highaltitude.log.20060430

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[00:19] <HenryHallam> laters
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[02:14] <macfreak4> hey
[02:14] <defy> hey :)
[04:45] <macfreak4> well am i having a fun time or what
[04:45] <macfreak4> ugh'
[05:12] <defy> lol whats up
[05:28] <macfreak4> well its just disappointing that a pentium ii can't even record 320x240 at 15 frames per second
[05:29] <macfreak4> video, that is
[05:29] <macfreak4> the best i can do is 160x120 at somewhere near 15fp
[05:29] <macfreak4> fps*
[05:29] <macfreak4> :(
[05:29] <macfreak4> but i g2g
[05:30] <macfreak4> sleep sleep ;)
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[12:20] <HenryHallam> morning
[12:23] <jcoxon> morning HenryHallam
[12:24] <HenryHallam> ugh, product design coursework... "Design a product to assist the elderly with their shopping"
[12:24] <jcoxon> a jet powered trolley
[12:24] <HenryHallam> everyone's doing a bloody trolley
[12:24] <HenryHallam> heh
[12:25] <HenryHallam> with anti-mugger flamethrowers perhaps
[12:25] <jcoxon> just had to reflash my gumstix
[12:25] <jcoxon> oops
[12:25] <jcoxon> all working now
[12:28] <HenryHallam> does it come with a separate programmer to reflash it if all goes FUBAR or is it a bootloader that runs on startup?
[12:29] <jcoxon> it has uboot, so i logged in via serial console ( i usually usbnet in)
[12:29] <jcoxon> and uploads a fresh image
[12:29] <jcoxon> then once reflashed i ssh back in and put it back to how it was
[12:30] <HenryHallam> right
[12:30] <HenryHallam> it does look like a very neat bit of kit
[12:31] <HenryHallam> do you think radiation is an issue for computers up there?
[12:31] <jcoxon> no sure
[12:31] <jcoxon> what issue would it cause?
[12:32] <HenryHallam> memory corruption mainly
[12:32] <HenryHallam> can be compensated for with ECC ram
[12:32] <jcoxon> could well be an issue for long duration flights
[12:32] <HenryHallam> all the main Shuttle and ISS systems use expensive, slow rad-hardened chips
[12:33] <jcoxon> also the low pressure causes gases to leave the chips
[12:33] <HenryHallam> but the astronauts also take what I think are pretty much stock laptops up there and those seem to work fine
[12:33] <HenryHallam> really, that's interesting
[12:33] <jcoxon> i got told about it
[12:33] <jcoxon> i'll get a link
[12:33] <HenryHallam> maybe it'll need a pressurised bay
[12:40] <jcoxon> hmm can't seem to find hte link
[12:43] <jcoxon> found it:
[12:43] <jcoxon> http://en.wikipedia.org/wiki/Outgassing
[12:46] <jcoxon> brb
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[12:58] <HenryHallam> hm, looks like it might be an issue for the camera in particular
[12:59] <jcoxon> will require testing
[12:59] <HenryHallam> my hunch is it won't affect the chips very much though
[12:59] <jcoxon> i don't think the pressure is low enough
[13:00] <HenryHallam> could put the electronics in an oven to about 120 C for an hour or two, then stick some silica gel in there, that should get rid of most of the adsorbed water
[13:00] <jcoxon> well as long as we recognise its a risk then i don't think we need to worry
[13:00] <HenryHallam> I have a high vacuum rig at home that I could run a few experiments on next time I'm down there
[13:00] <HenryHallam> I've never put any electronics in it before
[13:00] <jcoxon> we also have access in the department i think
[13:02] <HenryHallam> right, that would be easier
[13:07] <HenryHallam> it'd be nice to carry a pressure sensor
[13:07] <HenryHallam> the good ones are £100+ even second hand, though
[13:39] <jcoxon> right off to play hockey
[13:39] <jcoxon> chat later
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[15:53] <Tiger^> hello :)
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[16:36] <jcoxon> hey all
[16:37] <icez> hey
[16:39] <jcoxon> hey Tiger^
[16:39] <jcoxon> someone new :-D
[16:42] <Tiger^> hullo, jcoxon :)
[16:42] <Tiger^> yeah, I'm launching my balloon in a month :)
[16:44] <jcoxon> ooo cool
[16:44] <jcoxon> where from?
[16:44] <Tiger^> i've read about your Pegasus project, very interesting. I'm taking a little different approach, though.
[16:44] <Tiger^> jcoxon: Poland. Warsaw, to be exact :)
[16:44] <jcoxon> cool
[16:44] <jcoxon> you using radio?
[16:45] <Tiger^> yup, vhf radio and a self-built FSK modem for telemetry
[16:45] <Tiger^> and a GSM phone as a backup
[16:45] <jcoxon> cool
[16:45] <Tiger^> my first flight computer will be microcontroller based
[16:46] <jcoxon> i would use the radio approach if i could
[16:46] <jcoxon> good idea
[16:46] <jcoxon> do you have a website?
[16:46] <Tiger^> if i'm able to recover the payload, i'll send linux up :)
[16:46] <jcoxon> hehe i'm sure you will
[16:46] <Tiger^> why can't you use the radio? no license? ;/
[16:47] <jcoxon> oh no its just the licence says you can't have unmanned airbourne radios
[16:47] <Tiger^> nope, no website yet. i'll put something up after the flight
[16:47] <jcoxon> cool
[16:47] <Tiger^> hmm, weird
[16:47] <jcoxon> send me the link when you do
[16:47] <Tiger^> i will
[16:47] <jcoxon> there are ways around it
[16:48] <jcoxon> i'm looking into licence free radio modems
[16:48] <Tiger^> oh, you mean the ISM ones? :)
[16:48] <Tiger^> Industrial, Science, Medical band/power?
[16:49] <jcoxon> perhaps
[16:49] <HenryHallam> Hi there
[16:50] <HenryHallam> it would be interesting to do some free-air range testing of those license free modules with semi-directional antennae
[16:50] <jcoxon> yeah
[16:50] <HenryHallam> because I don't think the quoted range is likely to be very accurate, the antenna will determine a lot of it
[16:51] <Tiger^> i'm afraid the power's too low
[16:51] <HenryHallam> ah
[16:51] <Tiger^> even for a high gain ant
[16:51] <HenryHallam> sounds like you know a bit about this radio stuff!
[16:51] <Tiger^> these modules have, what, 10dBm = 10mW
[16:52] <HenryHallam> what about using the 2.4Ghz band? you're allowed up to 250mW on that aren't you?
[16:52] <jcoxon> still have this :-D http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=7614300574&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1
[16:52] <Tiger^> HenryHallam: i'm not a pro, but I'm into amateur radio and stuff since 1993 :)
[16:52] <HenryHallam> that's great, we can bug you with lots of questions then ;)
[16:53] <Tiger^> HenryHallam: hmm, 250mW? i don't remember, but it seems too much
[16:53] <Tiger^> have to check the EU regulations ;)
[16:53] <HenryHallam> what power are Wifi hotspots? is that 10mW too?
[16:54] <Tiger^> HenryHallam: it's all about EIRP
[16:54] <Tiger^> that's Effective Isotropic Radiated Power
[16:54] <Tiger^> it's the transmitter's power and the antenna gain
[16:55] <HenryHallam> so does that mean that with a high gain antenna you're not allowed as much power?
[16:55] <Tiger^> the maximum EIRP for wifi devices is 20dBm in the EU, if I remember correctly
[16:55] <Tiger^> HenryHallam: yup
[16:56] <HenryHallam> would that be equivalent to 100mW with an omni antenna?
[16:57] <jcoxon> this is still what i'm looking at http://www.bfioptilas.co.uk/OEM_Modules-g5659.htm
[16:57] <Tiger^> HenryHallam: well, there are quite a few kinds of omni antennae available
[16:58] <Tiger^> HenryHallam: you'd have to calculate it :)
[16:58] <jcoxon> right i've got to go, but will be back on later this evening
[16:58] <jcoxon> cya
[16:58] <Tiger^> based on the antenna gain
[16:59] <HenryHallam> right, so even a fully omni antenna can have some gain?
[16:59] <Tiger^> jcoxon: cya, i'll take a look on those oem modules :)
[16:59] <jcoxon> cool
[16:59] <HenryHallam> later james, though you might check this out before you go: http://cgi.ebay.co.uk/NEW-Thuraya-Hughes-7101-SATELLITE-Phone-LATEST-VERSION_W0QQitemZ9129573844QQcategoryZ42428QQrdZ1QQcmdZViewItem
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[16:59] <Tiger^> HenryHallam: that's right, the gain is relative to an idealised isotropic antenna with 0dB gain :)
[17:00] <HenryHallam> okay, that makes sense
[17:00] <HenryHallam> thanks
[17:01] <Tiger^> the equation for EIRP is:
[17:01] <Tiger^> EIRP = 10 * log10(P/1mW)
[17:02] <Tiger^> P = radiated power
[17:02] <Tiger^> don't be scared, i don't know anything about logarithms, so i use a calculator :)
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[17:02] <HenryHallam> hehehe
[17:03] <Tiger^> anyway, it'd be interesting to send wifi up
[17:03] <Tiger^> and see how (if) it works
[17:03] <HenryHallam> would you measure P with a wattmeter in the highest intensity location?
[17:03] <HenryHallam> Hi malgar
[17:03] <Tiger^> HenryHallam: that's right
[17:03] <HenryHallam> ok
[17:03] <Tiger^> but there's more to it:
[17:04] <Tiger^> and there's more to it, the transceiver/antenna set has to have homologation
[17:04] <Tiger^> which basically means, no antennae other than the thing you bought with your wifi device
[17:05] <HenryHallam> oh
[17:05] <HenryHallam> I suppose all those pringles can antennae are illegal then
[17:06] <Tiger^> yes they are
[17:07] <Tiger^> but no one cares, unless there's RF interference
[17:09] <HenryHallam> oh if I were just doing this as a personal project I'd use a big old 10W transmitter and damn the regulations, but the intention is to make it look "professional" and that probably means playing by the rules
[17:09] <malgar> hi HenryHallam
[17:09] <HenryHallam> hi there
[17:10] <Tiger^> HenryHallam: a 500, even a 350mW transmitter would do fine :)
[17:13] <HenryHallam> really, even with only semidirectional antennae?
[17:13] <HenryHallam> would you need a very good ground receiver for that?
[17:13] <Tiger^> even for omni :)
[17:13] <Tiger^> it's amazing how line-of-sight radio communication works
[17:14] <HenryHallam> not bad
[17:14] <Tiger^> you don't need much power at all if there are no obstacles
[17:15] <Tiger^> in the US, guys send small Alinco or Yaesu UHF handheld transceivers
[17:15] <HenryHallam> oh, speaking of obstacles, are there any plastics that are very transparent to radio? I suppose it varies with frequency
[17:15] <Tiger^> those babies have no more than 300-500mW.
[17:16] <Tiger^> hmm, nothing is completely transparent to radio at vhf/uhf freqs
[17:16] <Tiger^> the best bet is to keep the antenna outside
[17:17] <HenryHallam> ok
[17:17] <HenryHallam> does that go for cell phone and gps as well?
[17:18] <Tiger^> nope, GSM phone = quite a few high-power BTSs for the phone to choose
[17:18] <Tiger^> and GPS = quite a few high-power sats hanging above :)
[17:19] <Tiger^> i've got another problem when it comes to a cell phone and a GPS
[17:19] <HenryHallam> oh?
[17:19] <Tiger^> i haven't decided yet what to use as the payload's airframe
[17:19] <Tiger^> so i'm building two airframes
[17:20] <Tiger^> one is a modified simple lunch bag
[17:20] <HenryHallam> heh
[17:20] <HenryHallam> for NOVA we're going with a 30cm cube where each face is a detachable module
[17:20] <Tiger^> yeah, and that's my second approach
[17:20] <Tiger^> a styrofoam cube
[17:21] <Tiger^> (not the low grade packaging styrofoam, though, but XPS)
[17:21] <Tiger^> that's extruded polystyrene
[17:22] <Tiger^> anyway,
[17:22] <Tiger^> if i choose to go with the styrofoam box
[17:22] <HenryHallam> is that the fine-grain stuff? better insulating?
[17:22] <Tiger^> (that's the stuff where you don't see the grain :) much better)
[17:23] <Tiger^> i'll need even more thermal isolation
[17:23] <Tiger^> and the best thing there is, is aluminized mylar
[17:23] <HenryHallam> hmm
[17:23] <Tiger^> a space blanket
[17:24] <Tiger^> and aluminized mylar blocks radio reception :)
[17:24] <HenryHallam> well that stuff would certainly be best at preventing radiative heat loss, but I would have thought foam would be better for conductive heat loss
[17:24] <HenryHallam> ah right, that too
[17:24] <HenryHallam> have you thought about putting one of those chemical hand warmer packs in there to keep the electronics warm?
[17:25] <HenryHallam> then insulation isn't such a concern
[17:25] <Tiger^> i'm not that worried about the electronics getting cold
[17:25] <Tiger^> most of my components are rated down to -40 C
[17:25] <Tiger^> i'm worried about condensation :(
[17:26] <Tiger^> and i can't make the payload airtight, 'cause i think it'll fall apart when the pressure drops low enough
[17:27] <HenryHallam> airtight but with a small vent?
[17:27] <HenryHallam> put some packets of silica gel in there
[17:27] <Tiger^> yeah, something like a cork
[17:27] <HenryHallam> if you don't launch through cloud I wouldn't have thought condensation would be that big an issue
[17:27] <HenryHallam> because it's not like you're putting a cold surface into warm moist air, the air is already cold and doesn't have much water in it so you're just providing a nucleation site
[17:28] <Tiger^> i'm afraid i won't be able to talk the clouds into leaving the launch area ;)
[17:28] <Tiger^> yeah, so it won't be a problem on ascent
[17:28] <Tiger^> but what about descent?
[17:29] <HenryHallam> hmm
[17:29] <Tiger^> it'll cool rapidly from -40 to about 18-20 degrees
[17:29] <Tiger^> i mean warm
[17:29] <HenryHallam> until it gets down to the cloud layer I wouldn't expect many issues
[17:30] <HenryHallam> falling through cloud might get a bit damp though
[17:30] <HenryHallam> lots o' silica gel?
[17:30] <Tiger^> that's what i'm worried about
[17:30] <Tiger^> maybe...
[17:31] <Tiger^> i'm surprised that nobody really takes condensation problems seriously
[17:31] <Tiger^> or at least they don't talk about it
[17:32] <HenryHallam> well
[17:32] <Tiger^> it's like, everybody keeps telling how important it is to wrap the electronics in a plastic bag for the frige/freezer test
[17:32] <HenryHallam> hell why don't you just do that?
[17:32] <Tiger^> but not a word about the real flight
[17:32] <HenryHallam> in a light aircraft flying through clouds you don't get any condensation in the cabin, which is definitely not anything close to airtight or watertight
[17:32] <Tiger^> because it'll get too hot and fail
[17:33] <HenryHallam> oh are you using a powerful transmitter then?
[17:33] <Tiger^> nope, nothing *that* powerful, except for the cutdown device ;)
[17:34] <HenryHallam> I think you should be able to have a watt or two of heat output in a plastic bag and not melt anything
[17:34] <Tiger^> but even the LM voltage regulator gets so warm, it needs a heatsink
[17:34] <Tiger^> dunno... the guy, what was his name...
[17:34] <Tiger^> nevermind
[17:35] <HenryHallam> sure it gets to a high temperature because it's a tiny chip
[17:35] <Tiger^> the guy who launched "Balloon v1.0"
[17:35] <Tiger^> used a lunch bag
[17:35] <Tiger^> and internal temperature didn't get below 36-45 C
[17:36] <Tiger^> and i don't want my electronics to get any warmer
[17:36] <HenryHallam> most components are rated up to at least 80 C aren't they?
[17:37] <HenryHallam> you can reduce the heat output quite a bit if you use a switching regulator instead of a linear one
[17:37] <HenryHallam> they're not too expensive and will extend battery life too
[17:38] <Tiger^> most components are, yeah
[17:38] <Tiger^> but, for example, anything more than 60 degrees
[17:38] <Tiger^> and the xtal output becomes unstable
[17:39] <Tiger^> that's a thing to consider
[17:39] <Tiger^> i thought about a step-up/down converter from Maxim
[17:39] <Tiger^> but they're all SMD
[17:39] <Tiger^> and i don't want to use SMD
[17:40] <HenryHallam> don't be scared of SOIC, it's really easy to solder, the smaller ones get a bit trickier
[17:40] <HenryHallam> are you using a 5V system?
[17:40] <Tiger^> uh, you know, I'm really not good enough in soldering smd :)
[17:41] <Tiger^> the only SMD chip i'm going to use is a SO16 FSK modem
[17:41] <Tiger^> and that's only because i couldn't get a DIL version
[17:41] <Tiger^> yup, 5V
[17:42] <Tiger^> and the cells give 9V.
[17:42] <Tiger^> if i used a step-up/down converter i could probably stick with 6V from the cells
[17:42] <Tiger^> (and less power wasted = less heat)
[17:43] <Tiger^> but LMs are step-down only regulators
[17:43] <HenryHallam> the LM2825N is really nice
[17:43] <HenryHallam> 7 to 40V in, no external components, 80% efficient
[17:43] <HenryHallam> and DIL
[17:44] <HenryHallam> quite expensive new but I was lucky enough to pick up two of them on ebay for £1 last month
[17:44] <HenryHallam> I don't know if they'll come up again
[17:44] <Tiger^> about $33 new
[17:44] <HenryHallam> ouch
[17:44] <Tiger^> yeah ;)
[17:45] <Tiger^> and it's step-down only
[17:45] <HenryHallam> it's overkill for 500mW anyway though
[17:45] <HenryHallam> I've also heard about some drop-in replacements for the 7805 but I don't know any part numbers for those
[17:46] <Tiger^> i'm using the 2940
[17:46] <Tiger^> low drop version
[17:46] <HenryHallam> what I meant to say earlier was that just because one voltage regulator IC is getting to 100 degrees that doesn't mean the other parts will, even if they're inside the same plastic bag
[17:46] <Tiger^> take a look this one: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1742
[17:46] <Tiger^> SMD, though :/
[17:46] <HenryHallam> or if you do think it's all going to put out a lot of heat, use that heat to keep it warm and non-condensy
[17:47] <HenryHallam> only SOIC though, not too hard to solder at all
[17:47] <HenryHallam> 1.27mm pitch
[17:47] <Tiger^> HenryHallam: yeah, i hope the heat generated by the batts, the radio, the flight computer etc. will keep the box warm
[17:48] <HenryHallam> I'd never soldered anything with SMT until quite recently and generally my soldering skills are pretty poor but it's really not difficult
[17:48] <HenryHallam> as long as you have an actual PCB to solder it to
[17:48] <HenryHallam> even homemade PCB is fine but use tinning chemical
[17:49] <Tiger^> hmm
[17:49] <HenryHallam> besides, it's Maxim, they send you 3 spares to practice on along with the real one, for nothing :P
[17:49] <Tiger^> yeah, i know
[17:49] <Tiger^> but i'm still sceptical ;P
[17:50] <HenryHallam> the solder sticks to the tracks, surface tension is great
[17:50] <Tiger^> but you have to be sooo careful not to make solder bridges
[17:51] <HenryHallam> not really
[17:51] <HenryHallam> if you make one you can fix it without much difficulty
[17:51] <HenryHallam> either with one of those spring solder sucker things or just a screwdriver
[17:52] <Tiger^> yeah
[17:52] <HenryHallam> http://www.infidigm.net/articles/solder/ this looks like a reasonable guide
[17:53] <HenryHallam> I try to avoid anything smaller than SOIC, you start to need special soldering iron tips or solder paste
[17:53] <Tiger^> yes, i've read it
[17:53] <HenryHallam> get an old PCB from something to practice on
[17:53] <HenryHallam> though it's much easier when you have a fresh chip and solder
[17:53] <Tiger^> hehe, i'm not touching anything smaller than DIL with a three-foot pole
[17:54] <Tiger^> or at least i didn't until now ;P
[17:54] <Tiger^> i'm thinking about this special smd paste
[17:55] <HenryHallam> I haven't used it myself but I wouldn't bother for SOIC
[17:56] <HenryHallam> I mean you don't even need a steady hand or a good soldering iron or decent eyesight
[17:56] <Tiger^> if you say so...
[17:57] <HenryHallam> trust me, I have none of those ;)
[17:57] <Tiger^> ok, i'll hold you personally responsible if my $15 FSK modem chips turn into a melted pulp of plastic and solder! ;)
[17:58] <Tiger^> oh, and there's one more thing
[17:58] <HenryHallam> haha
[17:58] <Tiger^> i'm worried about these things being ripped from the pcb
[17:58] <Tiger^> by a stray piece of foam padding
[17:58] <Tiger^> or something else
[17:58] <HenryHallam> umm
[17:59] <HenryHallam> they're on there pretty tight
[17:59] <HenryHallam> you ever tried to pry one off?
[17:59] <Tiger^> you mean, one soldered by an industrial SMD soldering machine
[17:59] <Tiger^> or by myself? :D
[17:59] <HenryHallam> heh
[17:59] <HenryHallam> I wouldn't worry
[18:00] <Tiger^> the former are almost imposible to pry off
[18:00] <HenryHallam> especially with anything that has more than a couple of pins
[18:00] <Tiger^> without ripping the pads from the chip
[18:00] <Tiger^> ok
[18:00] <Tiger^> so i'll try
[18:00] <Tiger^> :)
[18:00] <HenryHallam> great
[18:00] <HenryHallam> how are you making the PCB?
[18:00] <Tiger^> really great, because this Maxim converter is a great chip
[18:01] <Tiger^> i'm laying out the tracks in Eagle
[18:01] <Tiger^> and usually i make my pcbs at home
[18:01] <HenryHallam> right, same here
[18:01] <HenryHallam> photo etching presumably?
[18:02] <Tiger^> yeah
[18:02] <HenryHallam> right
[18:02] <Tiger^> much better results than this laser printer stuff
[18:02] <HenryHallam> do use a tinning chemical on the board, it makes the soldering a lot easier and looks prettier too
[18:02] <HenryHallam> trust me, you'll be loving SMD by the time this is done
[18:03] <Tiger^> ;)
[18:03] <Tiger^> i thought about sending my layouts to a commercial pcb house this time
[18:04] <HenryHallam> it's soo expensive though
[18:04] <Tiger^> expensive? :) hmm
[18:04] <Tiger^> i found a good pcb house here in warsaw
[18:05] <Tiger^> they take, hm,
[18:05] <Tiger^> like, $1 for 10 square cm
[18:06] <Tiger^> and additional $10 for each layout
[18:06] <HenryHallam> well that's not too bad for a commercial place but home etching gets you about 10 times as much area for your money
[18:06] <Tiger^> i know
[18:06] <HenryHallam> http://www.pulsar.gs/PCB/a_Pages/3_Direct_Etch/3c_How_Fine_A_Line/How_Fine_A_Line.html this laser printer system looks a cut above the rest of them, impressive results though I haven't used it myself
[18:07] <Tiger^> hm
[18:07] <HenryHallam> I'll stick with my photo setup though
[18:08] <HenryHallam> btw tracing paper works much better than acetate
[18:08] <Tiger^> i haven't decided yet, but i want everything to be really robust for my first flight :)
[18:09] <HenryHallam> why not etch it at home, give it a good beating and if it fails send off for a professional board
[18:09] <Tiger^> yup, that's probably what i'm going to do
[18:10] <HenryHallam> while you're at it, etch a board with a bunch of SOIC pads and order some free samples of any old chip to practice on
[18:13] <Tiger^> yeah, i've got some old soic chips here
[18:14] <HenryHallam> though I can't get the damn maxim sample site to work at the moment
[18:26] <HenryHallam> right I'm off, got to do some homework
[18:27] <HenryHallam> nice talking to you
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[19:49] macfreak4 (n=macfreak@24-107-201-22.dhcp.stls.mo.charter.com) joined #highaltitude.
[19:49] <macfreak4> hey
[20:21] HenryHallam (n=H@natreg.pem.cam.ac.uk) joined #highaltitude.
[20:22] <HenryHallam> Hi again gang
[20:22] <macfreak4> hi
[20:23] <HenryHallam> well I didn't get much homework done but I did draw a funky block diagram for the nova tracker
[20:24] <macfreak4> the ground tracker?
[20:25] <HenryHallam> no, the onboard one
[20:25] <HenryHallam> GPS module + PIC + GSM phone
[20:25] <macfreak4> ooh k
[20:26] <macfreak4> so you guys are going to use a PIC on the nova then
[20:26] <macfreak4> for what you're going 2 b doing that should make things much better
[20:26] <HenryHallam> definitely on the first one, and possibly on subsequent ones as a sort of reliable baseline
[20:26] <HenryHallam> it can feed position data to a gumstix or whatever if necessary
[20:26] <macfreak4> less weight for batteries, smaller size and weight itself, etc.
[20:26] <macfreak4> yea
[20:27] <HenryHallam> well the gumstix is pretty damn small too, I think the main advantage is simplicity + reliability
[20:27] <macfreak4> yeah well thats true too
[20:27] <HenryHallam> not that embedded linux systems can't be reliable, but there are fewer things to go wrong with a PIC
[20:28] <macfreak4> yeah because i guess w/ a pic you don't need to deal with an operating system -- what you program is exactly what it does
[20:28] <Tiger^> the KISS rule ;)
[20:28] <HenryHallam> exactly
[20:28] <HenryHallam> I'm going to try and build in as many failsafes as possible into the software
[20:29] <Tiger^> with wifi though, one board linux boxes are the only choise
[20:29] <Tiger^> choice
[20:29] <HenryHallam> oh sure
[20:29] <macfreak4> ya
[20:29] <Tiger^> it'd be hard to code wifi stack into an avr or a pic
[20:29] <HenryHallam> yeah, maybe possible but not worth the effort
[20:29] <Tiger^> right
[20:29] <macfreak4> well its pretty much impossible seeing how there really isnt a way to get USB or LAN on a pic, which is how WiFi works
[20:30] <HenryHallam> someone did a TCP/IP stack and webserver in a PIC a couple of years back
[20:30] <macfreak4> hmm must have been a pretty decent pic
[20:30] <HenryHallam> but it would be so much overhead that it's probably fairly pointless
[20:30] <macfreak4> there are so many different pics -- its crazy
[20:30] <Tiger^> yeah, there's a TCP/IP stack for AVR and for '51s
[20:30] <HenryHallam> no I think it was a 16F84 or something
[20:30] <macfreak4> oh?
[20:31] <macfreak4> *is doing a search*
[20:31] <HenryHallam> http://www.kyllikki.org/hardware/wwwpic2/
[20:31] <macfreak4> o thx
[20:31] <Tiger^> but it's scratching your left ear with your right foot ;)
[20:32] <HenryHallam> hah, indeed
[20:32] <macfreak4> unless im reading this wrong its communicating over a serial connection
[20:32] <macfreak4> LAN - SERIAL - PIC
[20:33] <HenryHallam> hm looks like you're right
[20:33] <macfreak4> yeah so by that point you might as well use a packet modem
[20:33] <HenryHallam> http://members.vol.at/home.floery/electronix/picnic/ this one does it using a NIC
[20:34] <HenryHallam> but it's still silly
[20:34] <macfreak4> yes
[20:34] <macfreak4> very
[20:34] <macfreak4> :)
[20:34] <HenryHallam> I think a satellite phone might be the solution to our radio-licensing woes
[20:34] <Tiger^> hm
[20:34] <macfreak4> if you have the resources
[20:34] <macfreak4> they are VERY expensive
[20:35] <HenryHallam> looks like they can be got on ebay with some prepaid credit for around $400-$500
[20:35] <Tiger^> HenryHallam, are you positively sure you can't fly a VHF radio?
[20:35] <HenryHallam> which might just about be within the budget assuming we don't break it
[20:35] <macfreak4> or lose it
[20:35] <Tiger^> indeed
[20:35] <HenryHallam> Tiger, I'm not 100% sure but it's looking that way
[20:35] <HenryHallam> at least one in the right power range
[20:36] <HenryHallam> certainly as an amateur you can't, even if you get all the ham licences
[20:36] <Tiger^> HenryHallam: hmm, there's a group in Poland, that launches in June
[20:36] <HenryHallam> it's a UK thing, the rest of Europe is much more relaxed
[20:36] <Tiger^> HenryHallam: and they got a license for unmanned radio operation
[20:36] <Tiger^> oh
[20:37] <HenryHallam> we might be able to pull something because we have the assosciation with the university
[20:37] <HenryHallam> but even if that were possible, paying for a radio licence might cost a whole lot
[20:37] <HenryHallam> a commercial licence that is
[20:37] <macfreak4> could you get a different kind of lisence, besides an amateur, that would allow unmanned stations in a different band?
[20:38] <macfreak4> oh lol
[20:38] <macfreak4> just said that...
[20:38] <HenryHallam> yeah I think that's our only hope really if we want to use a VHF radio
[20:38] <macfreak4> yeah
[20:38] <macfreak4> thats a big bummer
[20:39] <Tiger^> i've got an idea
[20:39] <Tiger^> do you have LPD/PMR in the UK?
[20:39] <Tiger^> i mean, is it legal?
[20:40] <HenryHallam> I don't even know what those stand for :P
[20:40] <Tiger^> run a quick google search on that ;)
[20:40] <Tiger^> look for PMR, first
[20:40] <HenryHallam> k
[20:40] <Tiger^> it's something like Portable Mobile Radio, or some crap like that
[20:41] <Tiger^> Personal :)
[20:41] <Tiger^> since "portable mobile" doesn't make much sense.
[20:42] <HenryHallam> hmm, half a watt
[20:42] <Tiger^> yeah
[20:42] <HenryHallam> I think there's something in the regs about no unmanned stations though
[20:42] <Tiger^> hey
[20:43] <Tiger^> these are regulations about licensed radios
[20:43] <Tiger^> PMR is completely license free
[20:44] <Tiger^> if the regs prohibit unmanned radios completely
[20:44] <Tiger^> your national weather service wouldn't be allowed to send RS-80 Radiosondes up
[20:44] <Tiger^> and i'm pretty damn sure they do send them
[20:45] <HenryHallam> yes, they do, but they're operated by the military
[20:45] <HenryHallam> http://www.ofcom.org.uk/static/archive/ra/publication/ra_info/ra357.htm this page doesn't mention anything about unmanned
[20:46] <Tiger^> so... :)
[20:46] <HenryHallam> do you think we'd get 50km free-air range with a set of PMR radios then?
[20:46] <HenryHallam> hell
[20:46] <HenryHallam> one way to find out
[20:47] <Tiger^> you may be stretching it a little
[20:47] <Tiger^> the problem is
[20:47] <Tiger^> everybody and their dog use PMR
[20:48] <HenryHallam> well their dog can switch to another channel if he gets bothered by a text-to-speech readout every 5 minutes
[20:48] <Tiger^> their dog, yeah
[20:49] <Tiger^> but you have to figure a way to switch channels
[20:49] <Tiger^> if for example you can get through to the balloon
[20:50] <Tiger^> sorry
[20:50] <Tiger^> the other way
[20:50] <Tiger^> the balloon can get through to you
[20:50] <Tiger^> but you cannot get through to the balloon
[20:50] <Tiger^> it can happen even in the 2m band
[20:51] <Tiger^> because your antenna on the ground "sees" only the balloon and ten-twenty stations in your range
[20:51] <HenryHallam> but the balloon sees a lot more stations
[20:51] <Tiger^> but the balloon has direct line of sight communication with stations spread all over 300-500km
[20:51] <Tiger^> that's right.
[20:51] <HenryHallam> just balloon-to-ground would be ok though
[20:52] <Tiger^> hmm
[20:52] <macfreak4> thats what i'm doing
[20:52] <Tiger^> what about the cutdown command?
[20:52] <macfreak4> one-way rf communication
[20:52] <HenryHallam> we're not having a cutdown on Nova 1
[20:52] <Tiger^> pretty damn risky.
[20:52] <macfreak4> why?
[20:53] <HenryHallam> just assuming the balloon is going to pop before it gets over the sea
[20:53] <Tiger^> what if it drifts to the sea?
[20:53] <HenryHallam> maybe we ought to have one
[20:53] <Tiger^> or lands on a city hall? :)
[20:53] <HenryHallam> but if we it should be possible to design some conditions into the onboard computer to cutdown if it drifts outside of a certain position-altitude-velocity profile
[20:53] <Tiger^> you know what? a US group once had *three* *subsequent* permanent floaters
[20:53] <Tiger^> and they didn't have a cutdown device
[20:54] <Tiger^> you can imagine how bad they felt :)
[20:54] <HenryHallam> permanent floater? you mean the balloon didn't pop?
[20:54] <Tiger^> that's right
[20:54] <Tiger^> nobody knows why
[20:54] <HenryHallam> interesting
[20:54] <Tiger^> it just happens sometimes
[20:54] <Tiger^> it becomes naturally buoyant
[20:54] <macfreak4> neutrally?
[20:54] <HenryHallam> I will suggest a cutdown then
[20:54] <Tiger^> sorry
[20:54] <Tiger^> neutrally :)
[20:55] <macfreak4> o ok
[20:55] <Tiger^> HenryHallam: do that
[20:55] <jcoxon> hey all
[20:55] <HenryHallam> hi James
[20:55] <Tiger^> i'm launching from remote countryside
[20:55] <Tiger^> welcome back, jcoxon.
[20:56] <Tiger^> but there are towns in 60-70km radius
[20:56] <macfreak4> hey
[20:56] <Tiger^> and i'm imagining my balloon landing on a high building
[20:56] <Tiger^> or on a street with heavy traffic
[20:57] <jcoxon> Tiger^, how is your payload descending?
[20:57] <Tiger^> jcoxon: i'm going for a parachute from Rocketman Enterprises
[20:58] <jcoxon> i don't understand how you are going to avoid towns with a cutdown device
[20:58] <jcoxon> from say 20km up you are going to get up to 15km drift
[20:59] <jcoxon> depending on winds
[20:59] <Tiger^> yeah, that can happen
[20:59] <HenryHallam> I suppose you could predict the drift to a reasonable accuracy though
[20:59] <jcoxon> i agree a cutdown is important for the sea
[20:59] <Tiger^> i can't completely rule out the town landing possibility
[20:59] <jcoxon> no
[20:59] <HenryHallam> you could have a computer program display the current position and predicted position if cutdown now
[20:59] <jcoxon> i agree
[20:59] <Tiger^> HenryHallam: that's right
[21:00] <jcoxon> true
[21:00] <macfreak4> you could track it by car and be there when it lands too
[21:00] <macfreak4> ;)
[21:00] <Tiger^> if the flight path will seem to end in a town
[21:00] <Tiger^> then i'll decide whether to terminate the flight
[21:00] Action: jcoxon wants to catch a payload
[21:00] <HenryHallam> what and try to catch it ;)
[21:00] <HenryHallam> hehe
[21:00] <macfreak4> not nessesarily
[21:00] <jcoxon> i'd be interested to see how the cutdown goes
[21:00] <macfreak4> just be close so ppl dont get to it b4 you do
[21:00] <jcoxon> i haven't used one before
[21:00] <Tiger^> oh, i've already tried it
[21:00] <jcoxon> due to the lack on 2 way communication
[21:01] <Tiger^> on the ground, of course ;)
[21:01] <jcoxon> actually the lack of communication
[21:01] <Tiger^> a nichrome wire driven by a power MOSFET
[21:01] <HenryHallam> do you use a separate battery for that?
[21:01] <Tiger^> yup, i don't want to risk loss of GPS and telemetry
[21:02] <Tiger^> it'd be a shame if the cutdown worked fine but drained the batts completely :)
[21:02] <HenryHallam> right
[21:03] <HenryHallam> at the least I'd expect the battery voltage to dip a lot when melting
[21:03] <Tiger^> right, and that means flight computer brownout and reset
[21:04] <Tiger^> the pin for controlling the mosfet would be brought low then
[21:04] <Tiger^> and voltage would come back soon enough, but... better safe than sorry.
[21:04] <HenryHallam> yeah
[21:05] <HenryHallam> try to have the computer cope with a reset anyway
[21:05] <Tiger^> that's a must
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[21:06] <HenryHallam> Hi XJ
[21:06] <jcoxon> hey G0WXJ
[21:06] <G0WXJ> Hi James
[21:06] <jcoxon> hey pete
[21:06] <G0WXJ> what alot of faffing about
[21:06] <G0WXJ> got here in the end though
[21:06] <jcoxon> i think this might be a record amount of people on the channel
[21:06] <jcoxon> hehe
[21:06] <jcoxon> did you follow my guide?
[21:06] <G0WXJ> yup
[21:07] <jcoxon> cool
[21:07] <G0WXJ> very good...got me here anyway
[21:07] <jcoxon> we are discussing cutdown devices
[21:07] <G0WXJ> i thought about remote control scissors
[21:07] <jcoxon> perhaps introductions are required
[21:08] <G0WXJ> i think so yes#
[21:08] <jcoxon> HenryHallam is working with me on Nova (cambridge)
[21:08] <jcoxon> Tiger^ is launching in a month from poland
[21:08] <G0WXJ> Hi Henry
[21:08] <jcoxon> macfreak4 is in the USA and is launching soon
[21:08] <G0WXJ> A launcher, hi there
[21:08] <jcoxon> G0WXJ is in charge of Project SOAR
[21:09] <Tiger^> hi, G0WXJ
[21:09] <G0WXJ> I wouldn't say in charge
[21:09] <jcoxon> okay, well my contact
[21:09] <G0WXJ> I sometimes feel like the only one though :-)
[21:09] <HenryHallam> ah
[21:09] <Tiger^> oh, i've read about SOAR
[21:09] <HenryHallam> you're the guys trying to get us radio permission!
[21:09] <G0WXJ> thats the badger
[21:09] <jcoxon> :-)
[21:10] <Tiger^> you've got a Polish counterpart here
[21:10] <G0WXJ> Still waiting around for those lovey people to remove the finger
[21:10] <Tiger^> Project Copernicus
[21:10] <macfreak4> o hey
[21:10] <G0WXJ> Ah Tiger... nice to meet you, been keeping my eye on you guys
[21:10] <Tiger^> oh, i'm not with them :)
[21:11] <G0WXJ> I see
[21:11] <Tiger^> but i heard about them... they launch on the 3rd of June
[21:11] <G0WXJ> yes, thats right they do
[21:11] <Tiger^> and they've got their permission
[21:11] <Tiger^> call SR0FLY :)
[21:11] <G0WXJ> think they still have some final touches though
[21:11] <HenryHallam> XJ, do you know if there would be any legal issues with using a PMR radio and text-to-speech?
[21:12] <G0WXJ> depends which PMR
[21:12] <G0WXJ> text to speec h is fine on most comms though
[21:12] <G0WXJ> I use it on mmy echolink node
[21:13] <G0WXJ> license free pmr is even more restricted than Amateur radio
[21:13] <HenryHallam> the "no unmanned stations" applies to that as well then? :(
[21:13] <G0WXJ> The biggest problem over here are the frequencies that pmr operates, not the way they are operated
[21:14] <Tiger^> but there's no reg forbidding to send FSK through PMR :)
[21:14] <G0WXJ> not looked too deeply into all of th epmr, but there are normally restrictions for anattended op's
[21:14] <Tiger^> or is there?
[21:14] <HenryHallam> I read something saying it was for voice only
[21:15] <G0WXJ> data is fine normally, but as i say, not all pmr frequencies are multimode
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[21:15] <Tiger^> HenryHallam: you could whistle the marks and spaces yourself ;)
[21:15] <G0WXJ> many are voice only, but there are quite a few trunked radio systems popping up
[21:15] <Tiger^> that wouldn't be against the rules now would it? ;)
[21:15] <HenryHallam> http://www.ofcom.org.uk/static/archive/ra/publication/ra_info/ra357.htm this mentions speech only but doesn't say anything about unmanned
[21:16] <jcoxon> well i could quite easily output from my gumstix speech synthised gps coordinates
[21:16] <HenryHallam> Tiger, speech recognition software is quite good these days anyway
[21:16] <G0WXJ> checking
[21:17] <Tiger^> even better
[21:17] <Tiger^> you can use DTMF
[21:17] <Tiger^> or CTCSS codes
[21:17] <Tiger^> that's sooo allowed on PMR :)
[21:17] <G0WXJ> heres the killer though
[21:17] <G0WXJ> The accessories must be connected by appropriate sockets installed by the manufacturer at the time of manufacture and conformance evaluation and their use must not affect the RF characteristics of the radios
[21:18] <HenryHallam> that's ok
[21:18] <HenryHallam> because they have headset sockets
[21:18] <Tiger^> that's right
[21:18] <G0WXJ> note the...by the manufacturer
[21:18] <HenryHallam> yeah, the sockets were installed by the manufacturer
[21:18] <Tiger^> HenryHallam: no, no
[21:18] <HenryHallam> doesn't mention the plugs
[21:18] <Tiger^> HenryHallam: it's about antennae
[21:18] <G0WXJ> what about antenna
[21:18] <Tiger^> it's what i told you before
[21:18] <Tiger^> the trx/antenna *set* has a homologation
[21:18] <HenryHallam> antennae aren't included on the list of accessories you can plug in, whether sockets are provided or not
[21:19] <Tiger^> not the trx itself :)
[21:19] <G0WXJ> there may be an issue with deviation too, especially with some data stuff
[21:19] <HenryHallam> what do you mean by deviation?
[21:19] <Tiger^> frequency deviation
[21:19] <G0WXJ> the audio bandwidth
[21:19] <Tiger^> caused by the modulation signal
[21:19] <Tiger^> i wouldn't worry about that, though
[21:20] <G0WXJ> remember the bit about not affecting the RF characteristics
[21:20] <Tiger^> FSK has 1200Hz mark and 2200Hz space
[21:20] <G0WXJ> true
[21:20] <G0WXJ> to be honest...OFCOM couldn't police it anyway
[21:20] <jcoxon> but
[21:20] <jcoxon> we need to be transparent and legal
[21:20] <G0WXJ> the only down side to any launch is it has to remain secret
[21:20] <jcoxon> :(
[21:20] <HenryHallam> we're trying to do things on the straight and narrow to look good to sponsors
[21:21] <G0WXJ> i agree
[21:21] <Tiger^> so tell them you used the ISM band
[21:21] <G0WXJ> thats why we are trying to get these stupid 50 year old rules changed
[21:21] <Tiger^> and QRP (low power) trxes
[21:21] <jcoxon> i still thinking packet modems
[21:21] <G0WXJ> the picobeacon is a little corker to be honest
[21:22] <G0WXJ> I have also been looking at some of the radio directionfinding kit too
[21:23] <G0WXJ> I have a little 500 milliwatt tx sat here now, it's tiny
[21:23] <Tiger^> 500mW is too much for them
[21:24] <jcoxon> picobeacons are the ultimate though
[21:24] <Tiger^> permission issues...
[21:24] <G0WXJ> I have been attempting to reduce this
[21:24] <jcoxon> gps, flight computer, logging, landing prediction
[21:24] <G0WXJ> I think i can get down to around 50 milliwatts
[21:24] <jcoxon> on 2 AAs
[21:25] <HenryHallam> nice
[21:25] <G0WXJ> I think our kit will need a little more than 2 AA's :-)
[21:25] <HenryHallam> heh
[21:27] <HenryHallam> http://cgi.ebay.co.uk/Set-of-2-Kenwood-TK-3207-handheld-PMR-446-High-Power-5W_W0QQitemZ9717447094QQcategoryZ72405QQrdZ1QQcmdZViewItem
[21:27] <HenryHallam> plausible deniability, "oops we didn't realise it was set to 5W"
[21:27] <jcoxon> how about our radio modem
[21:27] <jcoxon> oops its at 35W
[21:28] <Tiger^> but you don't really need 5W
[21:28] <G0WXJ> at least the american could take part then
[21:28] <Tiger^> haha ;)
[21:28] <HenryHallam> with those small antennae we do need a bit of power though don't we?
[21:28] <Tiger^> with those rubber duckies 10W wouldn't do.
[21:28] <G0WXJ> I have been looking at HF frequencies too, they do this in NL at the moment
[21:29] <jcoxon> i know this is a bit rubbish but HenryHallam :
[21:29] <jcoxon> http://traxa.co.uk/uk.html
[21:29] <Tiger^> you *have* to have a higher gain antenna
[21:29] <Tiger^> maybe use a j-pole?
[21:30] <G0WXJ> interesting frequencies
[21:30] <Tiger^> it'll look like a string hanging from the payload
[21:30] <G0WXJ> have a google for coaxial colinear antenna
[21:30] <HenryHallam> james, that traxa is what I was working out for doing an aerial search
[21:30] <G0WXJ> 5-7 dBd gain
[21:31] <Tiger^> yeah, it's nice
[21:31] <Tiger^> but haven't used it.
[21:31] <jcoxon> okay
[21:31] <G0WXJ> then yagi at RX site with 9-12 dBd gain, sorted !
[21:31] <jcoxon> they claim up to 31,000ft
[21:32] <HenryHallam> XJ, sounds good
[21:32] <HenryHallam> but not legal for us
[21:32] <G0WXJ> I have tested line of site on the radiometrix stuff and acheived about 1.5Km on the ground with nothing special for an antenna
[21:33] <Tiger^> HenryHallam: and that's why i'd go for a j-pole
[21:33] <jcoxon> so really the final distance to retriving the payload
[21:33] <Tiger^> it really looks like a loose string, if made correctly
[21:33] <Tiger^> and on the receiving side, all you need is a mag-mount omni
[21:33] <HenryHallam> nice :)
[21:33] <G0WXJ> is that the one made from 300ohm ribbon feeder?
[21:34] <Tiger^> G0WXJ: that's the one
[21:34] <G0WXJ> they work extremely well, in fact there are some on ebay I think
[21:34] <Tiger^> hmm
[21:34] <Tiger^> it's so easy to make i wouldn't buy it
[21:34] <G0WXJ> you may find them under SOTA antennas
[21:35] <Tiger^> i'd make one myself :)
[21:35] <HenryHallam> I definitely think we should carry a traxa, and if we don't get a phone signal after a few hours then we fly a search pattern in the general direction the winds blew / over the same area where Pegasus landed
[21:35] <G0WXJ> I should think so too
[21:35] <G0WXJ> You can use pmr 446 when it's on the ground
[21:36] <G0WXJ> now there is a thought
[21:36] <Tiger^> hmm
[21:36] <HenryHallam> between search party members do you mean? or for location
[21:36] <jcoxon> HenryHallam, we of course will have my secondary payload
[21:36] <jcoxon> hehe
[21:37] <HenryHallam> right
[21:37] <Tiger^> in Poland, you can use PMR446 in mid-air
[21:37] <G0WXJ> If I jumped up and down with a walkie talkie, would that mean I was 50% aeronautical mobile and so breaking the law?
[21:37] <HenryHallam> hahaha
[21:37] <Tiger^> glider pilots use them for comm
[21:37] <HenryHallam> I haven't seen anything saying you can't use PMR446 licence free for aero stuff though, where does it say that?
[21:37] <G0WXJ> luck beggars
[21:37] <Tiger^> yup.
[21:37] <G0WXJ> different authority over there
[21:38] <G0WXJ> so....about this cut down device
[21:38] <jcoxon> well we can go for a radio controlled cutdown device
[21:38] <jcoxon> so it'll have to be preprogrammed
[21:39] <G0WXJ> yep, how about pressure switch operated
[21:39] <HenryHallam> I was going to suggest a fixed 2 hour timer
[21:39] <Tiger^> pressure switch? what for?
[21:39] <G0WXJ> when you reach a desired flight level
[21:39] <Tiger^> ah, that's another problem
[21:40] <jcoxon> i'm thinking match location with a set of gps coordinates
[21:40] <Tiger^> you can't use a pressure sensor for your balloon
[21:40] <jcoxon> and cutdown when straying out of them
[21:40] <Tiger^> HenryHallam: fixed timer + distance limit
[21:40] <G0WXJ> there are 2 requirements though
[21:40] <Tiger^> neither one by itself is not good enough
[21:40] <G0WXJ> forced cut down
[21:40] <G0WXJ> and controlled cut down
[21:41] <HenryHallam> ah
[21:41] <HenryHallam> PMR446 is illegal for aero use
[21:41] <HenryHallam> BUT
[21:41] <HenryHallam> this is CAA rules
[21:41] <Tiger^> oh
[21:41] <G0WXJ> forced cut down in case one fails or you go beyond parammeters
[21:41] <HenryHallam> so it applies to pilots (including gliders and hot air balloonists)
[21:41] <HenryHallam> but not to unmanned balloons
[21:41] <G0WXJ> OFCOM are currently looking at mobile use in aircraft, so won't be long
[21:42] <Tiger^> you can have one thing for sure
[21:42] <HenryHallam> the restriction is not in the OFCOM regulations as far as I can tell, it's in the Air Nav Order
[21:42] <Tiger^> a *receiver* on board and a transmitter on the ground
[21:42] <G0WXJ> it is the CAA that are holding everything up
[21:42] <Tiger^> so at least the cutdown problem can be dealt with
[21:42] <G0WXJ> OFCOM can't move until CAA give it the thumbs up
[21:43] <jcoxon> lets get in there now then :-p
[21:43] <G0WXJ> I like the look of the servo operated ones
[21:43] <G0WXJ> simple pin and ring arrangement
[21:44] <HenryHallam> it doesn't really solve the commanded cutdown issue because we can't use external antennae and you guys think the built in ones wouldn't have the range?
[21:44] <G0WXJ> and for backup, go for the melted string effect
[21:44] <HenryHallam> http://www.446user.co.uk/forum_topic_562.html this is encouraging though w.r.t. range
[21:44] <G0WXJ> doesn't stop you from inductively coupling the antenna though
[21:44] <Tiger^> HenryHallam: no, you can use whatever you want for a receiver
[21:45] <HenryHallam> oh ok
[21:45] <Tiger^> you can even make one yourself
[21:45] <Tiger^> all the regs apply to transmitters or transceivers
[21:46] <HenryHallam> so can you hook a homemade big ass antenna up to a commercial transceiver but use it only to receive?
[21:46] <Tiger^> nope
[21:46] <G0WXJ> yep, its the transmission thats not allowed
[21:46] <macfreak4> release at high altitude?
[21:46] <Tiger^> but you can buy a $1000 scanner and attach a homemade big ass antenna to it
[21:46] <G0WXJ> you can modify it as much as you like, you just cannot tx on it
[21:46] <Tiger^> G0WXJ: are you sure?
[21:47] <G0WXJ> yep
[21:47] yourmom (n=klkj@adsl-75-6-242-126.dsl.pltn13.sbcglobal.net) joined #highaltitude.
[21:47] <Tiger^> so it's different in the UK.
[21:47] Nick change: yourmom -> mongrethod
[21:47] <jcoxon> hey yourmom, interesting name
[21:47] <G0WXJ> the wireless telegraphy act is for transmission in this case anyway
[21:47] <HenryHallam> Hi Susan
[21:47] <mongrethod> That's what you get for allowing stupid little brothers on IRC :(
[21:47] <Tiger^> in poland you're not supposed to even possess a TRX you're not allowed to use
[21:48] <mongrethod> I have a question about using GPS with Gumstix waysmall's, anyone have any experience with that?
[21:48] <G0WXJ> same here in some cases, but that is for police frequencies etc, not public use frequencies
[21:48] <jcoxon> yup
[21:49] <jcoxon> what the issue?
[21:49] <mongrethod> well, two things
[21:49] <jcoxon> what gps are you using?
[21:49] <mongrethod> first off did you use the packaged one they sell?
[21:49] <mongrethod> "
[21:49] <mongrethod> *"Gpstix" i believe its called
[21:49] <jcoxon> i have one right now
[21:49] <mongrethod> oh ok nice
[21:49] Action: jcoxon wasthe first to get one
[21:49] <jcoxon> was*
[21:49] <mongrethod> have you had any problems, or would you reccomend it
[21:49] <jcoxon> but i have also used cf gps
[21:49] <jcoxon> and serial gps with gumstix
[21:49] <jcoxon> s
[21:50] <Tiger^> G0WXJ, here you can only have CBs, mobiles, cordless phones, wireless headphones, wifi... and that's probably it.
[21:50] <jcoxon> well i haven't really tested it as i don't have an aerial yet
[21:50] <jcoxon> though it is 16 channels so its a good one
[21:50] <G0WXJ> really.....
[21:50] <jcoxon> and works immediatly
[21:50] <mongrethod> so i've been using linux for about 5 years in a server environment, but I haven't played around with anything else
[21:50] <mongrethod> works immediately
[21:50] <mongrethod> as in you plug it in
[21:51] <mongrethod> and you get NMEA output?
[21:51] <jcoxon> for the gpsstix its a matter of cat /dev/ttyS2
[21:51] <mongrethod> oh wow
[21:51] <Tiger^> G0WXJ: if it transmits on a license-only band, you have to have that license.
[21:51] Action: mongrethod is in love
[21:51] <G0WXJ> thats why I'm here....I have no idea about any of the gumstix/linux stuff
[21:51] <jcoxon> perhaps stty -F /dev/ttyS2 speed 9600
[21:51] Action: mongrethod 's love is not hampered by stty
[21:51] <mongrethod> that's really sweet.
[21:51] <jcoxon> when i get my cable back for my camera i'll take some pictures
[21:51] <mongrethod> They are sold out right now though T_T
[21:51] <jcoxon> wow
[21:51] <mongrethod> yeah
[21:51] <jcoxon> didn't know that
[21:51] <jcoxon> they are good
[21:52] Action: jcoxon is loving his free board
[21:52] <jcoxon> hehe
[21:52] <mongrethod> wtf?
[21:52] <mongrethod> how'd you get it free
[21:52] <mongrethod> :O
[21:52] Action: jcoxon is spwecial
[21:52] Action: mongrethod crys
[21:52] <mongrethod> that's sweet though
[21:52] <jcoxon> its my 3rd gumstix
[21:52] <mongrethod> is there a particular waysmall I need to buy to use it?
[21:52] <jcoxon> nope
[21:53] <mongrethod> sweet
[21:53] <G0WXJ> BRB
[21:53] <mongrethod> oh yeah, i was wondering, what flavor of linux do the gumstix comps run?
[21:53] <jcoxon> its own
[21:53] <jcoxon> uclibc
[21:53] <mongrethod> care to make a comparison to a more well known distro, or is it really different
[21:53] <mongrethod> i imagine it's just really stripped down?
[21:54] <HenryHallam> how much flash does the gumstix have btw?
[21:54] <mongrethod> IIRC up to 512mb expandable?
[21:55] <jcoxon> umm well its embedded linux
[21:55] <jcoxon> so its not like fedora or debian
[21:55] <jcoxon> simple command line
[21:55] <jcoxon> actually its only got 16mb of flash
[21:55] <jcoxon> but either with an mmc card or cf card you can expand it
[21:56] <jcoxon> i got by with the old version with 4mb of flash
[21:56] <mongrethod> heh, im spoiled on debian with XGL
[21:56] <jcoxon> mongrethod, what you planning to use it for
[21:56] <jcoxon> ?
[21:56] <jcoxon> well you ain't going to get X!
[21:56] <mongrethod> lol i know
[21:56] <mongrethod> :P
[21:56] <mongrethod> "yeah my gumstix is running XGL, 3d rendering my desktop as we speak"
[21:57] <mongrethod> so the project
[21:57] <mongrethod> is a device that uploads its position via GPS and wifi to a server where it gets posted to the web
[21:57] <jcoxon> to track what?
[21:57] <jcoxon> :-)
[21:57] <mongrethod> ok, this takes some explanation
[21:57] <jcoxon> hehe
[21:58] <mongrethod> basically, im making something that can be abandoned somewhere, and will then instruct anyone who picks it up to take it as far as they can in X direction, then pass it off to someone else
[21:58] <mongrethod> it kinda depends on strangers not being jerks, but we'll see how it goes
[21:58] <jcoxon> ooo interesting idea
[21:58] <mongrethod> :-)
[21:58] <jcoxon> so it'll log on to any wifi and upload?
[21:58] <mongrethod> yep
[21:59] <mongrethod> still working out the best way to do that
[21:59] <mongrethod> also its kinda annoying to make this all secure in PHP
[21:59] <jcoxon> so you need a gpstix + gumstix connex 200 and cfstix with cf wireless
[21:59] <mongrethod> ooh, thanks :)
[21:59] <jcoxon> or wait for the wifi daughter card to come out
[21:59] <mongrethod> wifi daughter card?
[21:59] <HenryHallam> put lots of stickers on it explaining how it's "armless"
[21:59] <mongrethod> armless?
[21:59] <jcoxon> yeah they are making on
[21:59] <mongrethod> hurr?
[21:59] <jcoxon> oi
[22:00] <jcoxon> long story
[22:00] <mongrethod> do tell
[22:00] <jcoxon> carl's fault
[22:00] <Tiger^> too much duct tape? :)
[22:00] <jcoxon> well my last launch the payload had a not on it saying harmless
[22:00] <jcoxon> and there was to much duct tape...
[22:01] <jcoxon> mongrethod, i've got a better idea :-D
[22:01] <jcoxon> firstly you are in the right channel for remote tracking
[22:01] <mongrethod> :)
[22:01] <jcoxon> stuff the wireless
[22:01] <jcoxon> use gsm
[22:01] <jcoxon> every day have it upload its position thorough a gsm module from spark fun
[22:02] <mongrethod> oooooh XD
[22:02] <mongrethod> that's coooool
[22:02] <jcoxon> pretty much always get reception
[22:02] <mongrethod> and much less dependent on NOT being in the middle of the midwest without wifi
[22:02] <jcoxon> exactly
[22:02] <jcoxon> either sms or actually dial up with ppp
[22:02] <jcoxon> i've done both
[22:02] <mongrethod> hmm
[22:02] <jcoxon> okay it'll cost
[22:03] <jcoxon> but stick some pay as you go credit on it and if one message is sent per day that'll last
[22:03] <jcoxon> and you can remotly add more
[22:04] <jcoxon> its sort of like the geocaches that people send objects around hte work
[22:04] <jcoxon> world*
[22:04] <jcoxon> just slightly more hightech
[22:04] <mongrethod> heh, yeah
[22:04] <mongrethod> im going to include a camera
[22:04] <mongrethod> such that people can take pics
[22:05] <mongrethod> and it will store (or maybe upload) them
[22:05] <jcoxon> at the moment there isn't usb
[22:05] <jcoxon> so it would have to go over serial i guess
[22:05] <mongrethod> there are converters no?
[22:05] <macfreak4> no
[22:05] <jcoxon> wrong direction
[22:06] <G0WXJ> back now
[22:06] <mongrethod> oh,.
[22:06] <mongrethod> hmm
[22:06] <HenryHallam> how about a CF USB card?
[22:06] <HenryHallam> do those exist?
[22:06] <jcoxon> yeah its possible
[22:06] <jcoxon> yup
[22:06] <jcoxon> and with linux drivers
[22:06] <jcoxon> but i'm not sure anyone has actually got one working
[22:06] <jcoxon> people have tried
[22:06] <jcoxon> you'd have to try the gumstix mailing list
[22:06] <mongrethod> hehh
[22:07] <mongrethod> im so glad I came to this channel though
[22:07] <mongrethod> or i'd have done alot of things wrong
[22:07] <macfreak4> umm idea...
[22:07] <mongrethod> and wasted alot of time/money
[22:07] <jcoxon> hehe
[22:07] <HenryHallam> ordinary digital camera with a CF card and a little mechanical robot to unplug the card and plug it into the gumstix
[22:07] <mongrethod> LOL
[22:07] <macfreak4> the old nikon coolpixes
[22:07] <macfreak4> used serial for data xfer
[22:07] <mongrethod> instead of a mechanical "robot" a large relay array'd work
[22:07] <jcoxon> yeah
[22:07] <mongrethod> oh really?
[22:07] <mongrethod> that's nice
[22:08] <macfreak4> sry i hav 2 type w 1 hand
[22:08] <mongrethod> I think i might actually HAVE one of those somewhere too
[22:08] <HenryHallam> I dunno I like the robot idea better ;)
[22:08] <mongrethod> lol
[22:08] <macfreak4> but they can be fully controlled over serial too
[22:08] <macfreak4> i had a url as i was going to use a pic and by old coolpix 800 on my balloon
[22:09] <macfreak4> but i'm using a webcam now so...
[22:09] <G0WXJ> I ripped the guts out of a Cocord eyeQ today...its tiny
[22:09] <macfreak4> serial is slow no doubt but 4 your purposes it might work
[22:10] <mongrethod> i dont want video or anything
[22:10] <HenryHallam> probably faster than the GSM
[22:10] <mongrethod> lol
[22:10] <macfreak4> the old coolpix 800 i have is 2mp
[22:10] <mongrethod> just still pics
[22:10] <mongrethod> so speed shouldnt be an issue
[22:10] <macfreak4> ya
[22:10] <jcoxon> there are also i2c cameras
[22:10] <macfreak4> lower res tho probably
[22:10] <jcoxon> true
[22:11] <mongrethod> so im thinking charging wise, it can just ask to be charged by the people who transport it
[22:11] <mongrethod> i.e. "plug me in please :O"
[22:11] <macfreak4> solar :P
[22:11] <mongrethod> no way
[22:11] <macfreak4> ya
[22:11] <mongrethod> too big
[22:11] <mongrethod> wayyy too big
[22:11] <macfreak4> the gumstix uses almost no pwr at all
[22:11] <mongrethod> just asking to be charged is much better
[22:11] <macfreak4> not really too big
[22:11] <mongrethod> gumstix+camera+gps
[22:11] <mongrethod> +GMS
[22:11] <mongrethod> +some other shit i might tack on
[22:11] <mongrethod> = lots of power
[22:11] <HenryHallam> yeah you'd need a big panel for all that
[22:11] <macfreak4> yes but the gms is periodic
[22:12] <macfreak4> and the camera is periodic
[22:12] <mongrethod> true
[22:12] <macfreak4> and the gumstix is on the order of a few ma
[22:12] <mongrethod> the GPS could actually be semi-periodic also
[22:12] <macfreak4> so you could possibly use small solar cells and make a simple charging circuit
[22:12] <macfreak4> i duno w/e u want to do
[22:12] <G0WXJ> I have seem some thin PV film somewher I'm certain
[22:12] <HenryHallam> provide a whole bunch of different sockets on the back and a universal regulator so they can plug any wall-wart in
[22:13] <mongrethod> thats a good idea henry
[22:13] <jcoxon> or have easily changed batteries
[22:13] <macfreak4> haha nice
[22:13] <mongrethod> i was thinking also a car ciggarette adapter
[22:13] <jcoxon> say 3AA
[22:13] <jcoxon> or AAAs
[22:13] <mongrethod> yeah
[22:13] <mongrethod> that'd be good too
[22:13] <jcoxon> perhaps monitor charge some how and have a flashing light when going to run down
[22:13] <mongrethod> I have a colo'd server with a dual t3 connection, so im hoping to attract transporters with webspace
[22:14] <macfreak4> lol
[22:14] <mongrethod> such that they can take pics
[22:14] <macfreak4> bribery
[22:14] <mongrethod> and they will be on the site
[22:14] <mongrethod> :)
[22:14] <HenryHallam> I'm not sure people would want to pay for new batteries for the thing
[22:14] <mongrethod> i dno, other geeks?
[22:14] <jcoxon> i tihnk in the spirit of the thing
[22:14] <mongrethod> i'd sure as hell do it myself if it was someone elses project
[22:14] <jcoxon> look at the guy swapping a paper clip for a house
[22:14] <HenryHallam> heh, true
[22:15] <macfreak4> yes but taking batteries out to replace them would turn off the gunstix and might render unfavourable results
[22:15] <jcoxon> its pretty stable
[22:15] <jcoxon> you can't shut it down :-p
[22:15] <jcoxon> basically mongrethod use my design on my website
[22:15] <mongrethod> o.o
[22:15] <HenryHallam> I think wall warts + cigarette lighter + USB would be good
[22:15] <Tiger^> the software should be reset-proof :)
[22:15] <HenryHallam> you can take power from USB without worrying about the data side
[22:15] <jcoxon> but instead of launching it
[22:15] <jcoxon> leave it somewhere
[22:15] <mongrethod> you could make a "mini-UPS" with a battery that only kicks in when the others are removed
[22:16] <macfreak4> sure that might do it
[22:16] <jcoxon> and it sends a message saying "aaaarrgghhh i'm dieing
[22:16] <mongrethod> I'm a junior in HS, but I work at stanford, so I have access to a bunch of machinelab stuff
[22:16] <jcoxon> here are my last coordinates"
[22:16] <mongrethod> so i can fab some nice things
[22:16] <jcoxon> so you can find it
[22:16] <mongrethod> hahaha
[22:16] <mongrethod> that'd be sweet
[22:16] <mongrethod> i was thinking of ways to deter malicious people from fucking it up
[22:16] <mongrethod> any thoughts?
[22:16] <mongrethod> it cant be anything violent obviously
[22:17] <jcoxon> apart from a really solid case and have it so nothing else can be don with it
[22:17] <jcoxon> you'll just have to trust people
[22:17] <jcoxon> and actually people will pass it on to people they think will treat it properly
[22:17] <G0WXJ> how about needles that come out of th ecase if tampered with
[22:17] <Tiger^> skunk fluid!
[22:17] <jcoxon> it explodes!
[22:17] <Tiger^> dripping out of the case upon opening!
[22:17] <Tiger^> ;)
[22:18] <macfreak4> tear gas
[22:18] <macfreak4> haha
[22:18] <HenryHallam> one of those camera flash charger circuits
[22:18] <Tiger^> oh yes!
[22:18] <G0WXJ> oh yeah...they hurt
[22:18] <Tiger^> the flash chargers really hurt
[22:18] <Tiger^> :)
[22:18] <mongrethod> 'NOTHING VIOLENT'
[22:18] <mongrethod> :P
[22:18] <mongrethod> i'd love to have it transform into a camera charger shooting optimus prime
[22:18] <jcoxon> they shouldn't of tried to open it
[22:18] <Tiger^> mongrethod: flash capacitors aren't violent
[22:18] <HenryHallam> yeah we had a month-long war with those things at my high school one year
[22:18] <G0WXJ> just a little flash circuit then
[22:18] <Tiger^> they're just painful
[22:18] <Tiger^> ;)
[22:18] <mongrethod> haha
[22:19] <mongrethod> i made a taser out of one of those at camp
[22:19] <mongrethod> just the cap, on a stick, with long wires
[22:19] <jcoxon> well a gps stix has audio out
[22:19] <mongrethod> we used to hike in lines
[22:19] <mongrethod> so...
[22:19] <jcoxon> ooooo
[22:19] <mongrethod> bzap!
[22:19] <jcoxon> audio in
[22:19] <mongrethod> audio!
[22:19] <mongrethod> nice
[22:19] <mongrethod> "STOP STEALING ME!!!"
[22:19] <jcoxon> + microphone
[22:19] <mongrethod> or what if it just yelled
[22:19] <jcoxon> they can record messages
[22:19] <mongrethod> "RAPE!!"
[22:19] <mongrethod> that'd be cool
[22:19] <HenryHallam> "we know where you live and we just took a photo of you"
[22:19] <jcoxon> a really high pitched scream
[22:19] <mongrethod> induce them to drop it
[22:20] <jcoxon> it'll bounce
[22:20] <mongrethod> i'll have to make it really sturdy
[22:20] <jcoxon> gumstixs are tough
[22:20] <mongrethod> but i was gonna have to make it really sturdy anyway
[22:20] <G0WXJ> this box is being tracked, I know where we are
[22:20] <jcoxon> i've dropped one from 66,000ft
[22:20] <mongrethod> !!!
[22:20] <jcoxon> okay with a parachute but still
[22:20] <mongrethod> hahahahaah
[22:20] <macfreak4> i g2g
[22:20] <macfreak4> got a paper 2 write...
[22:20] <macfreak4> :(
[22:20] <G0WXJ> talking of parachutes.......
[22:20] <macfreak4> cya
[22:20] <mongrethod> later
[22:21] <mongrethod> thanks for the help
[22:21] macfreak4 (n=macfreak@24-107-201-22.dhcp.stls.mo.charter.com) left irc:
[22:21] <mongrethod> :)
[22:21] <G0WXJ> I have been thinking about those sycamore seeds
[22:21] <jcoxon> i've never seen this channel so active
[22:21] <mongrethod> haha
[22:21] <mongrethod> my idea, its just that cool
[22:21] <mongrethod> j/k ^_^
[22:21] <G0WXJ> instead of a chute, use a heli foil of some sort
[22:22] <jcoxon> nova 1 has a very cool parachute design
[22:22] <G0WXJ> may even be steerable too?
[22:22] <jcoxon> parafoils are being researched presently by defy in NZ
[22:22] <HenryHallam> hm, that would be cool.. if it thinks it's drifting over the sea, it cuts down and tries to glide towards land
[22:23] <jcoxon> http://defy.net/balloon/
[22:23] <mongrethod> So you guys are all in the UK?
[22:23] <HenryHallam> james, I posted on the board about needing a cutdown
[22:23] <G0WXJ> seen those, they tangle during freefall though don't they
[22:23] <HenryHallam> james and I are
[22:23] <jcoxon> henry, yeah a i saw
[22:23] <G0WXJ> me too
[22:23] <jcoxon> G0WXJ, yeah they do - not a fan
[22:23] <jcoxon> glider would be a better option
[22:23] <jcoxon> mongrethod, its sort of uk based but others are here
[22:23] <jcoxon> macfreak is US
[22:23] <G0WXJ> yeah, future thought for me....just want to get off the ground
[22:23] <jcoxon> Tiger^ is from poland
[22:24] <jcoxon> malgar is italy
[22:24] <jcoxon> icez is USA
[22:24] <jcoxon> and zeusbot doesn't really say much
[22:24] <jcoxon> hehe
[22:25] <G0WXJ> anyway.....about the cutdown device
[22:25] <G0WXJ> where did you get to?
[22:25] Action: mongrethod is a junior in USA (california!)
[22:25] Action: mongrethod has to go finish calibrating his new 'scope ^__^, and is very happy to have found such helpful people
[22:26] <mongrethod> bye all
[22:26] <G0WXJ> bye now
[22:26] <HenryHallam> later
[22:26] <Tiger^> bye mongrethod, nice talking to you
[22:27] <HenryHallam> Either a hotwire or servo thing, its own battery, a 555 timer running on that battery but also signalable by the PIC if the predicted landing site leaves a certain envelope
[22:28] <G0WXJ> BTW James, where was the video taken for the Peg 1?
[22:28] <Tiger^> hotwire is prob'ly more reliable
[22:28] <G0WXJ> I fancy the hotwire as a backup device but not the main cutaway
[22:28] <jcoxon> its on youtube
[22:29] <Tiger^> i'm going for the NiCr wire as the primary cutdown
[22:29] <Tiger^> driven by a mosfet and controlled by AVR
[22:29] <G0WXJ> yeah JC i have seen it
[22:29] <G0WXJ> just wondered where you were taking off from
[22:29] <jcoxon> you mean where where as in location?
[22:29] <jcoxon> of home
[22:29] <jcoxon> so suffolk
[22:29] <jcoxon> peg II was cambridge
[22:30] <G0WXJ> nice garden to play balloons in then LOL
[22:30] <jcoxon> my parents...
[22:30] Action: Tiger^ hasn't seen it, 'cause someone tagged is as adult content, requiring login.
[22:30] <jcoxon> i'll untag it
[22:30] <jcoxon> well try
[22:30] <jcoxon> its also on google
[22:30] <jcoxon> search for pegasus and balloon
[22:31] <Tiger^> oh
[22:31] <Tiger^> right
[22:31] <Tiger^> i've got it
[22:31] <G0WXJ> I couldn't help but notice the cam operator got a little excited when it took off
[22:31] <jcoxon> hehe yeah she did
[22:31] mongrethod (n=klkj@adsl-75-6-242-126.dsl.pltn13.sbcglobal.net) left irc:
[22:31] <jcoxon> launches are exciting!
[22:31] <Tiger^> ;)
[22:31] <G0WXJ> had to turn the volume down twice LOL
[22:32] <G0WXJ> can you offer any advice to someone who has no idea what gumstix is?
[22:32] <jcoxon> yup
[22:32] <jcoxon> i've had 3
[22:32] <G0WXJ> or linus for that matter
[22:32] <jcoxon> linux
[22:32] <G0WXJ> linux that is
[22:32] <jcoxon> is an operating system
[22:32] <jcoxon> like windows
[22:33] <jcoxon> but is much more scalable
[22:33] <jcoxon> and free
[22:33] <G0WXJ> I know that bit
[22:33] <jcoxon> hehe
[22:33] <jcoxon> i'll stop patronising
[22:33] <G0WXJ> is it neede for gumstix
[22:33] <jcoxon> you can login via windows
[22:33] <jcoxon> via ssh
[22:33] <jcoxon> and usbnet
[22:33] <G0WXJ> ok
[22:33] <G0WXJ> any dummy guides to gumstix anywhere?
[22:33] <jcoxon> yup
[22:34] <G0WXJ> BTW, I have 10 pilot balloons heading my way if you need any
[22:34] <jcoxon> http://www.gumstix.org/tikiwiki/tiki-view_faq.php?faqId=11#q105
[22:35] <jcoxon> ooo cool
[22:35] <jcoxon> i've got 2x200gm and 1x500gm right now
[22:35] <G0WXJ> I am also in contact with a potential cheap supplier
[22:35] <jcoxon> hehe nova have sent me on a mission when i'm in africa this summer to get hold of some zero pressure balloons
[22:35] <jcoxon> 30000m3
[22:35] <jcoxon> hehe
[22:36] <G0WXJ> have you seen the French solar balloon?
[22:36] <jcoxon> which one?
[22:36] <jcoxon> CNES?
[22:36] <G0WXJ> not sure?
[22:36] <jcoxon> probably
[22:36] <G0WXJ> that looked interesting
[22:36] <G0WXJ> but restricted in payload I guess#
[22:37] <jcoxon> CNES are the french space agency
[22:37] <jcoxon> they are the experts at balloons
[22:37] <jcoxon> probably better then nasa
[22:37] <HenryHallam> ah
[22:38] <HenryHallam> are those the people you're working with in Africa?
[22:38] <jcoxon> ypu
[22:38] <jcoxon> yup*
[22:38] <G0WXJ> looking at that gumstix site now....still over my head....need dummy guide really
[22:38] <jcoxon> i'll explain
[22:38] <jcoxon> basically its a really small computer
[22:38] <jcoxon> running linux means it can run normal software
[22:39] <jcoxon> either 200mhz or 400mhz
[22:39] <jcoxon> and then a variety of daughter cards
[22:39] <jcoxon> so for example i have right now a cfstix which can take cf cards
[22:39] <jcoxon> gpstix which has a 16channel gps on it and lots of inputs and outputs
[22:40] <jcoxon> and these attach to the centre gumstix
[22:40] <HenryHallam> how many daughter cards can you have at a time?
[22:40] <jcoxon> 2
[22:40] <jcoxon> one on top and one on the bottom
[22:40] <jcoxon> thought some only go on top
[22:40] <jcoxon> e.g. the cfstix
[22:40] <jcoxon> and gpstix on the bottom
[22:41] <G0WXJ> and then you write linux bases S/W to run various things on the gumstix
[22:41] <jcoxon> yeah
[22:41] <jcoxon> well i didn't write any software
[22:41] <jcoxon> i used standard desktop software
[22:41] <jcoxon> so gpsd to read the gps
[22:41] <jcoxon> and gnokii to talk to the phone
[22:41] <G0WXJ> ok
[22:42] <G0WXJ> is there somewhere i can find this desktop software?
[22:42] <jcoxon> they are designed for desktops
[22:42] <jcoxon> oh yes
[22:42] <G0WXJ> more interested in the ham radio stuff really
[22:42] <jcoxon> well google linux and ham
[22:42] <jcoxon> there are loads of different free programs
[22:44] <G0WXJ> first hit...jobs a gun un......http://radio.linux.org.au/ aprs stuff.......
[22:45] <jcoxon> cool
[22:46] <G0WXJ> That's about it for me I think....need to go and inject some RF, not been near the radio today
[22:46] <jcoxon> hehe
[22:46] <HenryHallam> later
[22:46] <jcoxon> well glad you found the channel
[22:46] <G0WXJ> nice chatting James, I'll keep in touch
[22:46] <jcoxon> though its not usually this busy!
[22:47] <Tiger^> 73s, G0WXJ ;)
[22:47] <jcoxon> i'll keep you updated on progress
[22:47] <G0WXJ> fine with me....I feel like a sponge.....need as much info as I can get
[22:47] <G0WXJ> cheers guys
[22:47] <jcoxon> please do join up to http://ukhas.org.uk
[22:47] <jcoxon> http://www.ukhas.org.uk
[22:48] <G0WXJ> will do....
[22:48] G0WXJ (i=Pete@g0wxj.demon.co.uk) left irc: "Leaving"
[22:48] <Tiger^> jcoxon, btw, what whas the payload's weight on Pegasus I and II?
[22:49] <Tiger^> err, was
[22:49] <jcoxon> peg I was 1kg
[22:49] <jcoxon> peg II was about 1.5kg
[22:49] <jcoxon> peg III will be less then 1kg
[22:49] <Tiger^> and you're using 200/500g balloons, right?
[22:50] <jcoxon> peg III will be a 200gm
[22:50] <jcoxon> you need an extra lb of lift appox
[22:50] <jcoxon> approx*
[22:50] <Tiger^> and peg I was?
[22:50] <jcoxon> 0.45kg
[22:50] <jcoxon> peg I was a 200
[22:50] <jcoxon> peg II was a 1200
[22:50] <Tiger^> oh
[22:50] <jcoxon> :-p
[22:50] <Tiger^> i went for a 1500 ;)
[22:50] <jcoxon> payload weight?
[22:51] <Tiger^> balloon
[22:51] <jcoxon> yeah
[22:51] <Tiger^> payload will be about 1.5kg
[22:51] <jcoxon> okay
[22:51] <jcoxon> lucky you have a cutdown device
[22:51] <jcoxon> that'll go high!
[22:51] <Tiger^> yeah
[22:51] <jcoxon> even if you over fill it
[22:51] <Tiger^> i could make it less than 1.5kg
[22:51] <jcoxon> :-D
[22:51] <jcoxon> don't think you need to!
[22:52] <Tiger^> but my chute's minimum is 1.5 :)
[22:52] <jcoxon> right
[22:52] <Tiger^> and i don't want it to drift too much
[22:52] <jcoxon> no thats true
[22:52] <jcoxon> so many factors
[22:52] <Tiger^> i'm thinking about as much as 3lbs of lift
[22:53] <Tiger^> maybe that's stretching it
[22:53] <Tiger^> literally :))
[22:53] <Tiger^> but i want the flight path to be as vertical as it can get
[22:53] <jcoxon> yeah
[22:53] <jcoxon> push through the jetstream
[22:53] <Tiger^> right
[22:54] <jcoxon> just don't launch now :-D
[22:54] <Tiger^> ;)
[22:54] <jcoxon> jetstream is strong towards the see
[22:55] <Tiger^> it says: Volume at Release (cu. m): 3.33
[22:55] <Tiger^> at kaymont's site
[22:55] <Tiger^> for the KCI 1500
[22:55] <jcoxon> i'd play it more by ear
[22:55] <Tiger^> 3.33 isn't much
[22:55] <jcoxon> test the lift manually
[22:56] Action: jcoxon is a big fan of not doing calculations if possible
[22:56] <jcoxon> does get me in trouble occasionally
[22:56] <Tiger^> yeah, me too
[22:56] <jcoxon> HenryHallam, Robert has cleared up the PICAXE issue
[22:56] <Tiger^> i hate math
[22:56] <Tiger^> and it's mutual ;)
[22:57] <jcoxon> i also go for the crazy "soviet" style approach
[22:57] <jcoxon> stuff testing
[22:57] <jcoxon> just go for it
[22:57] <Tiger^> yeah, soviet testing rules :)
[22:57] <Tiger^> i'll try to get 3lbs on a spring scale
[22:57] <HenryHallam> PICAXE does exist, it's basically a branded PIC with special software that's a bit easier but a lot less capable
[22:57] <jcoxon> yeah
[22:57] <jcoxon> but he says for later on use a PICAXE
[22:57] <Tiger^> i just don't want the balloon to burst
[22:58] <Tiger^> as i've only ordered one
[22:58] <jcoxon> i'd skip it and move to something more powerful such as a balloon or gumstix
[22:58] <jcoxon> have you seen my pictures
[22:58] <jcoxon> those balloons are both smaller then yours
[22:58] <Tiger^> yup, i did
[22:58] <jcoxon> i promise you it won't burst
[22:58] <jcoxon> unless you pop it with a pin
[22:58] <HenryHallam> hm, I've just read that post but I disagree
[22:59] <HenryHallam> yeah james I think a gumstix is the way to go for more computing power
[22:59] <Tiger^> or unless someone shoots it down
[22:59] <Tiger^> ;)
[22:59] <jcoxon> Tiger^, hehe
[22:59] <HenryHallam> robert seems to want to use a less powerful and reliable chip to do the more complicated things??
[22:59] <jcoxon> i think he wants to make it more open to others to contribute
[22:59] <jcoxon> basic is so easy to program
[22:59] <HenryHallam> there is a C compiler for PICs which speeds up code development a lot at the expense of memory
[22:59] <HenryHallam> hmm
[22:59] <jcoxon> but its fine
[23:00] <jcoxon> we'll stick to the plan
[23:00] <HenryHallam> that's true but all the engineers have done a C course as part of the first year
[23:00] <jcoxon> once you are using C then move to a gumstix
[23:00] <HenryHallam> right
[23:00] <jcoxon> with gcc its so easy
[23:00] <HenryHallam> things like the sensor module might still want a separate microcontroller though, and either a PIC + assembler, PIC + C or PICAXE could be used for that
[23:01] <jcoxon> for the mini payload drop (need to think of a name for it)
[23:01] <jcoxon> yeah
[23:01] <jcoxon> do you think wire or servo/pin
[23:01] <HenryHallam> don't really know
[23:02] <HenryHallam> servo is a little trickier to do the hardware and software for
[23:02] <jcoxon> right got the name
[23:02] <jcoxon> Bellerophon
[23:02] <HenryHallam> hehe
[23:02] <jcoxon> hehe got thrown off pegasus
[23:02] <jcoxon> i feel its appropriate
[23:02] <jcoxon> poor nokia
[23:03] <HenryHallam> nice
[23:03] <HenryHallam> you know we should approach Nokia for sponsorship, think what they could do with that
[23:03] <jcoxon> :-D
[23:03] <jcoxon> after nova 1 definitly
[23:03] <jcoxon> no harm in emailing
[23:03] <HenryHallam> write letters, way better results
[23:04] <jcoxon> We use ~3.5" of 30awg Nichrome wire and heat it with either 2 each 2/3 A (6v) or 3 each 2/3 A (9v) lithium batteries. This is used to cut 215lb, 550lb, & 1000lb nylon cord. It will cut the cord in 3 to 5 seconds. The Nichrome is wound around the cord with 7 loops. This is the standard cutter that we use for NASA & NOAA. It is not affected by the cold & has been tested dozens of times to well over 100k ft.
[23:04] <jcoxon> Good luck
[23:04] <jcoxon> Craig
[23:04] <jcoxon> N7TSZ
[23:04] <jcoxon> look what i found
[23:04] <HenryHallam> nice
[23:05] <HenryHallam> how do you make connection to the nichrome? I'm concerned about using screw terminals in that environment, worried the thermal contraction might shake them loose
[23:05] <jcoxon> no idea
[23:05] <jcoxon> really not my field
[23:06] <Tiger^> screw terminals are the only way to go
[23:06] <Tiger^> nothing else would really hold
[23:07] <Tiger^> when the nicr gets hot
[23:07] <HenryHallam> ok
[23:07] <jcoxon> something i need to build before launch then
[23:07] <Tiger^> i've tested in on the ground
[23:07] <Tiger^> after freezing it with dry ice
[23:07] <HenryHallam> do you think Energizer would give us a crate of lithium batteries?
[23:07] <jcoxon> hehe
[23:07] <Tiger^> -78 degrees
[23:08] <Tiger^> worked like a charm
[23:08] <jcoxon> i've had so many of them
[23:08] <jcoxon> perhaps
[23:08] <HenryHallam> thanks Tiger, that's good to know
[23:08] <Tiger^> oh, i'd love a crate of lithium Energizers
[23:09] <HenryHallam> I'd also like to look into using Li-ions for the later balloons
[23:09] <HenryHallam> they have pretty good low temperature properties as well
[23:09] <Tiger^> for a flight, i need 4 or 6 AA's for the main bus
[23:09] <Tiger^> 4 for the cutdown
[23:09] <Tiger^> and 6 for the radio
[23:09] <Tiger^> times two - for testing
[23:10] <Tiger^> i wouldn't trust li-ons
[23:10] <jcoxon> not li-ions
[23:10] <HenryHallam> no?
[23:10] <jcoxon> just Li
[23:10] <HenryHallam> what's wrong with Li ions?
[23:10] <Tiger^> jcoxon: HenryHallam is talking about li-ion
[23:10] <Tiger^> i've seen them die in low temp
[23:10] <jcoxon> Li give better power to weight ratio
[23:10] <HenryHallam> ok
[23:11] <jcoxon> and temperature
[23:11] <HenryHallam> well if we can get lots of free lithium disposables then definitely use those
[23:11] <jcoxon> :-D
[23:11] <Tiger^> i'm wondering
[23:11] <HenryHallam> I had heard li-ion was supposed to be good for low temp though
[23:11] <jcoxon> i think lithium are better
[23:11] <HenryHallam> and anyway one of the objectives should be that the payload cabin doesn't get too cold
[23:11] <HenryHallam> for other people's payloads
[23:12] <jcoxon> true
[23:12] <Tiger^> polish regulations (EU regs, really) state that the balloon is classified as "light"
[23:12] <Tiger^> when, among other things
[23:12] <jcoxon> right
[23:12] <Tiger^> the cord between the payload and the balloon
[23:12] <Tiger^> requires a force of less than 230N to break it
[23:13] <Tiger^> 230N is 23kg
[23:13] <Tiger^> and how much force is that?
[23:13] <HenryHallam> that doesn't give you much margin for shock loads if you have a payload of more than a couple kg
[23:13] <jcoxon> right i've got to go
[23:14] <Tiger^> if it's more than a couple kg your balloon is classified as heavy
[23:14] <jcoxon> good chatting to you all
[23:14] <jcoxon> night
[23:14] <Tiger^> g'night jcoxon
[23:14] jcoxon (n=jcoxon@jac208.caths.cam.ac.uk) left irc: "Leaving"
[23:14] <Tiger^> i'm wondering where to get a cord like that
[23:14] <HenryHallam> well
[23:14] <HenryHallam> you only need a small piece of it
[23:14] <HenryHallam> in series with the main cord
[23:14] <Tiger^> it'd be pretty funny to enter a shop and ask for a cord that'll break under 23kg of force ;)
[23:15] <HenryHallam> I think some climbing ropes are "fusible" like that? maybe?
[23:15] <Tiger^> dunno
[23:15] <Tiger^> in the US, they have the same reg
[23:16] <Tiger^> and guys use a nylon cord
[23:16] <Tiger^> it doesn't look very... special :>
[23:16] malgar (n=malgar@adsl-ull-107-200.47-151.net24.it) left irc: "*** E' solo l'urto con un iceberg, che vuoi che sia, questa è una nave inaffondabile. *** 75$/barile"
[23:17] <Tiger^> maybe 23kg is a lot of force really
[23:17] <HenryHallam> just get some and test the maximum weight it can take, then peel off a proportionate number of strands?
[23:17] <Tiger^> i'm not sure that a line which breaks when *hit* with a force of 23kg
[23:18] <HenryHallam> a force is a force
[23:18] <HenryHallam> if you have a 23kg weight and give it a jerk, the force can be a lot more than 230N
[23:18] <Tiger^> is the same as the line which breaks when you suspend 23kg on it
[23:18] <HenryHallam> it depends on the acceleration of the jolt
[23:19] <Tiger^> and probably on a few other things, too
[23:20] <Tiger^> i think i'll go with a standard nylon cord
[23:20] <Tiger^> not too thick, not too thin ;)
[23:21] <HenryHallam> yeah I'm pretty sure nobody's actually going to demand you break your cord to show them
[23:21] <Tiger^> unless a plane hits it :(
[23:21] <Tiger^> or the chute fails and it hurts someone :(
[23:22] <Tiger^> i know i'm being paranoid
[23:22] <Tiger^> can't help it ;)
[23:22] <HenryHallam> I don't think it would damage a jet
[23:22] <Tiger^> me too
[23:23] <HenryHallam> or at least, it might take out an engine but that's why they have two
[23:23] <Tiger^> it'd probably just tear it to pieces
[23:23] <HenryHallam> if the chute fails and it hits someone on the head, that would hurt... but think about how many meteorites fall to earth every day and nobody's ever been hit by one
[23:23] <Tiger^> i sure wouldn't like to pay for a new Prat&Whittney jet engine :))
[23:23] <Tiger^> right
[23:24] <Tiger^> i'm more worried about a light propeller plane hitting it
[23:25] <Tiger^> but i'll have a permit
[23:25] <Tiger^> and a NOTAM will surely be issued
[23:25] <Tiger^> so i'll be clean ;)
[23:27] <HenryHallam> heh, you'd be a lot more scared if you know how many private pilots actually bother to check the notams
[23:27] <Tiger^> yeah, i know
[23:27] <Tiger^> but it's their fault
[23:27] <Tiger^> i would.
[23:28] <HenryHallam> I still do, but when you have to wade through literally 30+ pages of "airfield elevation changed from 39 to 40ft", "light out on low-rise crane" etc etc.. it gets old pretty quickly
[23:29] <HenryHallam> and besides there's not really a lot you can do to avoid a balloon anyway, other than keep a good lookout (which you should always do)
[23:30] <Tiger^> right
[23:52] <HenryHallam> then there's always the "big sky, small aeroplane" theory of collision avoidance
[23:53] <Tiger^> yeah
[23:53] <Tiger^> statistics ;)
[00:00] --- Mon May 1 2006