highaltitude.log.20090605

[01:03] <SpeedEvil> I dunno how bad discontinuoties in the nozzle are
[01:14] <Laurenceb> yeah
[01:14] <Laurenceb> my avr programmer isnt working properly :-/
[01:14] <Laurenceb> cant reflash fusebits for some reason
[01:15] <Laurenceb> its odd - cant work out if its incompatible with avrdude or if its broken
[01:17] <Laurenceb> cant see how damage to the programmer would leave it unable to write fusebits
[01:17] <gordonjcp> are you meant to be able to reflash fusebits?
[01:18] <Laurenceb> yes
[01:18] <Laurenceb> Ive only used this programmer with windows before
[01:19] <Laurenceb> never tried reflashing fusebits from ubuntu
[01:19] <Laurenceb> but my windows installation is broken :(
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[01:37] Nick change: KingJ -> kingj
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[10:15] <Laurenceb> hi
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[12:20] <rjharrison_work> Hi fergusnoble
[12:20] <rjharrison_work> Are we going to see you on here a little more often now :)
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[13:01] <Laurenceb_> hmm if the new iphone has magnetometer then we're one step closer to an iphone imu
[13:02] <Laurenceb_> just the small matter of three gyros
[13:02] <SpeedEvil> camera = sun sensor
[13:03] <Laurenceb_> haha yeah
[13:03] <Laurenceb_> pity it sucks
[13:03] <Laurenceb_> need an android phone with the same specs
[13:04] <Laurenceb_> or openmoko
[13:04] <Laurenceb_> I was reading Sutton - it has some designs for ablative nozzels
[13:05] <Laurenceb_> theres an example using a graphite throught and phenolic/glass fibre nozzle
[13:07] <SpeedEvil> it's a good book
[13:08] <Laurenceb_> interesting problem: if you fire a ~2mm diameter projectile from a light gas gun, how can you track it to see if it broke 100Km ?
[13:11] <Laurenceb_> I was thinking 10GHz bistatic radar or an LED in the projectile
[13:13] <Laurenceb_> for the receiver you could use a
[13:13] <Laurenceb_> satellite TV LNB
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[13:14] <SpeedEvil> laser diode is as small as LED
[13:14] <SpeedEvil> and you can have a really narrowband filter
[13:16] <Laurenceb_> 2mm diameter?
[13:17] <SpeedEvil> A 1W LED with a 10 degree beam should be easily visible at 100Km
[13:17] <SpeedEvil> yes - you use the bare die, not a module
[13:17] <SpeedEvil> but battery is a worse problem
[13:18] <SpeedEvil> magnitude 4 star is 0.9nw/m^2 at earth
[13:18] <SpeedEvil> LED is 20% efficient or so
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[13:19] <SpeedEvil> so, to illuminate a 10^10m square patch, you'd need a pulse of 50W or so in
[13:20] <SpeedEvil> Much less for visible in binocs
[13:21] <SpeedEvil> I'd wonder about bistatic lidar
[13:21] <SpeedEvil> a few tens of watts of DVD or CDr lasers
[13:21] <SpeedEvil> narrowband filter, lock-in amp, avalanche photodiode
[13:21] <Laurenceb_> http://www.farnell.com/datasheets/315668.pdf <- almost
[13:23] <Laurenceb_> but how do you aim it?
[13:23] <SpeedEvil> you don't
[13:23] <Laurenceb_> ?
[13:23] <Laurenceb_> you'd need to illuminate a few hundered square Km
[13:23] <SpeedEvil> you have a wide beam, and rely on random spin to make it point at earth
[13:24] <Laurenceb_> oh on the projectile ok
[13:24] <SpeedEvil> then you have a sensitive detector
[13:24] <SpeedEvil> oh
[13:24] <Laurenceb_> yeah you can get cylindrical cells
[13:24] <Laurenceb_> but how they would withstand the acceleration
[13:24] <SpeedEvil> no you can't really
[13:24] <Laurenceb_> PIC10F would fit in a 2mm diameter
[13:25] <SpeedEvil> I've looked - the smallest that can do 1W out is about 10mm*18mm
[13:25] <SpeedEvil> I have a couple of those to make a silly torch
[13:25] <Laurenceb_> mini cylindrical cell - cap - laser
[13:25] <SpeedEvil> caps are a problem
[13:26] <SpeedEvil> unless you want _very_ short pulsewidths
[13:26] <Laurenceb_> it would be an option
[13:26] <SpeedEvil> At 2mm dia, I don't think you can do it actively
[13:27] <SpeedEvil> I'm unsure about a 2mm corner-cube
[13:27] <SpeedEvil> lasers on the ground, and a nice filtered scope on the ground
[13:27] <Laurenceb_> hmm yeah a corner cube would help a lot
[13:28] <Laurenceb_> over white projectile + laser on gnd
[13:29] <Laurenceb_> thats how retroreflective paint works
[13:29] <SpeedEvil> some orders of magnitude
[13:29] <Laurenceb_> but its a lot smaller that 2mm
[13:29] <SpeedEvil> it's not
[13:29] <Laurenceb_> yeah
[13:29] <Laurenceb_> oh its spheres?
[13:29] <SpeedEvil> yes
[13:29] <Laurenceb_> hmm
[13:29] <SpeedEvil> I looked at this for my 'virtual sky' project
[13:30] <SpeedEvil> (ceiling with a sky optically at infinity)
[13:30] <SpeedEvil> RI 2 or so balls in 0.5-2mm or so are available in large drums.
[13:31] <SpeedEvil> You put them into a white matrix, clean the front a bit to expose them, and they are reteroreflectors
[13:31] <SpeedEvil> Depending on the diameter, roundness, and exact refractive index, the cone diameter varies
[13:33] <Laurenceb_> ok
[13:33] <Laurenceb_> hmm wonder what camer you need
[13:33] <Laurenceb_> guess a fairly standard canmera might work...?
[13:33] <Laurenceb_> as you want a high frame rate really
[13:33] <SpeedEvil> For above project - sort balls by size - photoexpose the back of them to make a pattern in various resists and stuff - and then illuminate from the back.
[13:33] <Laurenceb_> wonder how well webcams with IR filter removed would work
[13:33] <SpeedEvil> Not really - you want one with low noise.
[13:33] <SpeedEvil> which is expensive
[13:33] <SpeedEvil> webcams have noises of (IIRC) several hundred photons
[13:33] <Laurenceb_> how much lower is the noise on the low noise ones?
[13:33] <SpeedEvil> photoelectrons
[13:34] <Laurenceb_> ouch
[13:34] <SpeedEvil> 2-3 photoelectrons is readable on the best cooled
[13:34] <Laurenceb_> however... with retroreflectors
[13:34] <Laurenceb_> and a pulsed high power laser
[13:35] <Laurenceb_> then time gating on the frames
[13:35] <SpeedEvil> Say a 100m beam - 1mw/m^2 is probably achievable at moderate cost on orbit
[13:35] <SpeedEvil> that's - call it 10^-9W coming back from a 2mm reteroreflector
[13:36] <Laurenceb_> yeah thats what I get
[13:36] <SpeedEvil> 2mm will have a divergance of what - call it a milliradian?
[13:36] <Laurenceb_> yeah
[13:37] <Laurenceb_> 10^-15W into scope say
[13:37] <SpeedEvil> At 200Km, that's 200m spot round the laser
[13:38] <SpeedEvil> Or 10^-14 or so/m^2 - yeah - that's probably sane
[13:38] Action: SpeedEvil fails on remembering the energy of a red photon
[13:38] <Laurenceb_> so about 1000 photons/sec
[13:39] <SpeedEvil> 3*10^-19J
[13:40] <SpeedEvil> Maybe a bit more
[13:40] <SpeedEvil> but that looks healthy
[13:40] <SpeedEvil> to the point that you probably want to up the laser power some and cheap out a bit on the scope
[13:40] <SpeedEvil> Or widen the beam
[13:41] <SpeedEvil> I do wonder about backscatter though
[13:41] <SpeedEvil> gating at that speed isn't trivial
[13:42] <Laurenceb_> I wonder if going for a avalanche photodiode and crazy time gating would do anything
[13:42] <SpeedEvil> (to pulse the beam at C/100Km
[13:42] <SpeedEvil> hmm
[13:42] <Laurenceb_> that osram datasheet says 80ns is possible
[13:43] <Laurenceb_> and it has caps and fet builting
[13:43] <SpeedEvil> There are scary fast maxim parts
[13:43] <SpeedEvil> which are made for this - bare die
[13:44] <Laurenceb_> its not thats scary - a few clocks on a uC
[13:44] <Laurenceb_> twiddle a gpio to drive it
[13:44] <SpeedEvil> I mean fast recievers
[13:44] <SpeedEvil> >1Gbps
[13:44] <Laurenceb_> then a flash adc and grab through a port
[13:45] <Laurenceb_> only need a few Msps
[13:45] <SpeedEvil> Oh - for much of the above I was assuming an imaging detector - ccd - hence gating
[13:49] <Laurenceb_> aiming is an issue
[13:50] <Laurenceb_> maybe it you have an imu on the balloon, then fire with the telescope downrange
[13:50] <Laurenceb_> so the telescope just points up at some angle such that the arc of the projectile intersects the beam at two points
[13:54] <Laurenceb_> unfortunately you arent going to get many photons
[13:54] <SpeedEvil> should get a streak
[13:54] <SpeedEvil> if you have a gated ccd
[13:56] <Laurenceb_> yeah
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[14:08] <Laurenceb> http://www.starlight-xpress.co.uk/products.htm
[14:08] <Laurenceb> ^ yum
[14:13] <SpeedEvil> some nice 'lower end' stuff there
[14:13] <SpeedEvil> (compared to the pro stuff)
[14:13] <Laurenceb> hmm one of those + a ~10cm scope + an electronic mount
[14:13] <Laurenceb> and it would be pissible I think
[14:13] <Laurenceb> *possible
[14:14] <Laurenceb> would need an accurate IMU on the firing platform
[14:14] <Laurenceb> < 1 degree error
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[14:16] <Laurenceb> actually... if you added leds on the hab
[14:16] <Laurenceb> you could locate the hab
[14:16] <Laurenceb> then with some very fast image processing, calculate the apogee position from the frame showing LGG firing
[14:17] <Laurenceb> and electronically pan the scope to grab a frame of apogee
[14:18] <Laurenceb> you've got a minute or so
[14:23] <Laurenceb> there should be time to do several intermediate frames
[14:23] <Laurenceb> problem is it doesnt give range
[14:25] <SpeedEvil> boresighted star-tracker
[14:25] <SpeedEvil> on the balloon
[14:26] <SpeedEvil> as well as speed gat
[14:26] <SpeedEvil> e
[14:26] <Laurenceb> a bit ott
[14:26] <Laurenceb> hmm
[14:27] <Laurenceb> IMO easier to keep as much kit as poss on the gnd
[14:27] <SpeedEvil> Well - practically
[14:27] <SpeedEvil> it's a little camera
[14:27] <SpeedEvil> My 50 quid surveilance camera will almost do for the star-tracker - at video rates
[14:27] <SpeedEvil> if you pick the right time for bright stars to be in view
[14:28] <SpeedEvil> also
[14:28] <SpeedEvil> the 200 quid or whatever for a star-tracker is not going to be the expensive bit
[14:29] <Laurenceb> telescope mount is expensive yes
[14:29] <SpeedEvil> telescope mount?
[14:30] <SpeedEvil> I was more thinking of a 45 degree or so FOV fast lens, and a 1/3" CCD or something.
[14:32] <Laurenceb> realisitically youll have to track the projectile with the scope
[14:34] <Laurenceb> stick a laser + diffuser on the bottom of the hab
[14:34] <Laurenceb> so you can aim the scope to start with
[14:38] <Laurenceb> hmm maybe you could reconstruct the trajectory with teh gps fix from the hab at gun firing + the size of the streaks left on the CCD by the flashing laser
[14:38] <SpeedEvil> I mean - with the gate and the boresight star-tracker - your unceerainty is due to the inaccuracy of the gun plus the error on the speed gate
[14:38] <Laurenceb> I'm not suire if you can gate the CCD accurately enough...
[14:39] <SpeedEvil> No
[14:39] <SpeedEvil> Sorry
[14:39] <SpeedEvil> I mean - two photodiodes/LEDs on the ooutput of the gun spaced at 10cm
[14:39] <Laurenceb> oh right
[14:40] <Laurenceb> but you can get the velocity at firing from the gps position and a single frame from the ground
[14:40] <Laurenceb> providing backscatter can be avoided
[14:40] <SpeedEvil> well - yes
[14:41] <SpeedEvil> but on the gun - you have a SNR of 10% or so easily - with the bullet blocking 10% of a 10mm beam
[14:41] <Laurenceb> ideally you want to fire the laser through the telescope
[14:42] <SpeedEvil> umm - why?
[14:42] <SpeedEvil> oh
[14:42] Action: SpeedEvil misread that as 'gun through the telescope'
[14:43] <SpeedEvil> you can do that - but it _really_ complicates the optic
[14:43] <SpeedEvil> s
[14:44] <Laurenceb> main thing is gaiting
[14:44] <Laurenceb> *gating
[14:46] Action: SpeedEvil ponders sponsorship by the ministry of silly walks
[14:57] <Laurenceb> hmm I think you need two ganged scopes a few hundered meters apart
[14:57] <Laurenceb> on electronic mounts
[14:57] <Laurenceb> you gang them first using a guide star, then one is you camera, one the laser
[14:58] <SpeedEvil> If you are doing that for the balloon - you have no problem at all wirth photons
[14:58] <SpeedEvil> I was assuming that you were trying to track it actually in orbit
[14:58] <Laurenceb> you hab has a diffused laser on the bottom, so you can aim at the hab
[14:58] <SpeedEvil> A 10m - or even smaller beam is quite practical for the hab
[14:58] <SpeedEvil> and 1W blue LEDs are just fine
[14:59] <SpeedEvil> (50% efficiency)
[14:59] <Laurenceb> no, just for a LGG on a HAB, firing up to a 100Km or so
[14:59] <Laurenceb> what?!
[14:59] <SpeedEvil> (well - for the released in a couple of months ones)
[14:59] <Laurenceb> you want to do this from the ground
[14:59] <SpeedEvil> (for the HAB illuminator)
[14:59] <SpeedEvil> I mean - pointing at the HAB
[14:59] <SpeedEvil> if you have a scope on the ground with a laser
[14:59] <Laurenceb> and track the retroreflectors from ~200Km line of sight
[15:00] <Laurenceb> your not going to do that with LEDs
[15:05] <Laurenceb> I think it may be possible to reconstruct the trajectory in 3D... if you have the position of the HAB at gun firing
[15:05] <Laurenceb> and of the ground station
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[15:09] <Laurenceb> pity you need two steered scopes - its going to be expensive
[15:18] <Laurenceb> http://www.meade.com/etx_premier/index.html
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[15:36] <SpeedEvil> not very
[15:36] <SpeedEvil> steered scopes are not particularly expensive on ebay
[15:42] <jcoxon> afternoon all
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[15:44] <Laurenceb> stupid mibbit
[15:49] <Laurenceb> SpeedEvil: two meade telescopes isnt a stupid amount
[15:49] <Laurenceb> I'm sure you can get cheaper than meade tho
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[16:03] <Laurenceb> I just got chucked off freenode
[16:03] <SpeedEvil> ?
[16:03] <SpeedEvil> oh
[16:03] <SpeedEvil> that's odd
[16:03] <SpeedEvil> so you did
[16:03] <Laurenceb> "you may not contact freenode, this message has been sent in accordance with freenode policy"
[16:03] <SpeedEvil> Haveyou been doing anything naughty?
[16:03] <Laurenceb> but it let me log back on
[16:03] <Laurenceb> no, I was just logged in here
[16:03] <SpeedEvil> ah
[16:03] <SpeedEvil> maybe another mibbit user
[16:04] <Laurenceb> tho the connection here is a bit dodgy and I was using mibbit
[16:04] <jcoxon> Laurenceb, they are onto you!
[16:04] <Laurenceb> hehe
[16:04] <Laurenceb> not any more apparently
[16:06] Action: SpeedEvil coats Laurenceb in 4mm of brie to distract them.
[16:06] <SpeedEvil> How many terrorists have you seen coated in cheese?
[16:07] <jcoxon> SpeedEvil, its a good point
[16:08] <Laurenceb> cheese ablation could protect you from nuclear blast
[16:08] <jcoxon> i have to admit none
[16:08] <SpeedEvil> Actually - bacon would be better.
[16:08] <SpeedEvil> Plus - A tasty treat for after.
[16:15] Action: jcoxon just got his order from rapid
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[16:22] <sbasuita> So any launches this weekend?
[16:23] Action: SpeedEvil haz hail.
[16:24] <Laurenceb> jcoxon: what did you get?
[16:27] <jcoxon> avrisp mkII
[16:27] <jcoxon> and so bits and bobs
[16:28] <Laurenceb> I have avr programmer woes :-/
[16:28] <Laurenceb> cant reprogram fusebits
[16:29] <Laurenceb> which means I cant get the UM12 test hab working
[16:29] <jcoxon> oh
[16:29] <jcoxon> thats not good
[16:29] <jcoxon> which is your programmer?
[16:29] <Laurenceb> I think it may be that my programmer is incompatible with avrdude
[16:30] <Laurenceb> http://shop.myavr.com/index.php?sp=article.sp.php&artID=42
[16:30] <Laurenceb> I need to fix windows
[16:30] <Laurenceb> then I can try it with avr-osp2
[16:30] <Laurenceb> I know it used to work with that
[16:30] <Laurenceb> its odd as I can read fusebits and read/write flash
[16:32] <Laurenceb> avrisp mkll is serial?
[16:33] <jcoxon> no its usb
[16:34] <Laurenceb> oh cool
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[16:37] <Laurenceb> can it power the target board?
[16:38] <Laurenceb> bah hes gone
[16:39] <rjharrison_work> Laurenceb: was james on his comupter or iphone?
[16:39] <Laurenceb> dunno
[16:39] <Laurenceb> gtg, cya
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[16:40] <sbasuita> n=jcoxon@host86-163-199-83.range86-163.btcentralplus.com
[16:40] <sbasuita> so probably some wifi
[16:40] <sbasuita> (as opposed to 3g)
[16:41] <rjharrison_work> True sbasuita
[16:41] <rjharrison_work> I thought that afterwards
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[18:33] <mc-> fergusnoble, are you planning to use the balloon fabric we got last year?
[18:34] <fergusnoble> yeah we are using some of it
[18:34] <fergusnoble> doubt we will get close to using it all though do you need some?
[18:34] <mc-> I don't think I can build a zp in my garage
[18:35] <mc-> if I came to Camb one day, could I borrow your machine?
[18:36] <fergusnoble> we can proably arrange something
[18:36] <mc-> wanted to build a small tube ZP
[18:36] <mc-> or whatever is quickest to build
[18:36] <fergusnoble> although its not a one mand job unfortunately and takes a bit of practice
[18:36] <fergusnoble> the machine is a bit tempramental
[18:37] <mc-> would it take long to build a zp to lift 100g?
[18:37] <SpeedEvil> not really
[18:37] <SpeedEvil> binbags and a heat-sealer will do it.
[18:37] <SpeedEvil> oh
[18:37] <fergusnoble> on the machine it would take half a day, but you could make one to lift 3kg in the same amount of time
[18:37] <SpeedEvil> you mean 100g at altitude
[18:38] <fergusnoble> the time is taken up reseting the machine to do another seam
[18:38] <mc-> perhaps I should experiment with a heat sealer first
[18:38] <fergusnoble> once its going you may as well run through a long length, it takes like a minute to weld 20 odd meters
[18:39] <fergusnoble> yeah, we have some heat sealers we made with 40cm jaws
[18:39] <SpeedEvil> mc-: there are stupid heat-sealers that are interersting
[18:39] <fergusnoble> im sure you could borrow one
[18:39] <fergusnoble> brb
[18:39] <mc-> 40cm sounds good, could make a balloon with 80cm seams
[18:40] <mc-> a 80cm high tube might carry 100g
[18:40] <SpeedEvil> http://cgi.ebay.co.uk/NEW-The-Amazhttp://cgi.ebay.co.uk/NEW-The-Amazing-POLYBONDER-Heat-Handy-Seal-Bag-Sealer_W0QQitemZ380126218991QQcmdZViewItemQQptZUK_HomeGarden_Kitchen_FoodStorage_GL?hash=item588149caef&_trksid=p3286.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1688|240%3A1318|301%3A1|293%3A1|294%3A50ing-POLYBONDER-Heat-Handy-Seal-Bag-Sealer_W0QQitemZ380126218991QQcmdZViewItemQQptZUK_HomeGarden_Kitchen_FoodStorage_GL?hash=item588149caef&_tr
[18:40] <SpeedEvil> meh
[18:41] <SpeedEvil> http://cgi.ebay.co.uk/NEW-The-Amazing-POLYBONDER-Heat-Handy-Seal-Bag-Sealer_W0QQitemZ380126218991QQcmdZViewItemQQptZUK_HomeGarden_Kitchen_FoodStorage_GL?hash=item588149caef&_trksid=p3286.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1688|240%3A1318|301%3A1|293%3A1|294%3A50
[18:41] <SpeedEvil> sorry
[18:41] <SpeedEvil> stupid slow-responding paste
[18:42] <mc-> that ebay items seems to be able to continously weld, correct?
[18:42] <SpeedEvil> Focus had/have soe 3m*4m*7.5um 'heavy duty' (lol) polythene tarps
[18:42] <SpeedEvil> yes
[18:43] <SpeedEvil> It's - for thin stuff - quite OK
[18:44] <mc-> might be easiest to get the ebay item, rather than drive to Camb
[18:44] <mc-> how do you put in the filling nozzle?
[18:44] <SpeedEvil> They vary - I've not got that exact model - nor have I tried it for >1m
[18:45] <SpeedEvil> I was just going for the simple option of a thick straw, with string and silicone round it
[18:45] <mc-> McDonald's straw?
[18:45] <SpeedEvil> something similar
[18:45] <mc-> will be slow to fill?
[18:46] <SpeedEvil> probably - I had this planned to use natural gas.
[18:46] <mc-> off to ebay, time to buy
[18:50] <mc-> bought it
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[20:14] <rjharrison> Evening all
[20:15] <sbasuita> evening
[20:15] <sbasuita> blender has stolen my cpu
[20:16] <sbasuita> probably my fault for expecting it to do ray tracing with ridiculous numbers of samples and vertices ;P
[20:16] <rjharrison> ar
[20:16] <rjharrison> opps
[20:16] <rjharrison> oh dear
[20:16] <rjharrison> I have been playing with pyro cutdown
[20:16] <sbasuita> pyro?
[20:16] <rjharrison> Need to leave the resin to set for longer :)
[20:17] <rjharrison> Electric match and smokeless powder in a plastic tube
[20:17] <sbasuita> ah
[20:18] <sbasuita> wikipedia has a more elaborate explanation
[20:18] <sbasuita> .wik Mineral-insulated copper-clad cable
[20:18] <herabot> "Mineral-insulated copper-clad cable is a variety of electrical cable made from copper conductors inside a copper sheath, insulated by inorganic magnesium oxide powder." - http://en.wikipedia.org/wiki/Mineral-insulated_copper-clad_cable
[20:18] <sbasuita> "also known as pyro"
[20:18] <sbasuita> ; P
[20:18] Action: sbasuita cancels the render
[20:19] <rjharrison> http://en.wikipedia.org/wiki/Pyrotechnics
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[21:25] Action: SpeedEvil ponders organic magnesium oxide powder.
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[22:00] <rjharrison> ping fergusnoble
[22:00] <fergusnoble> hi rjharrison
[22:00] <rjharrison> Quick question
[22:00] <fergusnoble> shoot
[22:00] <rjharrison> If I want the bearing between 2 gps coords
[22:01] <rjharrison> Do I want the great circle one or the true course
[22:01] <rjharrison> To display on the stats papge
[22:01] <rjharrison> I have dist from launch
[22:01] <fergusnoble> hmm, i dont know
[22:01] <rjharrison> just struggeling to get bearing
[22:01] <fergusnoble> are you looking on aviation formulary?
[22:02] <rjharrison> hehe Yep
[22:02] <rjharrison> Can you see that
[22:02] <rjharrison> http://williams.best.vwh.net/avform.htm#Implement
[22:02] <rjharrison> I'll go for great circle
[22:03] <fergusnoble> ok it might be a true / magnetic north thing?
[22:03] <rjharrison> I doubt anyone other than the camb crew are likly to notice if it's one or the other
[22:04] <fergusnoble> hehe
[22:05] <fergusnoble> i have no idea what the difference is
[22:05] <fergusnoble> henry knows a lot aout navigation though, he might know
[22:05] <fergusnoble> what are you writing?
[22:06] <rjharrison> Ok
[22:06] <rjharrison> fergusnoble: http://www.robertharrison.org/mobile.php?r=1242581128
[22:06] <rjharrison> Just the last line I'm struggeling to get the
[22:06] <rjharrison> deg right
[22:06] <rjharrison> I'm in radians
[22:09] <fergusnoble> yeah, also beware, i think the aviation formulary had a different sign convention for longitude
[22:09] <rjharrison> That might explain it
[22:09] <fergusnoble> the badger ground software outputs headings with east and west reversed at the moment because of that i think :(
[22:10] <rjharrison> Humph bloody math
[22:10] <rjharrison> Been a whiile
[22:10] <fergusnoble> which reminds me i reall should fix that
[22:10] <fergusnoble> yeah the great circle stuff is a pain to get your head around
[22:11] Action: SpeedEvil draws circles on rjharrisons head.
[22:19] <rjharrison> fergusnoble: Soory put the kids to bed...
[22:19] <rjharrison> While you are at it you could chuck the xor checksum in
[22:23] <fergusnoble> yup, will do
[22:23] <fergusnoble> working on the landing prediction atm but will do it after that
[23:02] Action: sbasuita adds real-time landing prediction on the tracker to his wishlist
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[23:27] <fergusnoble> sbasuita: its on the way :)
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[23:55] <rjharrison> fergusnoble: Cool rtlp will be cool. What data can we send in other than current position & alt?
[23:55] <rjharrison> ie Can we post prior ascent data to influence the model on the way down?
[23:56] <fergusnoble> you give it current posn and alt and also the ascent rate
[23:57] <fergusnoble> its up to the tracker to estimate the ascent rate from the data its got
[23:57] <fergusnoble> you can also give it a drag coefficient for the way down which you can also estimate from the data if you want
[23:58] <rjharrison> Cool you will have to let me know how to calc that coeff
[23:58] <fergusnoble> or just use a pre calculated value based on the parachute size
[23:58] <rjharrison> True
[23:58] <fergusnoble> yup, will write up docs on how to use it
[23:58] <rjharrison> Cool
[23:58] <rjharrison> That will be emense esp if we c an overlay the kml onto the tracker
[23:59] <rjharrison> right nights
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[23:59] <fergusnoble> ok, gdnight
[00:00] --- Sat Jun 6 2009