some farad value out of his ass and make everything better
[01:44] <fuzzylugnut> ahh
[01:45] <akawaka> but i guess, capacitor in series blocks dc, in parallel absorbs ac
[01:45] <fuzzylugnut> Yep
[01:45] <fuzzylugnut> you got it
[01:46] <akawaka> and the farad value isn't super critical, just needs to be good enough
[01:46] <fuzzylugnut> Yep
[01:46] <akawaka> its the thing i'm only just starting to learn about electronics in general
[01:46] <akawaka> big tolerances
[01:46] <fuzzylugnut> ahhh, there are alot of books out there that will help you
[01:46] <akawaka> its always taught as such an exact science
[01:47] <fuzzylugnut> theoretically : )
[01:47] <akawaka> but everyone i know that is good at it seems to use as much instinct as anything else
[01:47] <fuzzylugnut> sometimes you can get away with that, alot of times it really matters.
[01:47] <akawaka> yeah, i'm starting to understand
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[19:18] <akawaka> finally got the radio working with soundmodem in linux
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[19:24] <Hiena> Good evening!
[19:24] <edmoore> ello
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[20:10] <edmoore> hi RocketBoy
[20:12] <RocketBoy> hi ed
[20:12] <edmoore> to answer your email, I'll have to make a few assumptions, but basically the gps is 90mW const
[20:13] <edmoore> the arm is 3.3V 30mA, but that's at max duty cycle which it needed necessarily be at the whole time
[20:13] <RocketBoy> ok - thats good - 3V nominal?
[20:13] <edmoore> and the GSM module can be turned off above 1000m
[20:14] <edmoore> 3.3 iirc
[20:14] <edmoore> nom
[20:14] <edmoore> as for measureing voltage, we're got some spare a2d lines so that's probs ok
[20:14] <RocketBoy> - so thats about 30mA
[20:14] <edmoore> and we can log it when fergus and i finally persuade fat32 into behaving!
[20:14] <RocketBoy> (for the GPS)
[20:14] <edmoore> yeah
[20:14] <edmoore> i'd say about 60mA const
[20:15] <edmoore> all up
[20:15] <edmoore> we have a linear reg though, which will probably take some power too
[20:15] <RocketBoy> thats quite good
[20:15] <edmoore> though we stuck with it as a bit of payload warming probably wouldn't hurt
[20:15] <RocketBoy> yeah
[20:16] <edmoore> we have some space insulation aswell - that alumised mylar stuff :)
[20:16] <edmoore> and a gu box that they sell icecream in - you know the ones? the black polystyrene boxes with the really nice air-tight feal, about 10cm a side
[20:16] <RocketBoy> so say 20mA for the TX - thats 80mA for everything except the camera
[20:16] <edmoore> I reckon one of those boxes would make a lovely payload box
[20:17] <RocketBoy> nope - I havn't seen them
[20:18] <RocketBoy> 10cm sounds cool
[20:19] <fuzzylugnut> cool tiny payload : )
[20:20] <edmoore> they're really high quality
[20:20] <edmoore> the lid makes a nice fffffffft noise as you close it because it's nearly air-tight
[20:20] <fuzzylugnut> and you get ice cream?
[20:21] <RocketBoy> spiffing - can you get them in the supermarkets?
[20:21] <akawaka> fuzzylugnut: do you find soundmodem uses a lot of cpu time?
[20:22] <fuzzylugnut> I've never looked into it
[20:22] <edmoore> yes, tesco and sains carry them for sure
[20:22] <edmoore> RocketBoy: we just got the pcbs for the badgerboard from olimex
[20:22] <RocketBoy> wooo
[20:23] <edmoore> can't wait to get them soldered up and coded up. we're been developing code on a devel board so far, so it theory it works but then when did theory ever count for anything?
[20:23] <RocketBoy> OK I'll swap my ice-cream consumption to gu
[20:23] <edmoore> they make you pay through the nose, but it's worth it
[20:23] <edmoore> the ice cream is damn nice
[20:23] <akawaka> seems to be constantly pegged above 90%
[20:23] <edmoore> and all in the name of science
[20:24] <RocketBoy> absolutly
[20:25] <RocketBoy> woo - i GOTTA GET ME ONE OF THOSE - http://wheresthesausage.typepad.com/my_weblog/2006/10/gu_ice_cream_pr_1.html
[20:26] <edmoore> bingo!
[20:26] <edmoore> sooooooo nice
[20:26] <fuzzylugnut> :o
[20:26] <RocketBoy> looks way cool
[20:26] <fuzzylugnut> thats really cool
[20:26] <edmoore> I couldn't get over how perfect the boxes would be for small payloads
[20:27] <edmoore> covered in space insulation, they'd really look the business
[20:27] <fuzzylugnut> I use aluminum tape.
[20:27] <edmoore> also, with reference to a previous email, I have one of those 18" chutes from aerocon
[20:28] <edmoore> probably lots of weight to be saved from it as it has fairly hardcore ribbon lines
[20:28] <RocketBoy> Ah - OK 18" is good for us
[20:28] <edmoore> and it's camo green which never helps
[20:28] <fuzzylugnut> ouch.
[20:28] <RocketBoy> the think mill ones I can get are orange
[20:28] <RocketBoy> thin
[20:29] <edmoore> that sounds better - I might grab a couple off you if I may!
[20:29] <RocketBoy> I think they are like £5
[20:29] <RocketBoy> OK NP
[20:29] <edmoore> awesome
[20:29] <RocketBoy> It probably worth me getting a few sizes in
[20:30] <fuzzylugnut> you might want to hang a strobe off the bottom as well, one of those cheapie ones that take 1 D battery. It makes it alot easier to see on the way up
[20:30] <RocketBoy> they go from 9" upto 30"
[20:31] <edmoore> yeah that's not a bad idea - I keep wanting to put an ultrabright led on each face and strobe it at, say, 1hz
[20:31] <edmoore> might be useful if we do a dawn launch anyway
[20:32] <RocketBoy> are there any A2Ds on the badger
[20:32] <edmoore> a couple, aye
[20:32] <edmoore> however the philosophy (if you could call it that) is that we'd make a small io board with, say, an avr if we needed stuff like that
[20:32] <RocketBoy> spot on
[20:32] <edmoore> and talk to it over i2c
[20:32] <edmoore> or spi
[20:33] <RocketBoy> yeah
[20:33] <fuzzylugnut> http://www.lapolicegear.com/emstli.html we use 2 of those on each side of the payload. you can canabalize the circuit board and get rid of the casing pretty easily.
[20:34] <edmoore> the board itself is designed to be able to do completely vanilla flights on its own, but mainly serve as the main flight computer on a stack of other boards.
[20:34] <edmoore> for the rest of our CUSF stuff, like the launch rail for the rockoon
[20:35] <edmoore> fuzzylugnut: I would wager that weighs 1-2x what the rest of our payload would weigh :)
[20:35] <fuzzylugnut> lol
[20:35] <edmoore> we're aiming for 150g to be hung underneath the balloon
[20:35] <fuzzylugnut> *is from a group that used to have 12lb payloads*
[20:35] <fuzzylugnut> wow, thats tiiny!
[20:36] <edmoore> RocketBoy: we should include fergus in the atlas emails, I think.
[20:36] <RocketBoy> OK NP
[20:37] <edmoore> fn217 @ cam . ac . uk
[20:37] <RocketBoy> OK - I'll copy him in on the chain so far
[20:38] <edmoore> I think our fat32 problems might be related to using a 1GB+ card
[20:40] <RocketBoy> Should work
[20:40] <RocketBoy> I have FAT32 working on a 2Gb
[20:41] <edmoore> over the slow serial protocol?
[20:41] <RocketBoy> over SPI @ 5MHz
[20:42] <edmoore> ok, ferg and I are just being dopey then
[20:42] <edmoore> will keep faffing
[20:42] <RocketBoy> are you using someone elses code or your own
[20:42] <RocketBoy> ?
[20:42] <edmoore> someone elses
[20:42] <edmoore> fatfs
[20:42] <edmoore> and trying to run it with TNKernel
[20:43] <RocketBoy> OK
[20:43] <RocketBoy> I guess that is where the gumstix wins (but not on size/power)
[20:43] <RocketBoy> is TNKkernal PD?
[20:43] <edmoore> public domain? yeah
[20:44] <edmoore> yeah, having an off the shelf linux thing is a boon
[20:44] Action: RocketBoy thinks will it run on my PIC
[20:44] <edmoore> still, once we have this stuff all set up it should be a lot easier
[20:44] <fuzzylugnut> haha
[20:44] <edmoore> it's certainly been prted to dspics
[20:44] <edmoore> ported*
[20:45] <edmoore> and it's real time which is an advnatge over the linux kernel
[20:46] <RocketBoy> BTW - I havn't given up with HARVe - the new parafoil turned up the other day - but its either been to rainy + wind or dry + no wind
[20:46] <edmoore> yeah, sounds about right
[20:46] <RocketBoy> I did fly it for about 1/2 hour
[20:46] <edmoore> I've been thinking about it a lot, but only in terms of simulations and maths. nothing all that useful :)
[20:46] <edmoore> so it's under motor control?
[20:47] <RocketBoy> nope - not yet 1st stage is to fly it as a kite to get some pictures of the shape in flight
[20:47] <edmoore> ok
[20:47] <RocketBoy> then re-string it to a paraglider
[20:48] <RocketBoy> I wrote a spreadsheet to do all the 3D line calculations
[20:48] <RocketBoy> The way the lines are made you can remove them and replace them with ouher lengths
[20:49] <RocketBoy> other
[20:49] <RocketBoy> so no need to destroy the kite
[20:49] <edmoore> that's good
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[20:54] <edmoore> just imagine the day - we have 2 HARVes, dropped a second apart, and the 2nd films the first one in flight all the way down
[20:54] <fuzzylugnut> that'd be really cool : )
[20:54] <RocketBoy> uber cool
[20:55] <edmoore> one day!
[20:56] <fuzzylugnut> : )
[20:57] <RocketBoy> BBL - I need to tidy up the workshop
[20:57] <edmoore> I was just thinking about doing that
[20:57] <edmoore> Micahel Palin wins
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[20:58] <fuzzylugnut> get that creepy guy from "black books"
[20:58] <fuzzylugnut> to help : )
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[21:11] <mc-> Rocketboy, do you know of a good antenna for the 30m band?
[21:23] <edmoore> he just went to tidy his garac, mc-
[21:23] <edmoore> got the pcbs today - thank you!
[21:23] <edmoore> can't wait to get things soldered up
[21:25] <mc-> 1st class post actually works
[21:25] <edmoore> I know, amazing
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[21:43] <Daviey> Hey, Little bit OT - any recommendations on a board that contains RJ45, RS-232 and GPRS modem?
[21:43] <Daviey> (and runs Linux)
[21:43] <Daviey> embedded
[21:44] <edmoore> nothing with all three off the top of my head. The gprs requirement might narrow your options
[21:46] <Daviey> :(
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[21:46] <edmoore> sure you couldn't deal with a generic linux SBC and add a gprs modem seperately?
[21:47] <Daviey> via serial?
[21:47] <edmoore> yeah
[21:47] <Daviey> so i'd need two serials
[21:47] <Daviey> thats no problem, but any boards in mind
[21:47] <Daviey> ?
[21:48] <edmoore> well there are a afgidillian small boards with ethernet and rs232 that run linux
[21:48] <Daviey> ARM based?
[21:48] <edmoore> some are - is that a preference?
[21:48] <Daviey> i386 is my real preference :)
[21:49] <Daviey> afgidillian <-- is there a spelling error in that?
[21:49] <edmoore> lol
[21:49] <edmoore> afgillian = 10^lots
[21:49] <Daviey> doh!
[21:49] <Daviey> <-- tired
[21:52] <Daviey> http://www.moxa.com/product/Thinkcore_W345.htm
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[23:19] <Laurenceb> hello me hearties
[23:23] <akawaka> hey
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[23:46] <Laurenceb> hey folks
[23:46] <Laurenceb> RocketBoy: we might be aiming for a launch after easter
[23:47] <edmoore> A launch before Easter would be impressive......
[23:47] <Laurenceb> ha
[23:47] <RocketBoy> 29th/30th?
[23:48] <RocketBoy> or later?
[23:48] <Laurenceb> maybe... need to speak with a few guys
[23:48] <Laurenceb> I'm going home at the weekend
[23:48] <Laurenceb> but really it needs painting, and we need to do a couple more checks of the firmware
[23:48] <RocketBoy> NP
[23:49] <Laurenceb> hopefully Dan (my supervisor) can do that
[23:50] <Laurenceb> do you know the pinout for your radio module?
[23:51] <Laurenceb> oh wow http://www.youtube.com/watch?v=QRXNcQ8q3cA
[23:53] <Laurenceb> ^ didnt know there were videos of that
[23:53] <RocketBoy> red = +3V (or more), black = 0V, white is also 0V - I think orange is RXD (but it might be blue) - its whatever one is connected to the series protection resistor
[23:54] <Laurenceb> thanx
[23:54] <edmoore> the antonov is bigger than the shuttle stack
[23:54] <edmoore> wow
[23:56] <Laurenceb> its so annoying how so much work goes into things then they just get forgotten
[23:56] <Laurenceb> :(
[23:56] <edmoore> like the Mriya?
[23:56] <Laurenceb> yes
[23:56] <edmoore> It was my favourite aeroplane for a while
[23:56] <edmoore> when I was 10
[23:56] <Laurenceb> and the X33
[23:57] <edmoore> and had a copy of Jane's Aircraft Recognition Guide
[23:57] <edmoore> it was the biggest thing in there
[23:58] <Laurenceb> ah cool, I've got eagle working in ubuntu
[23:58] <edmoore> apt get install eagle?
[23:58] <edmoore> worked for me...
[23:58] <Laurenceb> nah
[23:58] <Laurenceb> the graphics were screwed
[23:59] <Laurenceb> had to write a little script to boot it correctly
[00:00] --- Fri Mar 21 2008