highaltitude.log.20070102

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[12:11] <LaurenceB> got the emails adout helium
[12:11] <LaurenceB> the t cylinder will lift about 3KG
[12:12] <LaurenceB> ie total lift 4 kg, with 1kg spare
[12:13] <LaurenceB> oh okay other way round
[12:13] <LaurenceB> n20>T
[12:16] <LaurenceB> n20 ---> approx 4.5kg payload capacity
[12:19] <LaurenceB> want to know what rocketboy thinks about an extra payload...
[12:20] <LaurenceB> okay I'm off cya
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[12:58] <defy> hows it going guys
[13:03] <jcoxon> hey defy
[13:04] <defy> happy new year and all that :)
[13:04] <jcoxon> and to you as well
[13:11] <jcoxon> just been reading the website of these guys who did a transatlantic flight with a model plane
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[13:16] Action: jcoxon is waiting for his rechargable batteries to charge so he can test peg IV outside
[13:17] <defy> crazy, solar powered?
[13:18] <jcoxon> the transatlantic flight? no coleman stove/lantern fuel
[13:18] <jcoxon> http://tam.plannet21.com/
[13:18] <jcoxon> i'm really interested in the legalities of it
[13:19] <jcoxon> as in it would be a real challenge to say get an amateur balloon to cross the atlantic
[13:22] <defy> thats crazy
[13:23] <jcoxon> v. cool :-D
[13:25] <jcoxon> launch a balloon from the UK to mainland europe
[13:26] <jcoxon> link up with a european balloon group (if they exist)
[13:26] <Weiss> you might have an entertaining time getting the wind to cooperate
[13:27] <jcoxon> there is that
[13:27] <Weiss> onshore/offshore wind etc
[13:27] <jcoxon> well you'd need to climb early and get into the jetstream
[13:28] <jcoxon> let that carry you over - cut the balloon and then freefall through the winds
[13:28] <jcoxon> open parachute a bit lower
[13:28] <jcoxon> and land at a designated spot
[13:28] <Weiss> being able to pre-program the landing site would be neat
[13:29] <jcoxon> yeah - some peoples landing site predictions are quite accurate
[13:29] <jcoxon> as you ascend you use your speed as a measure of the wind speed at that level
[13:29] <jcoxon> and then decide when to cut to get to the landing spot
[13:30] <jcoxon> using the data you got
[13:31] <LaurenceB> I've heard of this before
[13:31] <LaurenceB> its pretty cool!
[13:32] <jcoxon> henry has implimented into his trackers
[13:32] <jcoxon> but i'm not sure its turned on
[13:32] <jcoxon> and also rocketboy using old data has software which is pretty good at predicting a landing spot
[13:32] <LaurenceB> I was thinking about long duration balloon a while ago
[13:32] <LaurenceB> solar hot air balloons look promising
[13:33] <LaurenceB> they can fly at night from the ir flux
[13:33] <LaurenceB> I just dont have a large barn to assemble one in
[13:34] <LaurenceB> http://perso.orange.fr/ballonsolaire/en-index.htm
[13:35] <LaurenceB> http://www.flymetothemoon.com.au/homebuilding/solar.htm
[13:36] <jcoxon> how much space is needed?
[13:37] <LaurenceB> not sure, it would be very payload dependant
[13:37] <LaurenceB> you would want the payload as light as poss
[13:37] <jcoxon> what heights would be achieved?
[13:37] <LaurenceB> and then build the envelope to size
[13:38] <LaurenceB> it would be filled with helium to start off, so first day up to 40km
[13:38] <LaurenceB> would need to buy a large roll of lastic film from a wholesaler
[13:38] <LaurenceB> -plastic
[13:38] <jcoxon> basically making a mylar balloon
[13:39] <jcoxon> but it being black we use radiation for additional lift
[13:39] <LaurenceB> and make a motorised plastic welding machine, poss modify a sewing machine
[13:39] <LaurenceB> the main envelope would be transparent
[13:40] <jcoxon> oh right
[13:40] <jcoxon> what sort of size would this be?
[13:40] <LaurenceB> and strenched across the middle there would be mylar
[13:40] <jcoxon> i'm just thinking on the issues - i've launched some big balloons before
[13:40] <LaurenceB> with black plastic film on the bottom
[13:41] <LaurenceB> no sure on size
[13:41] <LaurenceB> did loads of calculations a while back
[13:41] <LaurenceB> http://www.cosis.net/abstracts/COSPAR02/03045/COSPAR02-A-03045.pdf
[13:41] <jcoxon> hmm ho - its a nice idea
[13:42] <jcoxon> but i worry about safety etc
[13:42] <jcoxon> of it landing
[13:42] <LaurenceB> a french group did a launch with one that circumnavigated the glode twice!
[13:42] <LaurenceB> frew for 4 weeks
[13:42] <LaurenceB> -flew
[13:42] <jcoxon> thats what i worry about
[13:43] <LaurenceB> it would need to be solar powered with sat phone
[13:43] <jcoxon> there is a CNES MIR balloon flight next year
[13:43] <LaurenceB> yes it was CNES who did the 4 week flight
[13:43] <jcoxon> which is pretty cool
[13:44] <jcoxon> oh i worked with them in africa
[13:44] <LaurenceB> their balloons are mylar on the top
[13:44] <LaurenceB> transparent below
[13:44] <jcoxon> though we didn't launch any MIR balloons
[13:44] <LaurenceB> only reason being they can make them easily with their existing equiptment
[13:45] <LaurenceB> a totally transparent envelope with mylar that is black on the bottom across the middle would be better
[13:45] <LaurenceB> bottom of the mylar would absorb the ir top would radiate little
[13:46] <LaurenceB> the balloon relied solely on ir flux from the earth
[13:46] <LaurenceB> not solar
[13:46] <jcoxon> what we need is a desert
[13:46] <LaurenceB> only drops about 7km at night
[13:46] <jcoxon> for flights and test
[13:46] <jcoxon> s
[13:47] <LaurenceB> it will work anywhere except northern regions in winter, the poles and tropical thunderstorms
[13:47] <LaurenceB> if designed correctly
[13:47] <LaurenceB> so summer in uk would work
[13:48] <LaurenceB> especially if we used the jet strem to send it to central europe
[13:48] <LaurenceB> while it still had its helium fill
[13:48] <jcoxon> the legalities and organsation would scare me
[13:49] <LaurenceB> yes... sat phone would solve the communication issues
[13:49] <LaurenceB> doubt you could use a gumstix as it would have to be solar powred
[13:50] <LaurenceB> but I think the envelope is buildable
[13:50] <LaurenceB> with a barn a motorised heat sealing machine and a few people it would only take a few days
[13:50] <jcoxon> + cooperation of countries we fly into
[13:51] <LaurenceB> they would have to be organised to avoid sealing the wrong bits together lol
[13:51] <jcoxon> ever thought about a valve in a totex balloon
[13:51] <jcoxon> instead of tying it off we plug it
[13:51] <LaurenceB> yes, a lot easier!
[13:51] <jcoxon> and the the plug can have a whole which opens and closes
[13:52] <jcoxon> perhaps a screw mechanism to reduce buoyancy to stop us reaching burst height
[13:52] <LaurenceB> use a servo
[13:53] <jcoxon> damn gpios on this router
[13:53] <LaurenceB> the balloon would be fixed onto a plastic tube, similar to the inflation device, and the payload would be on one end of this
[13:54] <jcoxon> yup
[13:54] <LaurenceB> there would be a t junction, where the helium was connected to inflate the balloon
[13:54] <jcoxon> actually wouldn't be too dificult
[13:54] <jcoxon> hehe could use the vented helium as propolsion
[13:54] <LaurenceB> the third bit of pipe would have the payload on it, along with valve
[13:54] <LaurenceB> one an end cap
[13:54] <jcoxon> actually i thought through this - could use a second balloon with just air which could be vented to move us around
[13:55] <LaurenceB> drill a hole, have a rubber bung than is pushed up by the servo
[13:55] <LaurenceB> rubber would have to be flexible at low temp
[13:56] <LaurenceB> helium filling input could be tricky
[13:56] <LaurenceB> ***- way better idea, use plastic 15mm plumbing fittiing
[13:57] <LaurenceB> then can have a solenoid valve
[13:57] <LaurenceB> and cut off valve for filling
[13:57] <jcoxon> could be very interesting
[13:57] <LaurenceB> one end has 40mm waste pipe fixed on for balloon
[13:57] <LaurenceB> simple
[13:57] <LaurenceB> - off to b&Q
[13:58] <LaurenceB> problem, what is balloon pops
[13:58] <LaurenceB> where does parachute go?
[13:58] <jcoxon> tube deply the parachute
[13:58] <jcoxon> see the UKHAS glider page on the wiki
[13:58] <LaurenceB> oh rocketboys invention
[13:59] <LaurenceB> is that pyrotechnically powered?
[13:59] <jcoxon> yup
[13:59] <jcoxon> loke a rocket
[13:59] <jcoxon> like*
[13:59] <LaurenceB> okay have that on side of payload
[13:59] <LaurenceB> with code to fire it if payload is falling like mad
[14:00] <jcoxon> yup
[14:00] <LaurenceB> and to operate the solenoid valve if we're above a certain target ascent rate for that altitude
[14:01] <jcoxon> exactly
[14:01] <LaurenceB> ie target ascent rate=0 at say 22km
[14:01] <jcoxon> could gently vent the gas to allow us to drift down
[14:02] <LaurenceB> would do a rough estimate of how fast we can vent helium, and how fast this would change out ascent rate
[14:02] <jcoxon> have to launch in high pressure zone to stop us speeding away
[14:02] <LaurenceB> the code would see if we can vent gas fast enough in the future to avoid overshooting and popping the balloon
[14:03] <LaurenceB> if no then open the valve
[14:03] <LaurenceB> if yes close it
[14:04] <LaurenceB> when we want to come down, open valve until were going down at say 5m/s
[14:05] <jcoxon> yeah
[14:05] <jcoxon> my worry is actually how far we'll travel
[14:05] <jcoxon> we work in such a small zone
[14:05] <LaurenceB> use previous data on ascent rate and fill balloon with air to calculate the constants well need for the code
[14:05] <jcoxon> i know its a long duration balloon
[14:05] <jcoxon> but we don't really have the distance
[14:06] <LaurenceB> probably best aiming for a landing outside of the uk
[14:06] <LaurenceB> to avoid ending up in the sea by trying to keep the flight in the country
[14:07] <jcoxon> hmmm
[14:07] <LaurenceB> launch when theres a bit of jet stream to end up in holland
[14:08] <jcoxon> but then we have all the issues of landing in holland
[14:08] <LaurenceB> channle tunnel
[14:08] <LaurenceB> send someone there to get it beforehand
[14:08] <jcoxon> air traffic control?
[14:08] <LaurenceB> have to be sure phone will work
[14:09] <jcoxon> remember our caa permission is intheory for a range of 120km
[14:09] <jcoxon> or maybe 100km
[14:09] <LaurenceB> hmmm
[14:09] <jcoxon> i can't remember
[14:10] <LaurenceB> we could get in touch with them and ask obout it
[14:10] <jcoxon> yeah
[14:11] <LaurenceB> i'm sure the payload wont be too dangerous
[14:11] <LaurenceB> solenoid valves maybe
[14:11] <LaurenceB> if it got suched into a jet ending
[14:11] <LaurenceB> - sucked, engine
[14:12] <LaurenceB> but they are ment to mithstand large birds
[14:12] <jcoxon> its a big sky
[14:13] <LaurenceB> those model plane people fly across the atlantic
[14:13] <LaurenceB> if we explained the payload to them they probably wouldn't mind
[14:16] <LaurenceB> hmmm I need to know if I'm building a payload for saturday so I can get it done today
[14:18] <LaurenceB> -sunday
[14:22] <LaurenceB> alternatively we could lauch a solar balloon i.e. direct solar heating in the summer, that would be quite long duration and we should be able to keep it in the uk
[14:22] <jcoxon> all good ideas :-)
[14:22] <jcoxon> will have to see - i'm going to be away for about a month this summer
[14:24] <LaurenceB> building a solar balloon would be an interesting project, I've tried before, using wheely bin liner, and made something that would just take off
[14:25] <jcoxon> yeah
[14:25] <LaurenceB> so put a bit more work into it and it should be possible to lift a payload
[14:25] <jcoxon> i always forget how far we've come along in the past year and a bit
[14:26] <jcoxon> thats how long i've been doing this for now
[14:26] <LaurenceB> I built a wheely bin liner with meths burner and wireless video camera
[14:26] <LaurenceB> last year
[14:26] <LaurenceB> it flew but I broke the long range 24ghz transmitter :(
[14:27] <LaurenceB> -2.4
[14:28] <LaurenceB> I flew it with christmas lights on instead!
[14:28] <jcoxon> right i'll bbl
[14:29] <LaurenceB> http://www.ashbournenewstelegraph.co.uk/detail.asp?cat=General%20News&id=4414068
[14:30] <LaurenceB> okay I'm going to build a payload for sunday, hopefully it will be poss to launch it
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[14:56] <LaurenceB> http://perso.orange.fr/ballonsolaire/en-historique3.htm
[14:56] <jcoxon> :-)
[14:57] <jcoxon> not sure that we have the resources that CNES have :-D
[15:01] <LaurenceB> need to find my previous calculations, but think I found that it was possible, about 20m long envelope or something
[15:02] <LaurenceB> envelope would be almost all the weight
[15:02] <LaurenceB> payload only a couple of kg at most
[15:03] <jcoxon> we need an aim
[15:03] <jcoxon> as in a reason for the construction
[15:03] <jcoxon> apart from cause we can
[15:05] <LaurenceB> http://perso.orange.fr/ballonsolaire/en-photos.htm
[15:07] <LaurenceB> http://perso.orange.fr/ballonsolaire/ballon-08-06-2000.htm
[15:08] <jcoxon> hehe - cause we can :-p
[15:09] <LaurenceB> have you seen the link I posted earlier: http://www.ashbournenewstelegraph.co.uk/detail.asp?cat=General%20News&id=4414068
[15:09] <jcoxon> yup
[15:09] <jcoxon> was that you?
[15:09] <LaurenceB> yes
[15:10] <LaurenceB> okay i'm off to work on my payload for sunday
[15:11] <LaurenceB> cya then
[15:11] <jcoxon> cya
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[17:56] <jcoxon> hey mc-
[17:56] <jcoxon> hey icez
[17:56] <icez> hey
[17:58] <jcoxon> know anything about 2p2t relays?
[17:59] <mc-> hey jcoxon, just sent you an email
[17:59] <mc-> what do you want to know about relays
[17:59] <mc-> 2p2t = 2 pole 2 throw
[18:00] <jcoxon> right well i'm having issues with my damn camera
[18:00] <jcoxon> basically its one of those that requires half depression to focus
[18:00] <mc-> I remember from before
[18:00] <jcoxon> and the gpios on the router don't actually drop down to 0 - as the control dual colour leds
[18:01] <mc-> you're using 2 555s
[18:01] <jcoxon> that was the plan
[18:01] <jcoxon> however my circuit isn't playing nice
[18:01] <jcoxon> the plan was to have an astable circuit
[18:02] <jcoxon> which did the focus
[18:02] <jcoxon> and then also trigger a monostable circuit which would trigger the shutter 1 second later
[18:06] <mc-> are you using a relay to control the focus + shutter?
[18:06] <jcoxon> well then i was thinking of using a relay
[18:06] <jcoxon> as i have one
[18:07] <jcoxon> basically i can get it to focus
[18:07] <jcoxon> and toggle that
[18:07] <jcoxon> but to then make it take is causing the issue
[18:07] <mc-> you'll need 2 relays then.
[18:08] <jcoxon> it seems to me that to actually trigger the shutter repeatedly its necessary to disconnect the trigger line completly
[18:08] <jcoxon> could i use a gpio to focus
[18:08] <jcoxon> and then use my relay to trigger the shutter
[18:09] <mc-> it depends how the camera works?
[18:10] <mc-> Do you connect the wire to ground to activate the focus ?
[18:10] <jcoxon> yup
[18:11] <jcoxon> and then do the same for the trigger
[18:11] <mc-> might be safer to use a FET/transistor rather than the GPIO direct.
[18:13] <mc-> or can you join the focus/trigger together and it will take the photo after it's focussed?
[18:13] <jcoxon> sadly not
[18:13] <jcoxon> tried that
[18:13] <mc-> another idea, I think the output of the 555 is open collector, so you can use the 555 as a transistor.
[18:14] <jcoxon> oh okay
[18:14] <mc-> remove the pull-up resistor on the output of the 555.
[18:16] <jcoxon> bingo
[18:16] <jcoxon> on another note
[18:16] <mc-> it works?
[18:16] <jcoxon> oh no not the camera
[18:17] <jcoxon> but i've set up zeusbot to print the gps coordinate in the form of the google maps url
[18:17] <mc-> good idea
[18:18] <jcoxon> time to test
[18:23] <mc-> I wasn't quite right about the 555, the output isn't open collector, but the discharge transistor is open collector.
[18:27] <jcoxon> so what does that mean?
[18:27] <jcoxon> i'm rubbish at electronics
[18:28] <mc-> do you have a transistor to hand?
[18:28] <mc-> or only a 555?
[18:28] <jcoxon> haven't got transistors
[18:28] <jcoxon> never used them
[18:28] <jcoxon> though do have 3 555 chips
[18:29] <mc-> do you have any diodes?
[18:29] <jcoxon> yup
[18:30] <mc-> use the same 555 cct you have, but put a diode on the output line
[18:30] <mc-> with the diode pointing towards the 555
[18:30] <jcoxon> the astable circuit
[18:30] <jcoxon> ?
[18:30] <mc-> or the monostable, so you can test manually
[18:31] <mc-> or can you set up the astable so it triggers every few seconds?
[18:32] <jcoxon> thats what its doing
[18:33] <jcoxon> every 5 secs
[18:33] <jcoxon> sorry mc- gonna have to go, supper, will be back later - thanks for all the help
[18:33] <mc-> do you see/hear something if the focus is activating correctly?
[18:33] <jcoxon> (though what does the diode do?
[18:33] <mc-> ok, talk later
[18:33] <mc-> diode stops the voltage going into the camera
[18:35] <mc-> first thing to test, if if the camera stills focuses when you have a diode connected to gnd.
[18:35] <mc-> *is if
[18:39] <jcoxon> false alarm
[18:39] <jcoxon> i'm back
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[18:44] <mc-> rocketboy, are you a 555 expert?
[18:45] <mc-> see the logs...
[18:48] <jcoxon> mc-, right if the diode faces the 555 (so the black end is towards the chip) then it doesn't work
[18:49] <jcoxon> the other way round when the output is high then the camera focuses
[18:50] <mc-> hmm, I thought the focus activated when the wire was gnded?
[18:54] <jcoxon> okay -there are 3 wires
[18:54] <jcoxon> gnd and 2 others
[18:54] <jcoxon> if you ground "red" then it focuses
[18:54] <jcoxon> if you make "yellow" high it focuses
[18:55] <mc-> Does the camera focus when you connect the diode between the wire and gnd?
[18:55] <jcoxon> pointing which way?
[18:55] <mc-> diode pointing to gnd
[18:56] <jcoxon> for a diode is the black line at the end the direction?
[18:57] <mc-> the line is at the current exit side
[18:58] <jcoxon> doesn't work
[18:58] <jcoxon> i think my diode might be dead
[18:58] <jcoxon> right i do have to go now - thanks mc- for the help again
[18:58] <mc-> ok, let's try later
[19:06] <mc-> rocketboy, how much current do you think flows through the cutdown FET ? 3A or more?
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[19:07] <LaurenceB> hi all
[19:07] <mc-> hi
[19:08] <LaurenceB> thanks for the email mc
[19:08] <LaurenceB> I'll think about that idea of directly soldering onto the pads
[19:08] <LaurenceB> and getting a sample rate gyro
[19:10] <LaurenceB> rocketboy- what do you think to me launching a payload on sunday?
[19:10] <LaurenceB> it'll have no tracking and rely on the other payloads for recovery
[19:10] <LaurenceB> just the master unit for my glider
[19:12] <mc-> I'm worried the gas is a helium-air mix, so might to have 2 balloons...
[19:13] <LaurenceB> weigh 200 grams for my payload
[19:13] <mc-> but I don't know how much lift is got typically
[19:13] <LaurenceB> 1.2 kg m^3
[19:13] <LaurenceB> approx
[19:13] <mc-> but with a mix, it might be 0.6 kg / m^3?
[19:14] <LaurenceB> T canister -> 3.6 m^3
[19:14] <rocketboy> mc - The igniter is about 1.1 ohm before if blows - then as it flares is close to 0 ohm
[19:15] <rocketboy> so currebt is all down to FET on resistance and capacitor internal resistance
[19:15] <LaurenceB> I did some calculations based on the weight of a party balloon and helium air mix cant have much air in for it to work
[19:15] <mc-> ok, so 5V / 1.1 ohm = 5A.
[19:15] <LaurenceB> I got less than 24% air
[19:15] <mc-> I heard it was 50%
[19:16] <LaurenceB> okay, but that would mean small party balloons wouldnt fly
[19:17] <LaurenceB> we haven't had problems before, but neither have we been calculating exactly how much lift we've got
[19:17] <mc-> good point
[19:17] <rocketboy> yes upto the point it flairs then it might be 5V / (0.1 + 0.1 ohm) = 25A
[19:17] <rocketboy> assuming an RDSon of 0,1 ohm and a cap internal resistance of 0.1 ohm
[19:17] <mc-> once it flairs, it doesn't matter. Or does it blow the FET?
[19:18] <rocketboy> yeh could blow the FET
[19:18] <mc-> oh well, they're cheap
[19:19] <mc-> just ordering some from rapid, anything anyone else needs? (within reason..)
[19:19] <LaurenceB> hmmm...
[19:19] <LaurenceB> some fets? lol
[19:20] <LaurenceB> I have quite a few but they don't seem to take more than 2 amps
[19:20] <rocketboy> yeah - a couple of crock clips - hang on I'll get the No
[19:22] <rocketboy> could you get me 2 x 17-0330 and 2 x 17-0335
[19:23] <LaurenceB> could you get me 3x 47-0552
[19:23] <LaurenceB> thanks
[19:23] <icez> get me a pony
[19:23] <icez> :]
[19:24] <mc-> I've found a FMMT617T has a pulse current of 12A - there's mistake in catalogue
[19:26] <LaurenceB> so, on this launch will all the payloads be on one line?
[19:26] <LaurenceB> with cutdown at one end
[19:27] <rocketboy> yep
[19:27] <LaurenceB> so my payload could be fixed on one end?
[19:27] <LaurenceB> ie other end
[19:27] <rocketboy> yep - assuming it not too heavy
[19:27] <LaurenceB> 200 grams
[19:27] <mc-> 47-0552 isn't valid
[19:27] <rocketboy> I should think so
[19:27] <LaurenceB> wtf
[19:28] <LaurenceB> http://www.rapidonline.com/productinfo.aspx?tier1=Electronic+Components&tier2=Discrete+Semiconductors&tier3=MOSFETS&tier4=TO-220+Logic+level+power+MOSFETs+N-Channel&moduleno=77687
[19:29] <mc-> 47-0552 isn't in stock
[19:30] <LaurenceB> grrr
[19:30] <LaurenceB> can you try the next one down?
[19:33] <mc-> all out of stock
[19:34] <mc-> got the croc clips, RB
[19:36] <LaurenceB> never mind I'll get a speed controller for my plane instead
[19:38] <LaurenceB> I found my calculations on MIR balloons I did ages ago
[19:38] <LaurenceB> me and jcoxon weretalking about this earlier
[19:39] <LaurenceB> you can get about 1/15 of the lift you would from helium with a MIR
[19:40] <LaurenceB> and they only work above 18km
[19:40] <rocketboy> mc - Many thanks
[19:40] <LaurenceB> so from this you can work out the size required
[19:40] <mc-> what's MIR?
[19:40] <LaurenceB> montgolfier infra red
[19:40] <mc-> hot air?
[19:40] <LaurenceB> works off the ir emission from the earth
[19:41] <LaurenceB> yes, hot air
[19:41] <rocketboy> the black bin liner things?
[19:41] <LaurenceB> a lot bigger to work
[19:42] <LaurenceB> I estimate 15meters long at the very least
[19:42] <LaurenceB> but its buildable
[19:42] <LaurenceB> and will fly until it drifts towards the poles or encounters a tropical thunderstorm
[19:43] <mc-> so the big + is it doesn't leak helium out?
[19:43] <LaurenceB> its only been tried a handful of times but a french group circumnavigated the glode twice with one
[19:43] <LaurenceB> theres no helium, only air
[19:44] <mc-> sorry, that's what I meant.
[19:44] <LaurenceB> its filled with a bit of helium to get it up to 18km
[19:44] <mc-> so, an ultra-light payload using solar cells, could float for ages.
[19:45] <LaurenceB> atmophere is below -50 and balloon reaches -30 to -20
[19:45] <LaurenceB> so it flies due to hot air
[19:45] <LaurenceB> would need a sat phone
[19:46] <LaurenceB> mc, get, record is 4 weeks
[19:46] <LaurenceB> -yes
[19:47] <mc-> ham radio module would be OK? I'm thinking if I've got the electronics bits to build one.
[19:47] <LaurenceB> payload wouldnt need to be ultra light as it would be insignificant compared to the envelope
[19:48] <mc-> would need to be launched from the US, for the ham module.
[19:48] <LaurenceB> maybe aprs radio, but its going to go a long way
[19:49] <LaurenceB> could start be trying a solar balloon
[19:49] <mc-> morse code would be even simpler
[19:50] <LaurenceB> solar balloon would be similar to what we've already launched, just need a sunny day
[19:51] <mc-> is a black bin liner light enough? with a tiny payload?
[19:51] <LaurenceB> a wheely bin liner will only just fly, I've tried it
[19:51] <LaurenceB> need several
[19:52] <LaurenceB> wheely bin liner weighs 50 grams, so for light payload, wouldnt need too many
[19:53] <LaurenceB> as volume prop to r^3 surface, r^2
[19:55] <mc-> I can see the press headlines - Scientists flying in bin liners!..
[20:10] <LaurenceB> its nothing to what these people did
[20:11] <LaurenceB> ... find web link
[20:12] <LaurenceB> http://perso.orange.fr/ballonsolaire/en-index.htm
[20:16] <LaurenceB> to go off topic..
[20:16] <LaurenceB> http://news.bbc.co.uk/1/hi/england/essex/6226285.stm
[20:16] <LaurenceB> it says the cats eyes are solar powered
[20:16] <LaurenceB> but where are the panels?
[20:21] <mc-> saw the balloon link, if building from bin liners, I guess it's better to join a few together to increase the volume?
[20:21] <LaurenceB> yes, and make is spherical to maximize volume
[20:22] <mc-> need some lightweight tape
[20:23] <mc-> or is glue better?
[20:24] <LaurenceB> heat sealing is the way to go
[20:24] <rocketboy> bbl
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[20:24] <LaurenceB> I used it to make the MiHAB1 parachute
[20:24] <mc-> how did you do the heatseal?
[20:25] <mc-> I can control the temp of my soldering iron
[20:26] <LaurenceB> if you want to do it properly, get a teflon soldering bit and do it on a grease covered worksurface
[20:27] <LaurenceB> I just used a soldering iron and 2 sheets of greaseproof paper either side of the seam
[20:29] <mc-> and it worked?
[20:29] <LaurenceB> yes no problem
[20:29] <LaurenceB> just move the soldering iron along at the right speed
[20:30] <LaurenceB> you could try it woth some plastic bags
[20:30] <mc-> gone to look for some greaseproof paper, bbl
[20:31] <LaurenceB> depending on the type of seam it deosnt matter if you move too slowly as it just melts away the center of the bond
[20:36] <LaurenceB> any luck?
[20:51] <LaurenceB> okay my master unit now controls the camera stores eeprom data and gets the temperature
[20:52] <LaurenceB> ready to build the payload enclosure
[20:52] <LaurenceB> and order batteries
[20:54] <LaurenceB> MiHAB3 wont need a pc, everything it done through the lcd monitor :-)
[21:11] <LaurenceB> okay I'm off cya
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[22:23] <mc-> cya
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[22:44] <LaurenceB> my li poly battery should arrive tomorrow :-)
[22:45] <defy> lipol's are fun, but don't burn your house down! :P
[22:46] <jcoxon> hey all
[22:46] <jcoxon> time to crack this damn camera shutter trigger thingy
[22:47] <jcoxon> hehe amazing
[22:47] <jcoxon> i've signed up to the solarballoon yahoo group
[22:48] <jcoxon> and one of the pictures i took when i was in africa is there
[22:48] <LaurenceB> cool I'll have to have a look at that
[22:48] <LaurenceB> are you using 555 timers?
[22:49] <jcoxon> trying to
[22:49] <LaurenceB> and transistors?
[22:49] <LaurenceB> to switch the shutter
[22:49] <jcoxon> the picture is only of the military truck that brought the payloads back
[22:49] <jcoxon> i haven't got any transistors
[22:49] <jcoxon> will have to get some
[22:50] <LaurenceB> are you trying to send in logic levels into the camera?
[22:51] <defy> military truck, sheesh how big was the payload?
[22:51] <jcoxon> i'm use to just using gpios
[22:52] <jcoxon> ttl
[22:52] <jcoxon> actually its not ttl
[22:52] <jcoxon> it was a couple of payloads
[22:52] <jcoxon> the one is was working on was about 25kg
[22:53] <defy> sweet
[22:53] <LaurenceB> I'm just using a transitor wired up to work like a switch
[22:53] <defy> have you seen the space balloons doco jcoxon?
[22:53] <LaurenceB> on my camera
[22:54] <LaurenceB> I have a submini relay to turn it on and off
[22:54] <jcoxon> the Air Force of Niger had to go out and get it
[22:54] <LaurenceB> as the on off logic runs straight off the battery, and the rest of a switched mode power supply
[22:55] <jcoxon> but the balloon kept landing in Burkino Faso so they had a few difficulties
[22:55] <LaurenceB> if you connect the two grounds the camera wont work
[22:55] <LaurenceB> sounds exciting
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[22:55] <LaurenceB> wha did the payload do?
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[22:56] <LaurenceB> defy- space balloon?
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[22:58] <jcoxon> does everyone else keep getting disconnected from freenode?
[22:58] <LaurenceB> no
[22:58] <jcoxon> just me then
[22:59] <defy> it looks like your server keeps splitting jcoxon
[22:59] <jcoxon> oh right
[22:59] <jcoxon> brb then
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[23:01] <defy> LaurenceB http://science.discovery.com/tvlistings/episode.jsp?episode=0&cpi=118969&gid=0&channel=SCI
[23:01] <defy> although that url doesn't really give much info, but these guys have 4 ton payloads
[23:01] <defy> and keep it up for weeks
[23:01] <defy> pretty cool doco
[23:01] <jcoxon> thats impressive
[23:02] <jcoxon> i only know of 2 groups that can do that
[23:02] <jcoxon> CNES and NASA
[23:02] <defy> it might be about nasas group
[23:02] <defy> I don't remember
[23:02] <defy> I'll try to get the avi online if you guys want to grab it though
[23:03] <jcoxon> found a torrent i think
[23:03] <defy> sweet
[23:04] <jcoxon> there was a film crew out in africa
[23:04] <jcoxon> doubt it was them though
[23:05] <defy> only torrent i have is dead...if you can't get a copy let me know and ill upload it
[23:06] <LaurenceB> whats this video about then?
[23:06] <jcoxon> its about nasa
[23:06] <jcoxon> found the press release
[23:06] <LaurenceB> MIR balloons, superpressure?
[23:06] <jcoxon> http://www.nsbf.nasa.gov/Ballooning%20Documentary.pdf
[23:06] <LaurenceB> or just balloons in general
[23:07] <defy> watching them fill the balloons and launch is pretty darn impressive
[23:07] <jcoxon> oooo i've uploaded more pics of africa
[23:07] <jcoxon> they are on my flickr account
[23:08] <defy> url?
[23:09] <jcoxon> http://www.flickr.com/photos/29158271@N00/
[23:09] <jcoxon> though i'm not sure that'll work
[23:10] <jcoxon> search for jcoxon77
[23:10] <jcoxon> http://www.flickr.com/photos/29158271@N00/sets/72157594446369581/
[23:12] <defy> awesome
[23:12] <defy> was that helium?
[23:13] <jcoxon> yup
[23:13] <jcoxon> this one i actually launched
[23:13] <jcoxon> http://www.flickr.com/photos/29158271@N00/337403027/in/set-72157594446369581/
[23:13] <jcoxon> as in i held it down and let it go
[23:14] <defy> sweet
[23:17] <LaurenceB> cool
[23:19] <LaurenceB> http://www.flickr.com/photos/29158271@N00/337394080/in/set-72157594446369581/
[23:19] <LaurenceB> thats a fair bit of helium
[23:20] <jcoxon> we had 2 trailers worth
[23:22] <LaurenceB> http://www.flickr.com/photos/29158271@N00/337402175/in/set-72157594446369581/
[23:22] <LaurenceB> is this some sort of headquarters
[23:23] <jcoxon> yeah
[23:23] <jcoxon> that was the scientists base
[23:23] <jcoxon> our lab was the second along
[23:23] <jcoxon> we also tracked the sondes from there
[23:23] <LaurenceB> what were you launching then?
[23:23] <jcoxon> CNES had their own buildings
[23:24] <jcoxon> balloons?
[23:24] <jcoxon> from totex 1200gm to thousands of cubic metres
[23:24] <LaurenceB> yes but what did the payloads do?
[23:25] <jcoxon> lots of things
[23:26] <jcoxon> the one from cambridge was a gas chromatograph
[23:26] <jcoxon> but we also had LIDAR
[23:26] <LaurenceB> lidar awesome
[23:26] <jcoxon> ummm
[23:26] <jcoxon> some others i can't remember
[23:27] <jcoxon> a cool lightning detector
[23:27] <LaurenceB> http://www.flickr.com/photos/29158271@N00/337403611/in/set-72157594446369581/
[23:27] <jcoxon> one that measured electric field strength
[23:27] <LaurenceB> is this the lidar?
[23:27] <jcoxon> they were testing it as it was then going to go to mars
[23:29] <jcoxon> yup
[23:29] <jcoxon> thats micro-lidar
[23:30] <LaurenceB> see thats the laser in the middle
[23:31] <LaurenceB> okay I'm off then
[23:31] <LaurenceB> cya
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[00:00] --- Wed Jan 3 2007