highaltitude.log.20090330

[01:16] sYx66 (n=wooh@bas1-kitchener06-1167865234.dsl.bell.ca) joined #highaltitude.
[01:36] bfirsh (n=ben@scooby.firshman.co.uk) left irc:
[01:39] Laurenceb (i=83e3dd23@gateway/web/ajax/mibbit.com/x-805ee0fab6962b8c) left irc: "http://www.mibbit.com ajax IRC Client"
[01:47] Laurenceb (i=83e3dd23@gateway/web/ajax/mibbit.com/x-bf8947e37403175f) joined #highaltitude.
[02:03] <Laurenceb> damn clocks changing
[02:03] <Laurenceb> I dont feel tired :-/
[02:08] <shellevil> ""
[02:09] <Laurenceb> I'm wondring if you could transmite psk with a radiometrix
[02:09] <shellevil> Eww...
[02:10] <shellevil> In theory, yes.
[02:10] <shellevil> In practice, ....
[02:10] <Laurenceb> well generating phase shifts isnt too hard
[02:10] <shellevil> I mean - constant volts - spike up or down enough to move an integrated total amount of pi or whatever
[02:11] <shellevil> just seems fun to calibrate
[02:11] <Laurenceb> but the problem is if you have varying numbers of phase transmitions its going to cause a frecuency shift
[02:11] <shellevil> DAC
[02:11] <Laurenceb> you can be off by 20% or more with the phase shift for one bit and it'll be fine
[02:11] <shellevil> Or I suppose appropriate filters and a constant voltage
[02:12] <Laurenceb> but if you add all those shifts up it will cause a frequency shift
[02:12] <Laurenceb> that depends ofn the number of phase transitions
[02:12] <shellevil> If you dont' care overmuch about spectral purity, you can whack it to nearly the rails for a very short moment.
[02:12] <Laurenceb> yeah
[02:13] <shellevil> Doing it nicely is going to be hard, and involve lots of thought
[02:13] <Laurenceb> but... its going to give a frequency shift...
[02:13] <Laurenceb> unless you use manchester encoding maybe...
[02:13] <shellevil> I don't see how it does
[02:13] <Laurenceb> no it doesnt help
[02:14] <Laurenceb> say to shift by pi*1.1
[02:14] <shellevil> oh
[02:14] <shellevil> right
[02:14] <shellevil> I think that if you're generating pure 1KHz - say
[02:14] <Laurenceb> lots of transitions shift the frequency
[02:15] <Laurenceb> you could use delay lines on the pcb
[02:15] <Laurenceb> or sample the rf...
[02:15] <shellevil> then you shift phase by 180 degrees at 1Hz say - then if you do it by modulating the voltage to make the transmitter shift up 10KHz for 50us, you'll get a sideband at 11KHz or so
[02:16] <shellevil> At least some energy there at the transitions
[02:16] <Laurenceb> not a problem for balloons
[02:16] <shellevil> No
[02:17] <shellevil> I don't see where the frequency shift comes in
[02:17] <Laurenceb> say you end up with 55us
[02:17] <shellevil> or are you just meaning accumulation from lots of 175 degree (say) shifts
[02:17] <Laurenceb> yes
[02:17] <shellevil> well - do it by modulating to +10 and -10KHz from the carrier for successive bits
[02:18] <Laurenceb> it may not be linear
[02:18] <shellevil> Then it doesn't matter if it's +175 degrees, and -175
[02:18] <shellevil> oh :/
[02:18] <Laurenceb> hmmactually
[02:18] <Laurenceb> you may be able to make a decoder
[02:18] <shellevil> Does the frequency shift actually matter?
[02:18] <Laurenceb> as the shift between sucessive bits will be pi
[02:19] <shellevil> Say PSK31
[02:19] <Laurenceb> as for the duration of each bit its at the carrier frequency
[02:19] <shellevil> If you've got 10 degrees error per symbol, that's only about 360 degrees per second
[02:19] <shellevil> or 1Hz
[02:19] <Laurenceb> no, PSK-31 uses amplitude modulation
[02:19] <Laurenceb> I'd have 300 baud data
[02:19] <Laurenceb> with a custom decoder
[02:20] <shellevil> I thought it was Phase Shift Key - 31(bps)
[02:20] <Laurenceb> it is
[02:20] <Laurenceb> but it uses amplitude modulation as well
[02:20] <Laurenceb> so ampltude is zero at phase transitions
[02:20] <shellevil> ah
[02:21] <shellevil> for spectral purity reasons
[02:21] <shellevil> Is psk actually better than fsk?
[02:23] <shellevil> this is for what freq?
[02:23] <Laurenceb> 434
[02:23] <Laurenceb> hmm I think a costas loop will work, if you use the arguments of the complex outputs, and compare one bin to the next
[02:24] <shellevil> yeah
[02:24] <Laurenceb> then you can see bit flips
[02:24] <Laurenceb> as a +-pi change
[02:24] <shellevil> assume not closed loop?
[02:24] <Laurenceb> the loop bandwidth of the filter will be very small so it only tracks the carrier
[02:24] <shellevil> 2 way comms that is
[02:25] <Laurenceb> dont follow
[02:25] <shellevil> then you could tell it 'left a bit, right a bit' and end up at precisely 180 degrees.
[02:26] <Laurenceb> thats an overkill
[02:26] <shellevil> yeah
[02:26] <shellevil> but if you've got 2 way anyway
[02:26] <shellevil> also - it'd lend itself to going to QPSK and friends.
[02:26] <Laurenceb> well chipcon modules are the way to go
[02:27] <shellevil> based on SNR
[02:32] <Laurenceb> the other way to do it is digital pll with a gps 1pps
[02:35] <shellevil> Silly to go that route, rather than just a tcxo, with a XOR gate on the output, then a filter.
[02:36] <shellevil> hmm
[02:36] <shellevil> 433, that does make crystals a bit more annoying.
[02:37] Action: shellevil looks at the $5 2GHz AD 4-quadrant multiplier in one drawer.
[02:37] <Laurenceb> what would you use for the frequency divider?
[02:37] <shellevil> I was meaning just a 433MHz oscillator off some form, then the multiplier as a modulator
[02:38] <Laurenceb> yeah, thats already on the module
[02:38] <shellevil> 433 is annoying - everything 'ttl' like craps out about 40
[02:38] <shellevil> to do PSK I mean
[02:38] <Laurenceb> would a standard pll ic work?
[02:39] <shellevil> you just flip the modulation voltage, and it works
[02:39] <shellevil> most don't go up that far
[02:39] <Laurenceb> frequcny multiplication wise you mean?
[02:39] <shellevil> No - i was meaning simply feed the bitstream - filtered a bit - to the 4 quadrant multiplier
[02:40] <shellevil> along with the sinewave from the transmitter
[02:40] <shellevil> and get a pretty good purity nicely modulated psk signal
[02:40] <shellevil> you'd need to buffer the output of course
[02:41] <shellevil> I haven't come up with a nice very cheap way to do a UHF PLL.
[02:41] <shellevil> They all tend to end up at either expensive chips, high power chips, or lots of chips
[02:41] <shellevil> Especially locking it to PPS is a bit annoying.
[02:48] <Laurenceb> AD have plenty of stuff
[02:48] <shellevil> yeah
[02:48] <Laurenceb> but 1pps make is hard
[02:48] <shellevil> none which _quite_ addresses it
[02:48] <Laurenceb> prob best to use a micro a frequency divider
[02:57] <Laurenceb> http://uk.farnell.com/on-semiconductor/mc100ep33dg/ic-sm-logic-ecl-divider/dp/1607665
[02:59] <shellevil> yeah - you'd need a couple to get to where you can use TTLish stuff
[03:00] <shellevil> TI has a neat 32 bit divider, readoutable by bytes
[03:00] <Laurenceb> ok
[03:38] Laurenceb (i=83e3dd23@gateway/web/ajax/mibbit.com/x-bf8947e37403175f) left irc: "http://www.mibbit.com ajax IRC Client"
[05:57] sYx66 (n=wooh@bas1-kitchener06-1167865234.dsl.bell.ca) left irc: Read error: 110 (Connection timed out)
[06:57] Simon-MPFH (n=simon@phantom.mpfh.co.uk) joined #highaltitude.
[08:25] rjharrison (n=rharriso@80.176.172.227) left irc: Read error: 110 (Connection timed out)
[08:25] rjharrison (n=rharriso@80.176.172.227) joined #highaltitude.
[08:30] icez (n=icez@unaffiliated/icez) left irc: Remote closed the connection
[08:37] Laurence (i=83e34f19@gateway/web/ajax/mibbit.com/x-f5a69851d2c81d5c) joined #highaltitude.
[08:37] <Laurence> yo
[09:25] <Laurence> SpeedEvil: for you 1wire netwrok, http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4338
[09:26] <Laurence> together with http://shop.tuxgraphics.org/electronic/detail_avrwebserver_smd4.html
[10:08] rjharrison (n=rharriso@80.176.172.227) left irc: Read error: 110 (Connection timed out)
[10:08] rjharrison (n=rharriso@vpn.hgf.com) joined #highaltitude.
[10:11] trialex (n=10330C9A@124-170-11-18.dyn.iinet.net.au) joined #highaltitude.
[10:14] trialex (n=10330C9A@124-170-11-18.dyn.iinet.net.au) left irc: Remote closed the connection
[10:30] rjharrison (n=rharriso@vpn.hgf.com) left irc: Read error: 113 (No route to host)
[10:31] rjharrison (n=rharriso@80.176.172.227) joined #highaltitude.
[10:32] Laurence (i=83e34f19@gateway/web/ajax/mibbit.com/x-f5a69851d2c81d5c) left irc: "http://www.mibbit.com ajax IRC Client"
[11:02] Laurenceb (i=83e34f19@gateway/web/ajax/mibbit.com/x-6641dfeffbe9aeaf) joined #highaltitude.
[11:02] <Laurenceb> greets
[11:41] <Laurenceb> SpeedEvil: ping
[11:41] <SpeedEvil> sorry - busy
[11:43] <Laurenceb> for you 1wire stuff, I was thinking build it into an rj11 double adaptor screwed onto the wall
[11:44] <Laurenceb> then inside http://shop.tuxgraphics.org/electronic/detail_avrwebserver_smd4.html and http://uk.farnell.com/maxim/ds2482s-800/i2c-to-1wire-bridge-8ch-16soic/dp/1606613?_requestid=64966
[11:47] <Laurenceb> if you have money to burn http://www.audon.co.uk/1-wire_modules.html
[12:08] <SpeedEvil> making own - sourcing from the internets.
[12:08] <Laurenceb> ok
[12:09] <Laurenceb> I like the idea of having RJ111 cables going out to the devices
[12:09] <Laurenceb> *RJ11
[12:10] <Laurenceb> then you could have a webserver in somehting like http://www.maplin.co.uk/Module.aspx?ModuleNo=22933&doy=30m3&C=SO&U=strat15
[12:10] <Laurenceb> power could be messy
[12:10] <Laurenceb> seperate power socket into the white box would be fugly
[12:11] <Laurenceb> http://shop.tuxgraphics.org/electronic/prod_avrwebserver_smd4.jpg you could dremel away a hole for the rj45 in the side
[12:12] <Laurenceb> do you have power over ethernet?
[12:15] <Laurenceb> if you hacked your router so theres power down the two unused pairs then you dont need a seperate supply for the 1wire server
[12:16] <Laurenceb> alternatively you could just have a big mess in a cabnite somewhere and forget about making it neat
[12:17] <Laurenceb> http://tuxgraphics.org/electronics/200903/hobby-poe.shtml
[12:20] <Laurenceb> hmm youd have to hack the cable or magjack...
[12:21] <Laurenceb> so not worth it
[12:23] <SpeedEvil> Going to use old PII/300 laptops I've got several of probably
[12:23] <Laurenceb> eats tons of power
[12:24] <Laurenceb> should be able to power that avr webserver off the router
[12:24] <SpeedEvil> About 7W
[12:24] <SpeedEvil> possibly replace with sheevaplugs, when they come down to $49
[12:24] <SpeedEvil> Because I believe that's happening soon.
[12:24] <SpeedEvil> Oh - yes - really.
[13:06] <Laurenceb> 7W is nice
[13:09] <Laurenceb> but do sheevaplugs have uk sockets?
[13:14] <SpeedEvil> will once I've finished with it
[13:15] <Laurenceb> hehe
[13:15] <Laurenceb> still seems an overkill to me.. guess if you want to host a nice user interface
[13:16] <SpeedEvil> I want to be able to plug in USB2 cams, and audio
[13:16] <Laurenceb> camwhoring?
[13:17] <SpeedEvil> outside cams, running 'motion'
[13:23] <Laurenceb> to spot the black helicopters?
[13:25] <SpeedEvil> No, just randoms that knock over my gatepost, and other fun stuff.
[13:26] <SpeedEvil> timechanges--
[13:26] <SpeedEvil> just went to post office, and it was shut.
[13:26] <SpeedEvil> All my clocks bar one auto-adjust
[13:27] <Laurenceb> http://tuxgraphics.org/electronics/200710/avr-ntp-clock.shtml
[13:41] <Laurenceb> how are you interfacing to the 1wire?
[14:08] <Laurenceb> hmm I could use that tuxgraphics server to together with a chipcon module to make an ip/balloon gateway
[14:25] <SpeedEvil> have a 1wire-usb gateway
[15:56] <Laurenceb> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294922322&Nr=AND(avl%3auk%2csearchDiscon_uk%3aN)&N=4294962569+4294955369+4294920272&Ns=stockPolicy_uk|1||new_uk|1&binCount=129#breadCrumb
[15:56] <Laurenceb> wonder if you could epoxy one of those onto a shaft... ?
[15:57] <Laurenceb> if the bore and shaft were "abused" first so it could grip well
[15:58] <shellevil> why?
[15:59] <shellevil> oh - your servo
[15:59] <shellevil> yes, you could do that
[15:59] <Laurenceb> yeah..
[15:59] <Laurenceb> for a parafoil
[16:00] <shellevil> two ways
[16:00] <Laurenceb> basically that on a geared motor
[16:00] <Laurenceb> I'd need feedback...
[16:00] <shellevil> either a ball race pressing the belt onto the gear, and guides
[16:00] <shellevil> Or two gears, bearings, and one driving gear
[16:00] <Laurenceb> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0471310
[16:00] <Laurenceb> that :P
[16:00] <shellevil> and a pickoff point glued somehow onto it
[16:01] <shellevil> that sort of thing, yes.
[16:01] <shellevil> though prolly smaller
[16:01] <Laurenceb> ideally there would be grayscale on the belt
[16:01] <shellevil> gray code
[16:01] <Laurenceb> are there linear grayscale readers?
[16:01] <Laurenceb> erm yes
[16:02] <shellevil> or you put a quadrature encoder on the driving shaft and a zero detector
[16:02] <shellevil> afk - hoovering car
[16:03] <Laurenceb> yeah but you have the problem of finding absolute pos
[16:04] <Laurenceb> I'd rather be able to read of absolute pos directly
[16:09] <Laurenceb> maybe you could use the belt as a big potentiometer
[16:10] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) joined #highaltitude.
[16:10] <aLeXBrEtOn> greets
[16:10] <Laurenceb> hi
[16:10] <Laurenceb> are belts conductive?
[16:11] <aLeXBrEtOn> belts?
[16:11] <aLeXBrEtOn> what sort?
[16:11] <Laurenceb> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=3384575
[16:12] <aLeXBrEtOn> doesn't look conductive to me
[16:12] <Laurenceb> looks like it has a lot of carbon black in it
[16:12] <aLeXBrEtOn> not metal for sure
[16:15] SpeedEvil (n=fjfjjf@tor/regular/SpeedEvil) left irc: Read error: 113 (No route to host)
[16:18] <aLeXBrEtOn> mmm
[16:18] <aLeXBrEtOn> been calling and emailing a lot lately
[16:18] <aLeXBrEtOn> emailed energizer and libelium
[16:18] <aLeXBrEtOn> and secured a 2nd deal with a local paper
[16:22] <Laurenceb> nice
[16:22] <Laurenceb> shellevil: I guess this http://www.active-robots.com/products/motorcon/quad-encoder/enc300.pdf
[16:22] <Laurenceb> together with maybe a micro switch and something clipped onto the belt to mark end of travel
[16:22] <Laurenceb> then you can calibrate the encoder
[16:24] sbasuita (n=sbasuita@unaffiliated/drebellion) joined #highaltitude.
[16:38] <shellevil> they may or may not be conductive
[16:38] <shellevil> depending on the carbon loading
[16:38] <shellevil> typically more 'static dissipative' than anything else.
[16:39] <Laurenceb> yeah
[16:39] <shellevil> or steal one from a mouse
[16:39] <Laurenceb> the other option is to stick a spur gear onto the toother belt pully
[16:39] <Laurenceb> and use it to drive a multiturn pot
[16:40] <Laurenceb> yeah, mice could help
[16:40] <shellevil> or the back of it for a hall sensor
[16:40] <shellevil> the back of the gear
[16:40] <Laurenceb> hmm yeah
[16:40] <shellevil> multiturn pot - sure.
[16:41] <shellevil> Find one rated for aa few K cycles and -40C tho :)
[16:41] <Laurenceb> yeah, it will be exposed
[16:41] <Laurenceb> at the front next to the belt drive
[16:41] <shellevil> Or pick a 50R pot and put it between the rails, so it won't feel the cold.
[16:42] <Laurenceb> hmm I think hall sounds good
[16:42] <shellevil> Or giant magnetoresistive.
[16:43] <shellevil> you can get magnetic sensor chips which output angle over I2C
[16:43] <shellevil> thogh that's maybe a little bit spendy for a simple thing.
[16:43] <Laurenceb> if you use a small toothed belt pully with a couple on magnets on, you could get reasonable resolution
[16:43] <shellevil> I was actually for the hall initiall meaning something like:
[16:44] <shellevil> hmm
[16:44] <shellevil> on reflection ascii diagrams suck
[16:44] <shellevil> anyway
[16:44] <Laurenceb> :P
[16:44] <Laurenceb> I only need about +-5mm belt position resolution
[16:45] <shellevil> A small disk magnet, oriented parallel with the gear surface
[16:45] <shellevil> Coaxially with the gear (well, not really, as you need the belt - but the same magnetically)
[16:45] <shellevil> you have a pole piece which reaches all the way round to the other side of the gear, leaving maybe a 15mm gap
[16:46] <shellevil> into this gap, you place a couple of hall sensors, with short pole pieces from them to almost touching the gear
[16:46] <shellevil> space the small pole pieces so that you get quadrature effect.
[16:46] <shellevil> Probably simpler to do than describe
[16:47] <shellevil> couple of minutes with an old bit of laminate from a transformer, and a hot-glue gun.
[16:47] <Laurenceb> http://docs-europe.electrocomponents.com/webdocs/0774/0900766b8077487e.pdf
[16:48] <Laurenceb> if I used the 16T2.5/12-2
[16:48] <shellevil> Oh - aluminium.
[16:48] <shellevil> You'll want to be using the special aluminium magnets then :)
[16:48] <Laurenceb> N45 :P
[16:50] <shellevil> Or brushless motor driving it, and count the steps.
[16:50] <Laurenceb> I'd use one of the big DC thingys
[16:51] <Laurenceb> with 200:1 gearbox
[16:57] <Laurenceb> aha http://docs-europe.electrocomponents.com/webdocs/00b3/0900766b800b345c.pdf
[17:05] <Laurenceb> probably not very accurate/temperatrure drift
[17:06] <Laurenceb> guess encoder on the back of the motor shaft is best
[17:23] <Laurenceb> http://www.quadratureencoders.com/products/encoders/incremental/rotary/kit/e4/
[17:33] <Laurenceb> its going to be spinning too fast :-/
[17:35] <shellevil> micros with quadrature units are cool
[17:36] <Laurenceb> http://www.quadratureencoders.com/products/encoders/absolute/rotary/shaft/ma3/
[17:36] <Laurenceb> thats nice :D
[17:38] <shellevil> I think that's the chip I referred t
[17:38] <shellevil> o
[17:38] <Laurenceb> not sure hot to mount it
[17:38] <shellevil> hot-melt
[17:38] <shellevil> or duct-tape.
[17:38] <Laurenceb> no, mechanism wise
[17:40] <Laurenceb> hmm if you could get belts with teeth on both sides
[17:45] <shellevil> I'd go with a little magnet glued to the cog, with a couple of hall sensors at 90 degrees - if that's adequate
[17:45] <Laurenceb> hmm http://www.active-robots.com/products/motorsandwheels/robotics-connections-gearhead.shtml
[17:49] <Laurenceb> that encoder looks managable
[17:50] <Laurenceb> its just a bit long
[17:50] <Laurenceb> - the motor assembly
[17:53] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) left irc:
[17:56] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) joined #highaltitude.
[17:57] <Laurenceb> it'd fit down some 80mm glass fibre tube
[18:00] fergusnoble (n=fergusno@82-71-15-97.dsl.in-addr.zen.co.uk) left #highaltitude.
[18:05] <aLeXBrEtOn> Anyone here know who owns Random Solutions?
[18:06] <aLeXBrEtOn> is it a UKHAS member?
[18:06] <Laurenceb> RocketBoy
[18:06] <aLeXBrEtOn> aha thanks ;-)
[18:07] <Laurenceb> hmm http://www.captrad.co.uk/Products/Product_Display.asp?Products_ID=78
[18:09] <sbasuita> Microsoft JET Database Engine error '80040e14'
[18:09] <sbasuita> Extra ) in query expression '([Products_Cat_ID] = )'.
[18:09] <sbasuita> ?
[18:09] <sbasuita> ; P
[18:11] <shellevil> Birdstrike to the JET engine.
[18:12] <sbasuita> hehe
[18:27] <Laurenceb> I'm off, cya
[18:27] Laurenceb (i=83e34f19@gateway/web/ajax/mibbit.com/x-6641dfeffbe9aeaf) left irc: "http://www.mibbit.com ajax IRC Client"
[18:41] hallam (i=126f3681@gateway/web/ajax/mibbit.com/x-023a8e76e0e553bc) joined #highaltitude.
[18:42] <hallam> hey all
[18:42] <hallam> anything new?
[18:42] <shellevil> not really.
[18:43] <shellevil> laurenceb has been trying to work out how to make a linear servo.
[18:43] <shellevil> and earlier how to do PSK on a FM module
[18:44] <aLeXBrEtOn> hallam, can you confirm that CU Spaceflight will be providing us with helium?
[18:50] <hallam> aLeXBrEtOn: I'll email the team now
[18:50] <aLeXBrEtOn> thanks very much
[18:50] <hallam> shellevil: did he manage to do PSK? That would be cool
[18:50] <aLeXBrEtOn> could you tell us exactly where the launch site is?
[18:51] <sbasuita> aLeXBrEtOn, it's churchill college
[18:51] <aLeXBrEtOn> ...more precise than that?
[18:51] <hallam> 52.2135, 0.0964
[18:51] <hallam> which school are you guys from?
[18:52] <sbasuita> hallam, reading school in reading, uk
[18:52] <hallam> ok
[18:54] <natrium42> hi
[19:02] <hallam> aLeXBrEtOn, I sent a link to your wiki to our mailing list along with the request.. could you maybe change your wiki to "Helium - we might be able to get free from CUSF" or something a little less certain? ;)
[19:03] <hallam> natrium42: any launches coming up?
[19:03] <aLeXBrEtOn> Ok thanks ;-)
[19:03] <natrium42> hallam, maybe in 2 weeks
[19:03] <natrium42> need to test picture downlink via iridium satellite
[19:04] <aLeXBrEtOn> natrium42, can you confirm that the GPS is being sent?
[19:04] <hallam> bad ass
[19:05] <natrium42> aLeXBrEtOn, i shipped it on friday
[19:05] <aLeXBrEtOn> many many thanks =)
[19:05] <natrium42> i estimate that you will receive it this friday
[19:05] <natrium42> sure thing
[19:05] <aLeXBrEtOn> great
[19:05] <natrium42> hallam, are you in US yet?
[19:05] <aLeXBrEtOn> we whittled our shopping list down by 60 pounds
[19:05] <natrium42> :)
[19:05] <aLeXBrEtOn> possibly 70 if we get free batteries
[19:05] <hallam> natrium42: yeah, Boston
[19:06] <natrium42> hallam, ah, cool :)
[19:06] <hallam> aLeXBrEtOn: if you succeed in getting batteries out of Energizer, please share the contact details :)
[19:06] <aLeXBrEtOn> sure
[19:06] <aLeXBrEtOn> the guy seemed fairly positive
[19:06] <shellevil> hallam: no - we were just kicking around ideas
[19:08] <hallam> they're actually a significant fraction of our launch expense
[19:08] <aLeXBrEtOn> we asked for 24 batteries
[19:08] <aLeXBrEtOn> quite a few
[19:08] <hallam> if you do end up having to buy them, www.7dayshop.com is good
[19:09] <hallam> good call
[19:09] <aLeXBrEtOn> enough for 2 tests and launch
[19:09] <hallam> though you could probably ask for a whole crate
[19:09] <aLeXBrEtOn> got bounced around the office quite a bit ;-)
[19:09] <natrium42> ask syx66 how he did it, i think he got them the day after he requested them
[19:10] <aLeXBrEtOn> heh
[19:10] <natrium42> crv3s too, which have higher power density than the AA
[19:11] <aLeXBrEtOn> yeah
[19:11] <natrium42> not sure how energizer makes the AA output 1.5 volts, might be a slightly different chemistry or a step-down converter
[19:11] <aLeXBrEtOn> it's just that the camera needs AAs ;-)
[19:11] <hallam> it's a different chemistry I think
[19:11] <natrium42> the voltage of crv3 cells is 3V
[19:12] <aLeXBrEtOn> yeah we go for lithium
[19:12] <aLeXBrEtOn> 'ultimate' I think
[19:12] <aLeXBrEtOn> how many batteries would the arduino + GPS + transmitter need?
[19:13] <natrium42> at least 4
[19:13] <natrium42> you should do a power budget
[19:13] <hallam> natrium42: I thought the L91 AAs had better energy-to-weight than CRV3s? (only a little)
[19:13] <aLeXBrEtOn> mm
[19:14] <aLeXBrEtOn> has anyone tried button cells?
[19:14] <hallam> no that's a terrible idea
[19:14] <aLeXBrEtOn> I guess they;re not very good individually
[19:14] <hallam> think of all the weight in the cases
[19:14] <aLeXBrEtOn> the big 3V ones...yeah I guess bad idea
[19:14] <aLeXBrEtOn> you'd need shitloads
[19:15] <hallam> yeah, and you can't solder to them, and they have a high internal resistance so you can't draw a decent current
[19:15] <aLeXBrEtOn> potato power anyone? :P
[19:15] <hallam> L91: 1.5V, 3Ah, 14.5g. CRV3: 3V, 3Ah, 32g
[19:16] <aLeXBrEtOn> my camera has a CRV3
[19:16] <hallam> though by the time you add the weight of a battery holder, the CRV3 with wires soldered directly to the terminals is lighter
[19:16] <aLeXBrEtOn> (not the balloon one)
[19:16] <hallam> A lot of cameras will accept either AAs or a CRV3
[19:16] <hallam> that's why the CRV3 is that weird shape
[19:16] <aLeXBrEtOn> yeah
[19:16] <aLeXBrEtOn> where exactly is the launch site then?
[19:17] <aLeXBrEtOn> churchill college...some sort of field?
[19:17] <hallam> I gave you the coordinates a couple of pages up
[19:17] <sbasuita> aLeXBrEtOn, yes
[19:17] <sbasuita> aLeXBrEtOn, watch the vids ;)
[19:17] <hallam> yeah it's a playing field
[19:17] <aLeXBrEtOn> great ;-)
[19:17] <hallam> not *enormous*, but big enough
[19:17] <aLeXBrEtOn> a not unbearable 2hr drive
[19:17] <aLeXBrEtOn> and then lots of motoring to find it
[19:17] <hallam> do you have someone to drive you there and do the chase?
[19:18] <sbasuita> hallam, my dad
[19:18] <aLeXBrEtOn> sbasuita's dad agreed
[19:18] <sbasuita> ; )
[19:18] <hallam> it's actually pretty easy to find from the M11
[19:18] <hallam> cool
[19:18] <hallam> do you have some kind of satnav?
[19:18] <sbasuita> aLeXBrEtOn, although he's a bit annoyed that nobody else is coming....
[19:18] <sbasuita> hallam, several
[19:18] <aLeXBrEtOn> dude, the press will be there
[19:18] <hallam> ok, you'll want that for the recovery
[19:18] <sbasuita> aLeXBrEtOn, get your dad to come
[19:18] <sbasuita> hallam, thought so
[19:18] <hallam> uh, the press?
[19:18] <aLeXBrEtOn> the Post said they'd be sending a photographer and a reporter
[19:18] <sbasuita> aLeXBrEtOn, they are?
[19:18] <sbasuita> wow
[19:18] <hallam> ok make sure it's low-key
[19:18] <natrium42> hallam, hmm, ok
[19:18] <aLeXBrEtOn> the Chronicle too as well
[19:18] <sbasuita> hah
[19:19] <natrium42> you're right
[19:19] <hallam> Churchill won't want too many people around
[19:19] <aLeXBrEtOn> yeah just 2 local newspapers
[19:19] <hallam> if I were you guys, I wouldn't want press around for my first launch, but that's up to you
[19:19] <aLeXBrEtOn> true, it could be a failure...
[19:19] <sbasuita> indeed
[19:19] <aLeXBrEtOn> but publicity is nice ;-)
[19:19] <sbasuita> aLeXBrEtOn, they gonna be chasing us as we scramble around in fields?
[19:19] <hallam> partly that, but also partly just that they're distracting and annoying
[19:20] <aLeXBrEtOn> no
[19:20] <hallam> you'll still get publicity if you contact them afterward and give them the photos
[19:20] <aLeXBrEtOn> indeed
[19:20] <aLeXBrEtOn> they didn't mention they would be at the launch site
[19:20] <aLeXBrEtOn> just said 'we'll book a photographer'
[19:20] icez (n=icez@unaffiliated/icez) joined #highaltitude.
[19:20] <hallam> maybe you could get them to come take photos of you at your school assembling it
[19:20] <sbasuita> aLeXBrEtOn, you need to be more clear ;)
[19:20] <hallam> school would like that, and it would be good for the paper too
[19:20] <aLeXBrEtOn> perhaps, perhaps
[19:21] <hallam> then send them the recovered photos after
[19:21] <hallam> hi icez
[19:21] <icez> hi
[19:21] <sbasuita> We may not even need school funding...
[19:21] <sbasuita> if the price is sub-100
[19:21] <aLeXBrEtOn> both said we need to wait till the launch is closer
[19:21] <sbasuita> i'm sure we can all afford to fork out 30 quid
[19:21] <aLeXBrEtOn> heh
[19:22] Laurenceb (i=83e3dd23@gateway/web/ajax/mibbit.com/x-5d85363c88ff9615) joined #highaltitude.
[19:22] <sbasuita> I think the advantage of getting publicity is that we can say to sponsors that they will get publicity ---> bigger and better freebies :D
[19:22] <Laurenceb> hello
[19:22] <Laurenceb> hi hallam
[19:22] <hallam> hey Laurenceb
[19:22] <aLeXBrEtOn> hi
[19:22] <hallam> PSK through a radiometrix, eh?
[19:22] <Laurenceb> stateside?
[19:22] <hallam> yeah
[19:22] <Laurenceb> one crazy idea I had
[19:23] <hallam> feedback from something listening to the output?
[19:23] Action: shellevil points the nutometer at Laurenceb. It reads 'peanut'.
[19:23] <Laurenceb> but I'm kind of working on a parafoil design
[19:23] <Laurenceb> atm
[19:24] <shellevil> pulse the input line for enough to shift by pi phase
[19:24] <hallam> hah
[19:24] <Laurenceb> its probably not worth doing psk with a radiometrix, but its possible if you write your own decoder
[19:27] <Laurenceb> as if your off my a few % it leads to a frequency shift that depends on the rate of bit flips
[19:28] <Laurenceb> you can get around that with an appropriately designed costas loop however
[19:30] <aLeXBrEtOn> gents, for the payload box:
[19:30] <aLeXBrEtOn> we have a big box
[19:30] <aLeXBrEtOn> shall we cut it down to size, or pack the big one full of insulation?
[19:30] <sbasuita> aLeXBrEtOn, cut it down
[19:30] <aLeXBrEtOn> need expert advice here
[19:30] <aLeXBrEtOn> more insulation=good
[19:31] <hallam> what's it made of, how big
[19:31] <aLeXBrEtOn> polystyrene
[19:31] <sbasuita> sizes on the wiki
[19:31] <aLeXBrEtOn> expanded
[19:32] <aLeXBrEtOn> 40x26x15
[19:32] <aLeXBrEtOn> cm
[19:32] <hallam> IMHO: get a slightly smaller box, or just use that one, don't cut it down
[19:32] <aLeXBrEtOn> length-width-height
[19:32] <hallam> you don't want it too small, because it's a pain to fit everything in
[19:32] <hallam> but that's fairly large
[19:33] <hallam> there's no real harm in it being bigger than it needs to be
[19:33] <hallam> you can add foam padding inside, though that's more to keep the stuff from rattling around rather than for extra insulation
[19:33] <hallam> the box itself should be enough for insulation even if it has a fair amount of empty space inside
[19:33] <hallam> space blanket on the outside is good too
[19:33] <hallam> not least because it looks cool
[19:35] <Laurenceb> whats happening stateside? are you just visiting?
[19:36] <hallam> yep, hanging out at MIT
[19:37] G8KHW (n=Steve@217.47.75.8) joined #highaltitude.
[19:37] <Laurenceb> :D
[19:38] <hallam> Hi Steve
[19:38] <G8KHW> Hi chaps
[19:38] <Laurenceb> hi
[19:46] <Laurenceb> http://www.srcf.ucam.org/cuspaceflight/rogallo
[19:48] <hallam> 120MB!
[19:50] <G8KHW> so I have noticed
[19:52] <G8KHW> I using my patent picture rotation solution (turn the laptop)
[19:53] <natrium42> Laurenceb, it looked like it was spinning quite a lot on ascent
[19:53] <Laurenceb> yeah
[19:53] <Laurenceb> it was going about 7m/s
[19:53] <Laurenceb> and the wing wobble was causing it to spin up
[19:54] <Laurenceb> it didnt cause any problems apparently
[19:54] <natrium42> ah, good
[19:54] <natrium42> otherwise you could make some sort of capsule :D
[19:54] <Laurenceb> the cutdown had a few stress fractures, so I've added some brass tube reinforcement
[19:54] <aLeXBrEtOn> we have a little dilemma here
[19:55] <aLeXBrEtOn> what will lose less heat: a small polystyrene box with space blanket, or a large polystyrene box with blanket + padding?
[19:56] <aLeXBrEtOn> need to run an experiment to solve that really
[19:56] <sbasuita> aLeXBrEtOn, the smaller one, cause it has less air, right?
[19:56] <aLeXBrEtOn> the bigger one, because it has more insulation, no?
[19:56] <aLeXBrEtOn> if we pack it full of foam and lagginf
[19:56] <hallam> it's all about surface area
[19:56] <sbasuita> aLeXBrEtOn, that's just adding more weight
[19:56] <aLeXBrEtOn> and the air is not true, since we will pack it full of foam
[19:56] <aLeXBrEtOn> yeah, foam weighs loads...
[19:56] <sbasuita> aLeXBrEtOn, rather have a smaller box
[19:57] <aLeXBrEtOn> bigger
[19:57] <aLeXBrEtOn> also stronger monocoque construction
[19:57] <aLeXBrEtOn> ;-)
[19:57] <sbasuita> aLeXBrEtOn, it's stronger if it's smaller
[19:57] <aLeXBrEtOn> monocoque...
[19:58] <hallam> the size of the box matters a lot less than other factors
[19:58] <aLeXBrEtOn> ideally we need both and do tests
[19:58] <hallam> the main one being, how well it's sealed
[19:58] <sbasuita> aLeXBrEtOn, we don't want to be filling up empty space
[19:58] <sbasuita> aLeXBrEtOn, want a snug fit from the beginning
[19:58] <hallam> why do you think that empty space inside is going to make it colder?
[19:59] <sbasuita> The electronics will produce heat, and if there is more air to heat, there is less hot air around the electronics?
[19:59] <hallam> if it's too snug it will be really annoying
[19:59] <hallam> but the air will all quickly reach an equilibrium temperature
[19:59] <hallam> unless it's being replaced by more cold air
[19:59] <hallam> hence the importance of sealing the edges
[20:00] <hallam> now a larger box will have more surface area to lose heat through, and more edge to let cold air in
[20:00] <sbasuita> hallam, we can't seal too well, else it will expand due to pressure, right? Or will we not be able to seal that efficiently anyway?
[20:00] <hallam> you won't be able to make it totally airtight unless you try really hard
[20:00] <hallam> but you can make it windproof / draught-proof
[20:00] <sbasuita> good
[20:00] <hallam> much like a house
[20:01] <aLeXBrEtOn> if it is sealed
[20:01] <aLeXBrEtOn> then more air is good
[20:01] <aLeXBrEtOn> air insulates
[20:01] <hallam> if it's sealed, then what's inside makes essentially no difference
[20:01] Action: sbasuita still hates the idea of having a huge box with little stuff
[20:01] <hallam> it then becomes dependent only on the thickness and surface areas of walls
[20:02] <hallam> you'll probably find that you have more stuff than you think
[20:02] <hallam> there'll be wires, cables, batteries, adapters
[20:02] <sbasuita> aLeXBrEtOn, I'm not sure why we're worrying about the box now anyway. We haven't even got any parts built ; P
[20:02] <Laurenceb> http://imagebin.org/43755
[20:02] <Laurenceb> ^thats my parafoil draft design
[20:03] <sbasuita> Laurenceb, nice
[20:03] <sbasuita> Laurenceb, would it be worth being able to control each wing individually?
[20:03] <aLeXBrEtOn> tasty
[20:03] <Laurenceb> I want to try COG shift
[20:05] <sbasuita> Hmm... none of us know anything about the process of sending ASCII through radio. Anybody care to give a few pointers?
[20:06] <hallam> you need to switch the TX pin on the Radiometrix module between two different voltages
[20:06] <sbasuita> hallam, right, so we're just sending binary pulses?
[20:06] <hallam> typically 1V and 1.2V or something like that
[20:07] <Laurenceb> I'm not sure how well a linear bearing will owrk on CF tube
[20:07] <hallam> the first voltage determines where in the 434.075MHz band your signal will be
[20:07] <hallam> the difference between the voltages determines the frequency shift
[20:08] <sbasuita> hallam, I thought 434.075 was exact, not a band?
[20:08] <hallam> so when the pin is 1.2V it might transmit on 434074500 Hz and when it's 1.0V it'll be 434074300 Hz
[20:08] <hallam> 434.075MHz is the nominal center freq of the band
[20:09] <hallam> the band extends 10kHz either side, if I remember right
[20:09] natrium42 (n=natrium4@CPE000625d867e2-CM0014045885be.cpe.net.cable.rogers.com) left irc: "Leaving"
[20:09] <hallam> anyway
[20:09] <sbasuita> hallam, so how do you compensate for the frequency shift on the receiving end?
[20:09] <hallam> hang on
[20:10] <hallam> you represent a binary 1, which is known as "mark", with a 1.2V level going into the TX pin, which produces a radio frequency of 434074500 Hz on the transmitter
[20:10] <Laurenceb> http://imagebin.org/43757
[20:10] <hallam> similarly binary 0, known as "space", is a 1.0V level on the TX pin, giving a radio frequency of 434074300Hz
[20:11] <Laurenceb> you could adapt that design to use the arduino
[20:11] <hallam> these numbers aren't exact, I'm just trying to get the idea across
[20:11] <hallam> Laurenceb is showing you a way to generate the 1.0V and 1.2V
[20:11] <hallam> now
[20:11] <Laurenceb> yeah, T1 sets the center frequency, and T2 the shift
[20:12] <hallam> on the receiver, let's say you tune it to 434073000 Hz
[20:12] <hallam> in "upper sideband"
[20:12] <hallam> the receiver effectively subtracts the tuned frequency from the received frequency
[20:13] natrium42 (n=natrium4@CPE000625d867e2-CM0014045885be.cpe.net.cable.rogers.com) joined #highaltitude.
[20:13] <hallam> so you'll hear an audio tone of (434074500 - 434073000) = 1500Hz when the transmitter is sending a mark
[20:13] <hallam> and 1300Hz when it's sending a space
[20:13] <hallam> with me so far?
[20:14] <sbasuita> Hmm... I'm not understanding that circuit
[20:14] <sbasuita> But then I don't take electronics
[20:14] <sbasuita> : O getting major lag, sorry
[20:14] Simon-MPFH (n=simon@phantom.mpfh.co.uk) left irc: Read error: 104 (Connection reset by peer)
[20:14] <hallam> don't worry about the circuit for now
[20:14] <hallam> do you understand what I've said about the voltages and frequencies?
[20:14] <sbasuita> hallam, yep
[20:15] <hallam> ok
[20:15] Simon-MPFH (n=simon@phantom.mpfh.co.uk) joined #highaltitude.
[20:15] <hallam> obviously if you tune the receiver to a different frequency, you'll hear different audio tones
[20:15] AdrianB (n=a@216.183.92.181) got netsplit.
[20:15] akawaka (n=akawaka@bunyik.akawaka.net) got netsplit.
[20:15] <hallam> similarly if the transmitter frequency changes because it gets cold
[20:16] <hallam> so you might hear 500Hz for space and 700Hz for mark, or 2000Hz and 2200Hz
[20:16] <sbasuita> hallam, oh right, so we don't have to worry about _constantly_ retuning the receiver because of temperature change?
[20:16] <hallam> right
[20:16] AdrianB (n=a@216.183.92.181) returned to #highaltitude.
[20:16] akawaka (n=akawaka@bunyik.akawaka.net) returned to #highaltitude.
[20:16] <hallam> it drifts fairly slowly
[20:16] <hallam> and you don't have to get it perfect
[20:16] <hallam> the point is that as long as the receiver is tuned to within about 4kHz of the transmitter, you'll hear the tones
[20:16] <sbasuita> hallam, ah, that's all much clearer now :)
[20:17] <Laurenceb> just keep an eye on it, adjust every few minutes
[20:17] <hallam> and the tones will keep their 200Hz spacing
[20:17] <sbasuita> And I guess fldigi will handle conversion of the binary back to ASCII
[20:17] <hallam> then you have computer software that listens to the audio tones and decides whether it's hearing a 1 or a 0
[20:17] <sbasuita> Based on the tones
[20:17] <hallam> right, exactly
[20:17] <sbasuita> that's really neat
[20:17] <hallam> there's a bit more yet
[20:17] peddie (n=matthew@PEDDIE.MIT.EDU) left irc: Remote closed the connection
[20:17] peddie (n=matthew@PEDDIE.MIT.EDU) joined #highaltitude.
[20:18] <hallam> hey peddie, cocoa tonight?
[20:18] <hallam> sbasuita: you have to get the timing right on the transmission
[20:19] <hallam> so first you decide on a "baud rate"
[20:19] <hallam> which is how fast the bits are going to be sent
[20:19] <hallam> 50Hz is good
[20:19] <hallam> so each bit is 20ms long
[20:19] <hallam> for each byte, you first send a "start bit", which is always "space" / 0
[20:20] <hallam> then you send the least significant bit of the byte
[20:20] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) left irc:
[20:20] <hallam> then the other 7 bits, ending with the most significant bit
[20:20] <hallam> and then a "stop bit", which is always "mark" / 1
[20:20] <hallam> then if you're not going to send another byte immediately, you keep transmitting mark / 1
[20:21] <hallam> because that's the "idle" state
[20:21] <sbasuita> hallam, ok, that's all understood
[20:21] <hallam> when you send the next byte, you start with another start bit, etc
[20:21] <hallam> yeah it's not too bad
[20:21] <sbasuita> hallam, is there a name for that transmission protocol?
[20:22] <hallam> it's the standard asynchronous serial protocol
[20:22] <hallam> or RTTY when applied to radio transmission
[20:22] <sbasuita> hallam, great, thanks for the crash course :)
[20:22] <hallam> most serial ports use the same scheme, just different voltages for 1 and 0
[20:22] <hallam> np
[20:23] Action: sbasuita sends daniel some copypasta
[20:23] <hallam> easiest way to do it on the arduino is probably with a 50Hz timer interrupt
[20:24] <hallam> you can get C code that does it on the CUSF wiki, and translate that to arduino
[20:24] <hallam> sorry the CUSF svn
[20:25] <hallam> http://www.srcf.ucam.org/~cuspaceflight/websvn/filedetails.php?repname=CUSF&path=%2Frocket_board%2Ffirmware%2Fmmc_example%2Flpc2k%2Fmain.c
[20:25] <hallam> radio_proc() in there
[20:25] <hallam> it's called with a 1000Hz interrupt
[20:26] <hallam> although that one uses 7-bit ASCII instead of 8-bit
[20:26] <hallam> which is slightly faster, fergusnoble prefers to do it that way, I usually prefer 8-bit but the UKHAS standard seems to be 7-bit now
[20:26] <Laurenceb> 1KHz?
[20:27] <Laurenceb> why?
[20:27] <Laurenceb> you doing pulse shaping?
[20:28] <hallam> nah, it was just convenient to attach it to a 1kHz interrupt from the SD card library
[20:28] <Laurenceb> ah
[20:28] <hallam> also allows a (limited) selection of baud rates
[20:29] <Laurenceb> this is the rocket board?
[20:29] <hallam> yeah, needed something quick and dirty for nova 10
[20:29] <Laurenceb> i see
[20:30] <Laurenceb> hmm any idea if linear bearings will work on CF tube?
[20:30] <hallam> what's a linear bearing?
[20:31] <Laurenceb> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294957561&N=4294954927
[20:31] <hallam> it's just a block of metal with a hole in it?
[20:31] <sbasuita> hallam, I thought ASCII was 7 bits only?
[20:32] <sbasuita> When you say 8 bit, do you mean with parity?
[20:32] <Laurenceb> some of them are... some have ball bearings if I understand it
[20:32] <hallam> no, no parity
[20:32] edmoore (n=edmoore@chu-gw.churchillcambridge.co.uk) joined #highaltitude.
[20:32] <hallam> the 8th bit can be for extened ascii (gets you luxuries such as the pound sign)
[20:32] <edmoore> rjharrison: good banter for you sir
[20:32] <hallam> but more importantly, it's useful for sending binary data
[20:32] <hallam> hi edmoore
[20:32] <sbasuita> hallam, oh right, the extended codes
[20:33] <sbasuita> hallam, is it worth doing parity?
[20:33] <hallam> maybe? I don't think anyone here has tried it
[20:33] <edmoore> hallam: have never had an issue with other people using churchill. As long as one of us is around it's basically to be encouraged
[20:33] <edmoore> rjharrison: ping
[20:33] <hallam> personally I'd just go straight to a more capable error-correcting code rather than even/odd parity
[20:34] <hallam> edmoore: cool, just thought I'd check with the list
[20:34] Action: Laurenceb is using mfsk
[20:34] <hallam> sbasuita: sounds like you're okay to use the CUSF launch site. We'll get back to you about the helium but I'd say it's very likely you can have some
[20:34] <edmoore> hallam: we're talking at the AMSAT Colloquia this year
[20:34] <sbasuita> hallam, thanks a bunch :)
[20:34] <edmoore> Manchester July
[20:35] <hallam> edmoore: sweet
[20:35] <edmoore> just so you know :p
[20:35] <edmoore> met all the AMSAT and RSGB cheese today
[20:35] <edmoore> had a linkup with the ISS at parkside
[20:35] <edmoore> was quite amazing
[20:35] <hallam> oh cool, did it go well?
[20:35] <edmoore> the sharp intake of breath when you got the first crackles of contact with the ISS all around the auditorium was really visceral
[20:36] <hallam> I was reading today about some AMSAT people that managed to bounce a signal off Venus
[20:36] <edmoore> it hit you in the chest, almost like that bit in Apollo 13 when they get radio contact back after re-entry
[20:36] <hallam> hehehe
[20:36] <sbasuita> / Do radio shizzle
[20:36] <sbasuita> void radio_proc() {
[20:36] <sbasuita> interesting code comments ;P
[20:37] <hallam> which astronaut was it, Fincke?
[20:37] <Laurenceb> venus bounce?!
[20:37] <hallam> sbasuita: we were tired
[20:37] <Laurenceb> now thats extreme
[20:37] <hallam> Laurenceb: apparently it's a test for the transmitter they're plannign to use for the first Mars AMSAT
[20:37] <edmoore> hallam: Simonyi
[20:37] <hallam> oh right
[20:37] <hallam> makes sense
[20:37] <hallam> was Madsen there?
[20:37] <edmoore> nope
[20:37] <edmoore> away today
[20:38] <edmoore> but I showed them his photos of Soyuz 14
[20:38] <edmoore> and the video
[20:38] <hallam> nice shot of him with the hockey shirt in front of Soyuz
[20:38] <edmoore> they had decent sound in the auditorium too so it had some impact
[20:38] <edmoore> yes, love that one
[20:38] <edmoore> rjharrison: ping-a-ding-a-ling
[20:38] <hallam> http://www.amsat-dl.org/pic/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=7561
[20:39] <Laurenceb> http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6174747 <-- is there any point to that over metal with a hole in it?
[20:39] <edmoore> so the head of amsat uk, who Jim Heck said we should meet pretty soon, is one Martin Sweeting
[20:40] <Laurenceb> hmm he sounds familiar
[20:40] <hallam> yeah he's surrey, isn't he?
[20:40] <Laurenceb> yes
[20:40] <Laurenceb> /s
[20:40] <edmoore> Prof. Sir Martin Sweeting, founded SSTL
[20:41] <hallam> Prof. Sir., that's pretty good
[20:41] <hallam> and he gets to follow it with a callsign
[20:43] <rjharrison> Hi all
[20:43] <Laurenceb> is COG shift on a parafoil a good/bad idea?
[20:43] <Laurenceb> hi
[20:43] <hallam> hi rjh
[20:44] <edmoore> rjharrison: so one of the guys today told me who it was whose toes you trod on with 434.650
[20:44] <rjharrison> Hehe
[20:44] <edmoore> and they definitely definitely heeard you, if that's anything of a clue
[20:45] <rjharrison> Who was it?
[20:45] <rjharrison> MOD ?
[20:45] <edmoore> DoD
[20:45] <edmoore> and looks like a sand castle
[20:45] <Laurenceb> what? a balloon flight?
[20:45] <edmoore> no more clues. Although I just gave it away.
[20:47] <Laurenceb> http://www.swg.usace.army.mil/pao/Sandcastle/SandCastleFeb03.pdf
[20:47] Action: Laurenceb fails
[20:50] <hallam> only 98 more balloons and you too can emulate a German pop song
[20:50] <Laurenceb> Menwith Hill ?
[20:51] <edmoore> god, lots of list activity today
[20:51] <hallam> you have it auto-filtered, right?
[20:52] <edmoore> yep
[20:52] <edmoore> but basically
[20:52] <edmoore> i am away tues night and wednesday
[20:52] <edmoore> I have no idea if helium arrived today
[20:52] <edmoore> never got a phone call from anyone
[20:53] <hallam> it's a bit moot anyway since they'll need you to get to the gas
[20:53] <edmoore> I spent £500 on my car to get it to pass it's MOT (yes) and 60% of my miles were CUSF in the last year
[20:53] <hallam> we should recruit more Churchillians
[20:53] <edmoore> so things are definitely going to chnage on re-embezzlement
[20:53] <hallam> have you been going with the standard 50p/mile or whatever it is?
[20:53] <edmoore> no, just charging for petrol
[20:54] <hallam> oh yeah, that should change
[20:54] <edmoore> but i just got raped on wear and tear. so I guess I may have to upgrade things a bit
[20:54] <edmoore> because £500 is just not funny. I almost burst into tears
[20:55] <hallam> http://www.theaa.com/allaboutcars/advice/advice_rcosts_petrol_table.jsp
[20:55] <hallam> what was your annual mileage?
[20:56] <edmoore> ~10k ish
[20:56] <edmoore> well probs a bit less
[20:57] <G8KHW> edmoore: re your PM Q last night - the answer is not yet
[20:57] <edmoore> looks like 50p is the right number
[20:57] <hallam> looks like 50p/mile isn't too far off then
[20:57] <edmoore> G8KHW: ok sorry about that, I left it with someone else. Will chase right away
[20:57] <G8KHW> NP
[20:58] <hallam> but you seriously drove 5000 miles for CUSF?
[20:59] <edmoore> amazing how it adds up
[21:00] <hallam> that's dedication
[21:00] <edmoore> most of it was probably nova 7 - that was about 1000 miles in one mission :)
[21:00] <hallam> I was looking at those latest sims that were emailed aroun
[21:01] <edmoore> oxford to cam, cam to felixstowe, felixstowe to cam, cam to manchesterish, manchesterish to cam, cam to oxford
[21:01] <edmoore> all in about 16 hrs
[21:01] Xenion (n=robert@p579FC8DE.dip.t-dialin.net) joined #highaltitude.
[21:01] <hallam> I think it would be pretty cool to make a program that would play with the various degrees of freedom to put the landing site right where you want it
[21:01] <hallam> gas fill, launch time, descent rate
[21:01] <hallam> within reasonable bounds
[21:01] <Laurenceb> monte-carlo
[21:02] <hallam> who needs a Rogallo when you have a really good predictor ;)
[21:03] <hallam> of course, it does mean you'd need to really be able to hit an exact launch time and fill
[21:03] <Laurenceb> someone who want to land back at the launch site
[21:03] <hallam> Laurenceb: check email
[21:04] <Laurenceb> haha
[21:04] <Laurenceb> ok I'll take that back
[21:06] DanielRichman (n=DanielRi@89.243.213.125) joined #highaltitude.
[21:06] <DanielRichman> can anyone point me in the right direction for the protocol that you guys would use to talk balloon to ground?
[21:07] <edmoore> hallam: assembled and dissassembled GB4FUN today with Carlos Eavis
[21:07] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) joined #highaltitude.
[21:07] <edmoore> gosh - it would be the best mobile tracking station/workshop in the history of ever
[21:07] <sbasuita> (in terms of ASCII, not serial ; P )
[21:07] <Laurenceb> didnt even take really tweaked inputs
[21:08] <edmoore> hallam: i think we have few enougb parameters that we might be able to get an analytical solution
[21:08] <edmoore> and solve it for params
[21:08] <edmoore> but basically monte carlo would be so much easier :0
[21:08] <Laurenceb> your wind is a 3D numerical function
[21:08] <hallam> isn't the flight-path prediction numerical?
[21:08] <hallam> right
[21:09] <hallam> edmoore: I've not seen GB4FUN, is it some kind of portable ham shack?
[21:09] <hallam> sbasuita / DanielRichman : on the UKHAS wiki I believe
[21:09] <DanielRichman> hallam, any idea of the page name? couldn't find it or maybe I'm looking for the wrong thing. sorry ;)
[21:09] <edmoore> hallam: yes
[21:10] <edmoore> and really well kitted out
[21:10] <edmoore> az el rotators, large plasma screen with all the sat positions, glossy and glistening kit
[21:11] <hallam> oh, shiny
[21:11] <sbasuita> hallam, couldn't track it down
[21:11] <hallam> sbasuita: yeah I can't see it either. Best ask jcoxon for the details
[21:12] <Laurenceb> edmoore: what... in a car?
[21:12] <edmoore> no
[21:12] <sbasuita> I'm sure i've got this in my logs....
[21:12] <edmoore> in a trailor
[21:12] <Laurenceb> ok
[21:12] <edmoore> sbasuita: what's the question?
[21:12] <hallam> but it's something like $$ALIEN, time, lat, lon, alt, ...
[21:12] <hallam> UKHAS standard telem format
[21:12] bfirsh (n=ben@scooby.firshman.co.uk) joined #highaltitude.
[21:12] <sbasuita> yes
[21:13] <edmoore> give me 1 sec
[21:13] <Laurenceb> http://englishrussia.com/images/art_modify/21.jpg
[21:13] <DanielRichman> Ok. Totally different topic. Is it worth trying to get the AVR CPU to 'sleep', ie. consume less power than just rolling around in a for(;;) loop waiting for something to happen? is it possible?
[21:14] <hallam> probably possible, probably not worth it
[21:14] <Laurenceb> yes its poss, but probably not worth it for what your doing
[21:14] <DanielRichman> Okey
[21:14] <edmoore> $$ <CALL SIGN>, <INCREMENTAL COUNTER D>, <TIME HH:MM:SS>, <LATITUDE DD.DDDDDD>, <LONGITUDE DD.DDDDDD>, <ALTITUDE METERS MMMMM>
[21:14] <edmoore> then whatever u want, irrc
[21:14] <DanielRichman> edmoore, does it require a terminating comma before you tack any rubbish onto the end?
[21:14] <edmoore> probably
[21:14] <hallam> probably a good idea
[21:14] Action: DanielRichman notes that down
[21:15] <sbasuita> edmoore, there is a space between $$ and callsign?
[21:15] <hallam> DanielRichman: bung it on the wiki
[21:15] <hallam> no space
[21:15] <DanielRichman> hallam, shall I put it on an ALIEN page or a general page?
[21:15] <edmoore> sbasuita: no, that is a typo
[21:15] <hallam> general
[21:15] <edmoore> although it doesn't really matter or break anything
[21:15] <sbasuita> What is the incremental counter?
[21:15] <edmoore> seconds since.... something
[21:15] <edmoore> launch/reset
[21:16] <hallam> or it could just be 1 for the first message, 2 for the second, etc
[21:16] <edmoore> it's there because we have it and we're the ones who influence the standard
[21:16] <rjharrison> or just the incremental number of the data lines sent
[21:16] <hallam> I think it just has to be any number that increases from one message to the next
[21:16] <sbasuita> DanielRichman, probs just ms since poweron methinks?
[21:16] <edmoore> basically yes
[21:16] <edmoore> it's a good identifier for the string
[21:17] <edmoore> seeing as there'll be strings coming in from all sorts of different stations at different times on the teacker
[21:17] <rjharrison> especially when different people recieve different data for the same line
[21:17] <sbasuita> DanielRichman, do you happen to have one of those 3g dongle internet thingies?
[21:17] <DanielRichman> sbasuita, ms since poweron will be messed up if we try using software serial
[21:17] <rjharrison> Thinking of embarrasing alt incident
[21:17] <DanielRichman> sbasuita, no
[21:17] <sbasuita> That would be SUPER useful out in the field
[21:18] <DanielRichman> sbasuita, haha. I think you can get your phone hooked up (nokia) and access the internet - however, that requires some windows rubbished called Nokia PC Suite
[21:18] <sbasuita> DanielRichman, why can't we do time since poweron?
[21:19] <sbasuita> BTW, the first two links in the Links section on wiki.ukhas.org.uk are 404
[21:19] <hallam> you can get wifi in the Churchill bar, which is a short walk from the launch field - not sure if you can actually get it on the field, edmoore?
[21:19] <DanielRichman> sbasuita, Because in order for software serial to work properly, it has to use this function called delayMicroseconds instead of delay. Delaymicroseconds, in order to work, relies on the frequency of the cpu and then rolls around in nops or whatever until time is up. However, in order for that to work accuratly the arduino library disables all interrupts - including the one that counts ms since poweron.
[21:19] <sbasuita> DanielRichman, that's the biggest pain ever.
[21:20] <edmoore> hallam: you can get it from the moller centre
[21:20] <edmoore> tis nearer
[21:20] <hallam> ok
[21:20] <rjharrison> just add 1 each time you tx a sentance and you'll be fine
[21:20] <edmoore> a cantenna would be a good purchase though
[21:20] <DanielRichman> sbasuita, I told you arduino library was terrible
[21:20] <hallam> wow, I'm so glad I don't use arduino
[21:20] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) left irc:
[21:20] <sbasuita> hallam, edmoore, I meant "out in the field" as driving around the countryside ; )
[21:20] <hallam> DanielRichman: I guess that means you'll have to do the radio transmission in a "blocking" way, as well
[21:21] <hallam> 3G is useful for that, but not essential
[21:21] <sbasuita> DanielRichman, we can still ditch the arduino....
[21:21] <edmoore> sbasuita: we have something of a secret database
[21:21] <edmoore> of open wifi spots in the countryside
[21:21] <DanielRichman> sbasuita, hallam, could just avoid software serial
[21:21] <sbasuita> DanielRichman, how?
[21:21] <edmoore> it's not a secret anymore....
[21:21] <sbasuita> heh
[21:22] <DanielRichman> sbasuita, GPS on RX phone on TX, baudrate providing... or switch between devices with transistors, giving both the UART when they need it, etc. I dunno
[21:22] <DanielRichman> sbasuita, priority no. one for me, is avoid software serial.
[21:22] <hallam> software serial does kind of blow even on things that aren't Arduinos
[21:22] <sbasuita> hallam, how do you mean?
[21:22] <DanielRichman> edmoore, hallam, the string/protocol above ($$ .....) - does that end in a newline or not?
[21:22] <hallam> it's just annoying and fiddly
[21:23] <DanielRichman> hallam, Yeah. I wish arduino has two uarts
[21:23] <DanielRichman> the Arduino mega has four but its £50
[21:23] <hallam> newline is convenient to read it directly in fldigi, but not required for the distributed tracker
[21:23] <sbasuita> DanielRichman, think we should ditch the arduino?
[21:23] <sbasuita> It would mean having to spend some money...
[21:23] <hallam> you could do it with one UART the way you were describing
[21:23] <hallam> the baud rates dont' have to be the same, you can switch baud rates
[21:23] <edmoore> don't ditch the arduino
[21:24] <edmoore> the hardware is fine
[21:24] <edmoore> perfectly good
[21:24] <DanielRichman> hallam, yeah. The phone is the only other device requiring the UART... and that only is required when we land
[21:24] <Laurenceb> you can load hex files with gcc
[21:24] <edmoore> that is the asnwer
[21:24] <edmoore> rjharrison: tell them it's easy
[21:24] <Laurenceb> indeed
[21:24] <DanielRichman> so just switch, change baudrate, go go go!. Swap back. The phone protocol (AT) is (afaik) very command-response like, so the phone won't be jabbering to us while we're not listening
[21:24] <edmoore> rjharrison: did this learning curve (actually bloody fast) not so long ago. Don't be afriad, dive in
[21:25] <edmoore> should be no colon in the above message
[21:25] <DanielRichman> edmoore, winavr? eww.
[21:25] <Laurenceb> hehe yeah I use avr studio
[21:25] <Laurenceb> in ubuntu its very nice
[21:25] <DanielRichman> I use VI.
[21:25] <sbasuita> DanielRichman, you use vim ;P
[21:25] <sbasuita> you're not _that_ hardcore
[21:26] <Laurenceb> getting windows to work properly with avrs is a pain
[21:26] <edmoore> I use ed
[21:26] <Laurenceb> ubuntu its just an apt-get job
[21:26] <hallam> I think the point is that you can use the arduino hardware without the hand-holding, crippled arduino software environment
[21:26] <sbasuita> hallam, that's the plan
[21:26] <Laurenceb> yeah
[21:27] <hallam> sounds reasonable
[21:27] <edmoore> http://digg.com/programming/xkcd_Real_Programmers
[21:27] <Laurenceb> the bootloader will run from avr-dude IIRC
[21:27] <DanielRichman> edmoore, you should send your camera up on butterflies
[21:27] <edmoore> whoops. digg? why the f* is that the top hit
[21:27] <edmoore> http://xkcd.com/378/
[21:28] <sbasuita> DanielRichman, we might as well just use Tx for phone and Rx for GPS then
[21:28] <sbasuita> DanielRichman, I'd rather not have to mess about guessing if we've landed
[21:28] <DanielRichman> sbasuita, we'll see. Need you to find some docs on AT though
[21:28] <sbasuita> DanielRichman, already have
[21:29] <edmoore> sbasuita: it's not call guessing
[21:29] <edmoore> we prefer the term foxhunting
[21:29] Action: Laurenceb saddles up
[21:29] Action: Laurenceb flees from PETA
[21:29] <DanielRichman> sbasuita, docs on the baudrate etc.
[21:30] Simon-MPFH (n=simon@phantom.mpfh.co.uk) left irc: "Leaving"
[21:34] <Laurenceb> hmm so you have gps,phone, and radio ?
[21:36] <DanielRichman> who, Laurenceb?
[21:36] <Laurenceb> on your payload
[21:36] <sbasuita> Laurenceb, yes
[21:36] <DanielRichman> yeah, that's right (weight providing). We're also shoving in some temperature sensors
[21:36] <Laurenceb> IMO using the uart for the gps and phone, then bit bang the radio
[21:36] <hallam> I think that's what they're planning
[21:37] <Laurenceb> sounds sinsible, but doubt you'll do it with arduino api
[21:37] <hallam> unless you really have UARTs out the wazoo, there's not much point using one for the radio
[21:37] <DanielRichman> Laurenceb, what way would you switch between the UART for the GPS or Phone? transistors disconnecting one and connecting the other or having one on RX and one on TX?
[21:37] <Laurenceb> IMO thats a faf
[21:37] <hallam> just always have GPS on RX, phone on TX
[21:37] <Laurenceb> may as well bit bang the radio
[21:37] <DanielRichman> Okey.
[21:37] <hallam> as long as the phone can work like that, which it probably can
[21:37] <edmoore> agreed
[21:38] <edmoore> bit bang to the gps if you ever need to talk to it
[21:38] <DanielRichman> I'm hoping that the phone will work like that :)
[21:38] <DanielRichman> edmoore, hopefully should work out of the box
[21:38] <Laurenceb> I've used ericssons like that
[21:38] <sbasuita> Sounds like a plan.
[21:38] <edmoore> sure, you you'll want to try the priopriatry protocol before long :p
[21:38] <edmoore> which gps are you using?>
[21:38] <sbasuita> edmoore, lassen iq
[21:38] <edmoore> cool, we have it on badger
[21:39] <edmoore> as henry has probably already told you
[21:39] <sbasuita> Laurenceb, what ericssons have you used? I've got the official AT command docs, but no info on hooking up. Know the baudrate?
[21:39] <edmoore> we use the proprietary protocol for that
[21:39] <edmoore> connections.ru isn't it?
[21:39] <edmoore> or something
[21:39] <edmoore> pinouts.ru
[21:39] <edmoore> pinup.ru
[21:39] <edmoore> ru.ready.for.love
[21:39] <Laurenceb> ti-68i
[21:39] <DanielRichman> edmoore, sbasuita found pinouts
[21:40] <sbasuita> pinouts is looking dodgy
[21:40] <sbasuita> Laurenceb, http://pinouts.ru/CellularPhones-P-W/sony_ericsson_j100_pinout.shtml
[21:40] <sbasuita> what do you think?
[21:40] <sbasuita> i've got a w800i
[21:40] <Laurenceb> looks familiar
[21:41] <sbasuita> Laurenceb, how have you connected up?
[21:41] <Laurenceb> cant remember sorry
[21:41] <Laurenceb> I used a data cannector off ebay
[21:42] <DanielRichman> One of you mentioned using a 50hz interrupt to talk to the radio.... Is it worth it if there isn't a 50hz interrupt immediately available without creating one (I dunno, 555 style :D). The arduino won't be doing -that- much so could just use sleeps/delays when we need to send a byte
[21:42] <DanielRichman> hallam, http://wiki.ukhas.org.uk/communication:protocol
[21:43] <hallam> DanielRichman: you should be able to create one with one of the timer peripherals built into the chip
[21:43] <hallam> all under software control
[21:43] <hallam> it tends to be neater / less buggy than doing it with delays
[21:44] <DanielRichman> hallam, groovy. Will look into it
[21:44] <Laurenceb> yeah, timer overflow interrupt
[21:44] <hallam> but you could do it with delays, I think I did my first RTTY transmitter that way
[21:44] <DanielRichman> lets see if the Arduino wiki has anything fun
[21:45] <sbasuita> DanielRichman, I really have no idea if the ericsson thing is going to work.
[21:45] <Laurenceb> if you use timer1, you can set a 16 bit top count
[21:45] <sbasuita> DanielRichman, we haven't even got a baud rate...
[21:45] <Laurenceb> 9600
[21:45] <DanielRichman> sbasuita, ssh, pessimist face. It will be fine
[21:45] <sbasuita> Laurenceb, do you still have that cable?
[21:45] <Laurenceb> 8n1
[21:45] <sbasuita> It would be nice to know which pins it was using
[21:45] <Laurenceb> fraid its at the bottom of the north sea
[21:46] <Laurenceb> along with the t68i
[21:46] <edmoore> not really
[21:46] <edmoore> it's on a sand bank
[21:46] <edmoore> in the wash
[21:46] <Laurenceb> yeah I exaggerated
[21:46] <edmoore> it is probably buried under sand by now though
[21:46] <edmoore> along with the treasure
[21:47] <Laurenceb> hmm apparently it is knows for cows to explode due to methane buildup, but the interwebs cannot provide me with video of this
[21:48] <hallam> Laurenceb: I think you've found a new direction for your graduate research career
[21:48] <Laurenceb> an experiment is called for
[21:49] <edmoore> if we take a cow on a helium balloon, do you think it will explode before the balloon?
[21:49] <DanielRichman> Laurenceb, you had a balloon go into the drink?
[21:49] <Laurenceb> yes
[21:50] <DanielRichman> unlucky
[21:51] <Laurenceb> http://www.youtube.com/watch?v=RiriqhUT_Wc&feature=related
[21:51] <Laurenceb> hmm they cheated
[21:54] <sbasuita> DanielRichman, doing some googling, it looks like a bunch of people are posting that 9-12 pin layout
[21:54] <sbasuita> DanielRichman, so feeling more confident now
[21:54] <sbasuita> : )
[21:54] <Laurenceb> IIRC its standard
[21:55] <Laurenceb> for ericssons
[21:55] <sbasuita> Laurenceb, oh good
[21:55] <sbasuita> Laurenceb, we intend to hack a usb cable
[21:55] <sbasuita> Laurenceb, since it uses the same pins
[21:57] <sbasuita> DanielRichman, actually, I might buy this now http://cgi.ebay.co.uk/Genuine-Sony-Ericsson-DCU-65-USB-Data-Cable-W800i%2fW810i_W0QQitemZ390026235206QQcmdZViewItem
[21:57] <sbasuita> What do you think?
[21:58] <DanielRichman> sbasuita, go go go!
[21:59] <DanielRichman> sbasuita, although - does it have all the pins?
[21:59] <sbasuita> DanielRichman, usb uses the same ones as seerial
[22:00] <DanielRichman> sbasuita, nonetheless, some connectors we've seen only had a few pins
[22:00] <DanielRichman> sbasuita, missing GND pin sometimes, etc.
[22:00] <sbasuita> DanielRichman, mm
[22:00] <sbasuita> DanielRichman, anyway gtg now
[22:01] <sbasuita> DanielRichman, will see you tomorrow
[22:01] sbasuita (n=sbasuita@unaffiliated/drebellion) left irc: "Leaving"
[22:02] edmoore (n=edmoore@chu-gw.churchillcambridge.co.uk) left irc:
[22:03] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) joined #highaltitude.
[22:17] <DanielRichman> Laurenceb, final question before I go... using timer2 to generate a 50hz for our radio won't interfere with pin11, which is part of the SPI. (Pin3 and pin11 are the PWM pins controlled by timer2). And if that's all ok, this thing looks like a very easy implementation: http://www.arduino.cc/playground/Code/FrequencyTimer2
[22:17] <Laurenceb> it wont
[22:17] <Laurenceb> but getting 50Hz would be tricky
[22:18] <Laurenceb> as 2 is 8 bits
[22:18] <Laurenceb> use timer1
[22:18] <DanielRichman> Ok. Afaik, timer0 is the only one that the Arduino relies on for millis(), so using timer2 or timer1 should be fine?
[22:19] <hallam> you don't have to use the pwm pins associated with a timer
[22:20] <DanielRichman> mmm. ok. Thanks - well I've gotta go now; so bye
[22:21] DanielRichman (n=DanielRi@89.243.213.125) left irc: "Leaving"
[22:21] rjharrison (n=rharriso@80.176.172.227) left irc:
[22:29] <Laurenceb> bbl
[22:29] <G8KHW> Fun with Heium and bin liners:- http://imagebin.org/43787 - about 120g of lift
[22:30] <G8KHW> Fun with Heium and bin liners and light sticks :- http://imagebin.org/43786
[22:32] Action: shellevil ponders superpressure.
[22:32] <shellevil> Prolly not
[22:36] <G8KHW> I must hook up a pressure guage and see if it will take
[22:37] <shellevil> Well...
[22:37] <shellevil> a light binbag'll hold what - 200Kg of stuff prolly if you distributed it _absolutely_ evenly
[22:38] <shellevil> actuall - 100Kg
[22:38] <shellevil> 1000N for about a metre of circumference, or 10mBish
[22:38] <shellevil> 3-5mB in reality wouldn't surprise me.
[22:39] <shellevil> But the leak rate at that'll be fierce
[22:42] Xenion (n=robert@p579FC8DE.dip.t-dialin.net) left irc: "Verlassend"
[23:10] aLeXBrEtOn (n=Alexande@client-86-25-182-53.bkl-bng-012.adsl.virginmedia.net) left #highaltitude.
[23:11] hallam (i=126f3681@gateway/web/ajax/mibbit.com/x-023a8e76e0e553bc) left irc: "http://www.mibbit.com ajax IRC Client"
[23:16] G8KHW (n=Steve@217.47.75.8) left irc: "Leaving"
[23:17] jcoxon (n=jcoxon@host81-152-142-254.range81-152.btcentralplus.com) joined #highaltitude.
[23:24] <jcoxon> evening
[23:28] <jcoxon> tis all quiet
[23:35] bfirsh (n=ben@scooby.firshman.co.uk) left irc:
[23:36] <Laurenceb> waste of helium
[23:40] <jcoxon> hmmmm someone has put up a page about the UKHAS standard
[23:40] <jcoxon> and got it slightly wrong
[23:40] Action: jcoxon fixes
[23:40] <icez> howdy jcoxon
[23:41] <jcoxon> hey icez
[23:48] <jcoxon> right i'm off been a long day
[23:48] <jcoxon> night all
[23:48] jcoxon (n=jcoxon@host81-152-142-254.range81-152.btcentralplus.com) left irc: "Leaving"
[23:59] Action: shellevil has had a long and shitty day too.
[00:00] --- Tue Mar 31 2009