highaltitude.log.20070103

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[12:31] <LaurenceB> my li poly battery hasnt arrived, stupid post
[12:31] <LaurenceB> oh well I'll finish the payload for sunday instead
[12:32] <defy> what kind of charger are you using for your lipols?
[12:33] <LaurenceB> special li poly charger i've bought as well
[12:34] <defy> sweet, i just got a new one today
[12:34] <LaurenceB> got an 11.1v battery and will use it to drive thetwo motors on my plane in series
[12:34] <LaurenceB> 1.2Ah , 95 grams, should run for approx 20 minutes
[12:35] <LaurenceB> and give 150 grams thrust, plane only weighs 330 grams !
[12:36] <defy> cool
[12:44] <LaurenceB> I'm going to add a sunshade on my payload so the temp sensor is alternately shaded and in the sun, will be interesting to see what happens
[12:45] <LaurenceB> I've got it logging every 15 seconds
[12:46] <LaurenceB> I've also found my calculations on a MIR balloon, a 20m diameter one made from 15um plastic will work
[12:46] <LaurenceB> or a 15m one from 10um plastic
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[12:49] <LaurenceB> when filled with helium it should reach 37km
[12:50] <defy> sounds cool, are you running any tests with your gear and glider first?
[12:50] <defy> realworld tests i mean
[13:00] <LaurenceB> I'm not makeing a MIR balloon yet lol
[13:00] <LaurenceB> I'm going to test the motorised glider when I get the battery to power it
[13:01] <defy> sweet
[13:01] <LaurenceB> I'll set it to cut out the motors after 30 seconds or so initially
[13:01] <LaurenceB> also if the lipoly voltage gets too low
[13:01] <LaurenceB> anyway I'd better be off cya
[13:01] LaurenceB (n=laurence@host81-154-84-196.range81-154.btcentralplus.com) left irc:
[14:48] <jcoxon> cool
[14:48] <jcoxon> finally downloaded that documentary
[17:06] <jcoxon> haha
[17:06] <jcoxon> now this is absolutely brilliant:
[17:06] <jcoxon> http://www.geostationarybananaovertexas.com/en.html
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[19:55] <icez> !launch
[19:55] <icez> :/
[20:00] rocketboy (n=steve@217.47.75.133) joined #highaltitude.
[20:09] <jcoxon> hey rocketboy
[20:10] <jcoxon> hey icez
[20:10] <icez> hey jcoxon :)
[20:10] <jcoxon> icez, the other command is !countdown
[20:10] <icez> aah.
[20:10] <icez> cool:)
[20:11] <rocketboy> hiya
[20:11] <jcoxon> managed to get my camera to work
[20:12] <rocketboy> excellent!
[20:12] <jcoxon> actually lost track of how my circuit works - but i'm not complaining :-D
[20:12] <jcoxon> it involves a 555 and also a DPDT relay
[20:12] <rocketboy> If it works don't knock it
[20:13] <rocketboy> I have used opto-couplers rather than relays on mine - works a treat
[20:13] <jcoxon> oh i had to use what i had available
[20:13] <jcoxon> stupid gpios don't actually go down to 0v
[20:14] <jcoxon> if at the launch the trigger mechanism does stop working i'll just stick it on movie and let it go
[20:15] <jcoxon> anything that needs to be done before sunday?
[20:15] <rocketboy> what's the chance of you adding a cut-down?
[20:15] <jcoxon> could be done i guess
[20:15] <jcoxon> i have the circuit from Peg III
[20:16] <rocketboy> I'm not sure if mine will be ready
[20:16] <jcoxon> hmmmm - okay
[20:16] <jcoxon> what part wouldn't be ready?
[20:17] <rocketboy> well the phone is't working at the mo - and I won't have been able to do as much testing - I still need to run it away form the de-buf=gger
[20:17] <rocketboy> debugger
[20:17] <jcoxon> oh right
[20:18] <jcoxon> well i've got a spare gpio
[20:18] <rocketboy> I have the box mostly built
[20:18] <jcoxon> you know the cutdown circuit from the wiki
[20:18] <rocketboy> yep
[20:18] <jcoxon> the trigger has to around 3.3v?
[20:18] <jcoxon> now when its off the gpio is around 1.5v
[20:18] <jcoxon> roughly what is the threshold
[20:19] <rocketboy> I think anything above about 2.5V will work
[20:19] <jcoxon> just making sure there is a distinction
[20:19] <jcoxon> and could i charge the circuit off a 9v (i need it for my camera trigger)
[20:19] <rocketboy> have you still got the old cut-down?
[20:19] <rocketboy> (given that it did'nt work last time)
[20:20] <jcoxon> i don't have any live cutdowns
[20:20] <jcoxon> however i tested the circuit after hte flight and it blew the cutdowns
[20:20] <jcoxon> must of been dodgey software
[20:20] <rocketboy> ah - ok then it works OK
[20:20] <jcoxon> we have to assume so
[20:20] <jcoxon> mc- has a cutdown as well
[20:21] <rocketboy> yeah - his payload tuirned up today - not sure how to test it though
[20:21] <jcoxon> do you have a spare cutdown device which you could post to me? (or is it dangerous to send by post?)
[20:23] <rocketboy> I have a spare - I can get it to you one way or another
[20:23] <jcoxon> just to test it
[20:23] <jcoxon> as i reckon we'll need a cutdown
[20:23] <jcoxon> with the winds not being perfect
[20:24] <rocketboy> yeah agree
[20:25] <jcoxon> it'll have to be just a square of coords
[20:25] <jcoxon> if we move out of it cut
[20:26] <rocketboy> yeah thats fine me tinks
[20:26] <jcoxon> excellent
[20:27] <jcoxon> i'll wire it up later tonight and make sure it lights a test bulb
[20:27] <jcoxon> need to test my new gps antenna tomorrow
[20:27] <jcoxon> haven't actually got a lock yet
[20:27] <jcoxon> but haven't really tested outside
[20:27] <jcoxon> and have only just got a active antenna
[20:28] <rocketboy> me neither - I had a real problem with the USART stop working - it would parse a couple of messages ok then stop
[20:28] <jcoxon> right will bbl
[20:28] <rocketboy> ok bbl2
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[21:42] <mc-> hi rocketboy, I sent you an email
[21:43] <rocketboy> thanks - it explains all.
[21:44] <rocketboy> is ther a cut-down somewhere?
[21:45] <mc-> have you got your radio to hand? can you test the transmitter?
[21:45] <mc-> cut-down in the parcel?
[21:46] <rocketboy> yes - I thought you had a cut-down circuit on your payload
[21:46] <mc-> yes, it's the 6 caps, and a FET on the board.
[21:46] <mc-> It should flash the LED when it fires the cutdown
[21:47] <rocketboy> Ah ok - I havn't pulled it out of the box yet
[21:47] <mc-> replace the LED with an ignitor
[21:47] <rocketboy> Ok - I'll look & let you know how I get on
[21:48] <mc-> do you have a 9V rechargeable batt anywhere?
[21:48] <rocketboy> yeah - loads
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[21:48] <rocketboy> I'll use that
[21:48] <rocketboy> I'm waiting for my RX to charge
[21:49] <mc-> great. I tested it by putting the payload outside, and could hear the beeps a few mins later
[21:49] <rocketboy> OK
[21:50] <mc-> I sent jcoxon a mp3 file of the beeps, and he decoded it (I think)
[21:50] <rocketboy> OK - I'm not good with morse - but digits are usually easy enough to decode
[21:51] <mc-> it's not in morse code, it's my format. SHall I send you the format again?
[21:51] <rocketboy> bbl
[22:10] <rocketboy> mc - yes - please send the format again.
[22:11] <mc-> done
[22:14] <rocketboy> ta - cu later
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[22:19] <mc-> cya
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[22:33] <LaurenceB> http://wiki.ukhas.org.uk/projects:mihab:mihab3_glider_master_unit
[22:47] <LaurenceB> this is what i'll be flying on sunday
[22:56] <jcoxon> excellent LaurenceB
[22:57] <LaurenceB> I haven't shown all the menus, I've made routines for doing them
[22:57] <LaurenceB> it'll work with any nokia phone screen
[22:58] <jcoxon> thats very cool
[22:59] <icez> harmless experiment :]
[23:00] <jcoxon> in true tradition the H should be covered over
[23:00] <icez> what's that aluminum foil thing?
[23:00] <LaurenceB> solar heating experiment
[23:00] <icez> ok:)
[23:00] <LaurenceB> sun heats up temp sensor
[23:01] <jcoxon> annoyingly my only camera is in my payload
[23:01] <icez> :(
[23:01] <jcoxon> so can't take a picture till saturday
[23:01] <jcoxon> when i get my other camera back
[23:01] <icez> jcoxon, put your payload in a mirror;)
[23:01] <jcoxon> heh
[23:01] <icez> in front of*
[23:01] <jcoxon> e
[23:01] <jcoxon> actually one sec i've an idea (and its not hte mirror idea :-D )
[23:02] <icez> and the orange thing is?
[23:02] <icez> spray on rubber or something?
[23:02] <LaurenceB> spray paint
[23:02] <icez> ok
[23:03] <LaurenceB> I'll glue it together a bit better tomorrow
[23:03] <icez> nice LCD by the way.
[23:11] <jcoxon> http://www.flickr.com/photos/29158271@N00/344634378/
[23:13] <icez> how did you do that?
[23:13] <jcoxon> borrowed the family camera
[23:14] <icez> ok:)
[23:14] <icez> trying to order IR LEDs samples but fairchild requires "corporate" email addresses
[23:14] <icez> :[
[23:17] <Weiss> you might find companies are willing to sponsor you...
[23:17] <Weiss> especially given previous successes
[23:18] <jcoxon> :)
[23:24] <jcoxon> i like the activity before a launch
[23:24] <jcoxon> its exciting
[23:27] <LaurenceB> that looks cool
[23:29] <LaurenceB> how did you find where the gpio and uart pins were on the board?
[23:29] <jcoxon> routers that run OpenWrt are very well documented
[23:29] <jcoxon> so the serial ports were easy to find
[23:30] <LaurenceB> how much power does it use tho?
[23:30] <LaurenceB> I have a router that uses 15W
[23:30] <jcoxon> the gpios control the LED so its a matter of toggling the gpio and looking with a multimeter
[23:30] <jcoxon> ummm 0.24A
[23:31] <LaurenceB> what voltage
[23:31] <jcoxon> i'm running it at 6v
[23:31] <LaurenceB> 1.44 watts
[23:31] <jcoxon> i ran it on 4xAA Nimh rechargables for 3.5 hours
[23:31] <jcoxon> which in theory are at 4.8v
[23:32] <jcoxon> and have a ridiculous voltage drop
[23:32] <LaurenceB> cool
[23:32] <jcoxon> so lithiums should do nicely
[23:32] <jcoxon> so 4xAA for the router
[23:32] <LaurenceB> I should try this
[23:32] <jcoxon> 4xAAA for the gps
[23:32] <jcoxon> and a 9v for the shutter trigger and also the cutdown circuit
[23:32] <LaurenceB> is it just like normal linux once its working
[23:32] <jcoxon> yeah
[23:33] <jcoxon> not that much flash memory
[23:33] <jcoxon> but i'm pretty good these days at working in small spaces
[23:34] <LaurenceB> so openwort is just a version of linux?
[23:34] <jcoxon> yeah
[23:34] <jcoxon> basically linksys uses linux on its routers and cause of the licence they have to release the code
[23:34] <jcoxon> and so people have taken the code and made it better
[23:34] <jcoxon> do more things etc
[23:35] <jcoxon> give a lot more control
[23:35] <LaurenceB> so if you use linux in a commercial product you have to release the code?
[23:36] <jcoxon> well the source has to be avaliable
[23:36] <icez> Weiss, previous success? hahahaha.
[23:36] <jcoxon> however this is just the kernel
[23:37] <jcoxon> i think you can keep your additions as a binary
[23:37] <jcoxon> actually maybe not - as that story wouldn't make sense
[23:38] <LaurenceB> how do you program it then? use scripts
[23:38] <jcoxon> shell and perl scripts
[23:38] <jcoxon> perl handles the gps
[23:38] <LaurenceB> and log in via the ethernet?
[23:39] <jcoxon> wireless
[23:39] <jcoxon> but that'll switch off on launch
[23:39] <LaurenceB> it's wifi router?
[23:39] <jcoxon> yup
[23:40] <LaurenceB> how much was it on ebay?
[23:40] <jcoxon> 15 pounds
[23:40] <LaurenceB> cool
[23:41] <jcoxon> this payload is v. cheap
[23:41] <jcoxon> gps cost me 10 pounds
[23:41] <jcoxon> phone i already had
[23:42] <LaurenceB> how much doeas it weigh tho?
[23:42] <jcoxon> 650g in total
[23:42] <LaurenceB> not bad
[23:42] <jcoxon> though i haven't added the cutdown circuit yet
[23:42] <LaurenceB> MiHAB2 was about 600 grams
[23:43] <LaurenceB> does cutdown come of gpio?
[23:43] <jcoxon> it'll be triggered by one
[23:43] <jcoxon> i have a circuit like on the wiki
[23:50] <LaurenceB> some good photos
[23:50] <LaurenceB> I'm just thinking about this launch on sunday, It's going to be heavy with all the payloads we're putting on it
[23:51] <jcoxon> how heavy is your payload?
[23:51] <jcoxon> rocketboy is working on the assumption of a 2kg payload
[23:51] <LaurenceB> what size balloonare we using?
[23:51] <jcoxon> 1000g
[23:51] <LaurenceB> my payload was ment to be 200 grams
[23:52] <LaurenceB> but its gone over a bit, I'll weigh it when the paints dried properly
[23:52] <jcoxon> okay
[23:52] <jcoxon> with the winds they way they are it'll be a short flight methinks
[23:52] <LaurenceB> I weighed it earlier - 230grams
[23:52] <jcoxon> i reckon we should slightly overfill
[23:52] <jcoxon> go for ascent speed
[23:53] <LaurenceB> okay if we've got a 1000gram balloon we cold get quite high
[23:54] <jcoxon> yeah
[23:54] <LaurenceB> I've been redoing my calculations on MIR balloons, and it looks like a 10m diameter balloon would work
[23:54] <jcoxon> woohoo fixed my trigger circuit
[23:54] <LaurenceB> if it was made of 10um plastic
[23:55] <LaurenceB> and had a 1 or 2 kg payload
[23:55] <LaurenceB> it would work if launched from the uk in summer
[23:56] <LaurenceB> the tricky bit is the circular bit of mylar across the center of the balloon
[23:57] <LaurenceB> as this would need to aborb IR on the bottom and not emit it from the top
[23:59] <LaurenceB> Mylar is polyester film with an aluminium coating on one side, from some experiments I was doing at uni, I think polyester will absorb IR, so if the aluminised side was uppermost, it might work by itself..
[00:00] --- Thu Jan 4 2007