highaltitude.log.20070127

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[15:16] <Golfgeo> Hi all
[15:28] <jcoxon> hey Golfgeo
[15:29] <Golfgeo> Hope there is some activity here, still got a lot to learn about this stuff :-)
[15:30] <jcoxon> hehe - there is some activity
[15:30] <jcoxon> though it comes in waves
[15:32] <jcoxon> so are you just researching or have you started working on a project?
[15:38] <Golfgeo> I'm researching the math models needed for altitude control and looking for a cheap PC clone type motherboard so I can use Linux for flight control. But the basic design is set.
[15:40] <jcoxon> well i'm a gumstix person
[15:40] <jcoxon> but there are other boards
[15:41] <jcoxon> i like this one: http://www.acmesystems.it/?id=4
[15:43] <Golfgeo> Bookmarked :-)
[15:47] <Golfgeo> As an IT guy I know of some electronics stuff, but that isn't my main field. That is an important resone the Gumstix isn't an option for me. I need to use PC comp. interfases to simplify my design and an option I like is the Phidgets interfase boards...
[15:48] <jcoxon> i find hte phidgets boards really expensive
[15:48] <jcoxon> but i understand what you mean
[15:49] <Golfgeo> But then the price of the motherboard is a problem. One with alot of comp. is the Epia Nano and the upcomming Epia Pico. But these are priced at 250 to 350 euro's, so for something that might be lost....
[15:50] <Golfgeo> *comp. == interfases
[15:51] <Golfgeo> But the Phidgets do provide a library so my programming time can be focused on the "important" stuff, so there I'm willing to spend the euro's :-)
[15:52] <Golfgeo> But that isn't my mean problem... The math for the altitude control is difficult...
[15:54] <jcoxon> hmmm Laurence has been thinking about things like that
[15:54] <jcoxon> he's been working on the valve
[15:54] <Golfgeo> I'm looking into a way to mesure the real volume of the balloon based on the number of mols in the envelope. This so I can use mesurements of the inside and outside temp. and presure to maintain the altitude
[15:55] <Golfgeo> This by using a cannister and pump to store Helium...
[15:55] <jcoxon> how long are you looking to stay up for
[15:55] <Golfgeo> Release means loss into space of Helium...
[15:55] <Golfgeo> Round the world?
[15:55] <Golfgeo> ;-)
[15:56] <jcoxon> with a latex balloon?
[15:56] <Golfgeo> UV and gass los would be a problem...
[15:56] <jcoxon> yup
[15:56] <jcoxon> might as well work on a zero pressure mylar
[15:57] <jcoxon> long duration is a difficult one to achieve
[15:57] <jcoxon> mainly due to logistics
[15:57] <jcoxon> maintaining communications
[15:57] <jcoxon> etc
[15:59] <Golfgeo> I agree an that, but "the" APRS network would let me track the balloon... But the steps are: 1) Altitude control, 2) meteo info integration (for cource), 3) solve long term hardware limits
[16:00] <jcoxon> why not use gps and a negative feedback loop to control the altitude
[16:01] <Golfgeo> The current projects are to get high and higher with recovery. I would like to create a framework that is able to stay up there...
[16:01] <Golfgeo> negative feedback loop?
[16:01] <jcoxon> so monitor the altitude
[16:01] <jcoxon> and adjust appropriately as it drops
[16:01] <jcoxon> or goes up
[16:02] <Golfgeo> The real weather conditions determine when the balloon will burst, not an a standerd...
[16:03] <jcoxon> of course
[16:03] <Golfgeo> So at night when the temp goes down the envelope shrinks, but the GPS will still read...
[16:03] <Golfgeo> :-)
[16:04] <Golfgeo> That is why I need to do (but first completly understand) the math...
[16:05] <jcoxon> :-)
[16:05] <Golfgeo> If it all works I will have a platform for scientific research and what I will do with that is still a long way away...
[16:06] <jcoxon> hehe
[16:06] <Golfgeo> Letting up a telesope or as a technology testbed would be fun
[16:06] <jcoxon> very cool
[16:07] <jcoxon> the UK doesn't lend itself to launch long duration balloons
[16:07] <Golfgeo> Why that?
[16:07] <jcoxon> well depends how long for
[16:07] <Golfgeo> Hmm
[16:07] <jcoxon> you've got sea and then europe
[16:08] <jcoxon> there is a reason why the CNES launch in the southern hemisphere
[16:08] <Golfgeo> So? If the winds at different levels can be used to get the balloon back...
[16:08] <jcoxon> that would be impressive
[16:09] <jcoxon> i wouldn't like the idea of balloons passing through other counties aerospace
[16:09] <Golfgeo> Balloons or rockets (CNES)?
[16:09] <jcoxon> balloons
[16:09] <Golfgeo> Ah
[16:09] <jcoxon> the big people are CNES and NASA
[16:09] <jcoxon> i worked with CNES over the summer
[16:09] <Golfgeo> But at 50K KM high there are no borders ;-)
[16:09] <jcoxon> CNES pioneered the MIR balloons
[16:10] <jcoxon> hehe thats true but when it comes down...
[16:10] <Golfgeo> Don't know those balloons
[16:10] <Golfgeo> True
[16:10] <jcoxon> MIR balloons are the long duration balloons that circle around the world
[16:10] <Golfgeo> You have to use safe limits so it won't...
[16:11] <jcoxon> http://perso.orange.fr/ballonsolaire/en-historique3.htm
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[16:15] <Golfgeo> That's intresting, but Esa, Nasa and JAL can't be compaired to use simple folk... They have hugh budgets and resources driven my even bigger budgeted fields of science... We guys are just looking for some fun and this on a budget :-)
[16:16] <Golfgeo> B.t.w. what did you do with CNES?
[16:16] <jcoxon> was helping launch balloons in Niger, West Africa
[16:16] <jcoxon> i went along with some atmospheric scientists from my university
[16:16] <Golfgeo> That herican project?
[16:17] <Golfgeo> *my spelling is terible today...
[16:17] <jcoxon> this was AMMA
[16:17] <jcoxon> lots of counties looking into the West Africa Monsoon
[16:17] <Golfgeo> Monsoon...
[16:18] Action: Golfgeo was googling...
[16:18] <Golfgeo> Must have been fun :-)
[16:18] <jcoxon> yeah it was really good
[16:19] <jcoxon> some pictures are on my flickr account
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[16:19] <Golfgeo> :-)
[16:19] <jcoxon> http://www.flickr.com/photos/29158271@N00/sets/72157594446369581/
[16:20] <Golfgeo> How did you get involved with it?
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[16:20] <jcoxon> going to Niger? or balloons?
[16:21] <Golfgeo> Cnes? Or both?
[16:21] <jcoxon> oh there is a department at my uni
[16:21] <Golfgeo> Ah, ic
[16:21] <jcoxon> the head of hte department is a fellow at my college
[16:22] <jcoxon> and found out about my balloon launches and invited me along
[16:22] <Golfgeo> Yea, here in Holland those things almost never happen...
[16:23] <Golfgeo> Well, I did get to ask Steve Balmar a question at a small introduction presentation for Win XP. But that was since I bought a latop at the comp. where I bought the thing...
[16:23] <Golfgeo> *laptop
[16:24] <jcoxon> hehe
[16:24] <jcoxon> we should launch a balloon to you in holland :-p
[16:24] <Golfgeo> *where the presentaion was given///
[16:24] <Golfgeo> That could be fun
[16:24] <Golfgeo> ;-)
[16:25] <jcoxon> we got one to germany 2 weeks ago
[16:25] <Golfgeo> I have to say that here the educational system is just bad in those kinds of things, I look at Berceley webcast cources from time to time and just wonder why those things arn't here
[16:26] <Golfgeo> KM?
[16:26] <jcoxon> ?
[16:27] <Golfgeo> how many km did it travel?
[16:27] <jcoxon> oh 620
[16:27] <jcoxon> well it was found there
[16:27] <jcoxon> it was only a balloon and a radio beacon
[16:27] <Golfgeo> Ah
[16:27] <jcoxon> we scrubbed the real launch as the payloads weren't working perfectly but had an inflated balloon
[16:28] <Golfgeo> The platform from Niger looks impresive
[16:28] <jcoxon> so we added a beacon and a cutdown device on a timer and let it go
[16:28] <Golfgeo> That payload failed, right?
[16:28] <jcoxon> yup
[16:28] <jcoxon> hehe
[16:28] <Golfgeo> I read about it
[16:29] <jcoxon> obviously the cutdown didn't work as it managed to reach europe
[16:29] <jcoxon> though i think it must of landed in hte sea and got washed up
[16:29] <jcoxon> the people who found it are sending it back by post
[16:29] <Golfgeo> Still fun I imagine
[16:30] <jcoxon> yeah
[16:30] <jcoxon> the plan is to launch next weekend
[16:30] <jcoxon> the models are predicting very little wind
[16:30] <Golfgeo> The origional payloads?
[16:30] <jcoxon> actually i've scrapped my payload totally
[16:30] <Golfgeo> oke
[16:30] <jcoxon> there is a flaw in its design
[16:31] <jcoxon> i've built another one though
[16:31] <Golfgeo> :-)
[16:31] <jcoxon> gone back to my old system
[16:31] <jcoxon> gonna go for altitude
[16:31] <jcoxon> so its very light with very little onboard
[16:31] <jcoxon> i think we'll also launch another payload with cameras etc from rocketboy
[16:33] <Golfgeo> I heard that HAM isn't allowed from uncontrolled balloons, do you have biderectional communication?
[16:33] <jcoxon> not right now
[16:33] <jcoxon> but it wouldn't be difficult to set up
[16:33] <jcoxon> right now we have a downlink from the balloon
[16:33] <jcoxon> the uplink could be a HAM radio link though
[16:33] <jcoxon> as the balloon would only be reciving
[16:35] <icez> I just had a funny idea, about putting colored LEDs inside the balloon and the computer would pulse different colors in a morse-like fashion, and someone would launch the balloon at night and get some binoculars :]
[16:35] <jcoxon> hehe thats really cool
[16:35] <Golfgeo> IC, but applications like APRS wouldn's be posible at standard HAM freq.
[16:35] <jcoxon> Golfgeo, not under UK rules
[16:36] <jcoxon> however it wouldn't take much to set up a network of people to pick up 433 mhz
[16:36] <jcoxon> we are getting over 250km of range with a strong signal
[16:36] <icez> Golfgeo, are you the one from yesterday that wants to make a mapping balloon?
[16:36] <jcoxon> icez, nah thats someone else - read the logs
[16:36] <icez> :|
[16:36] <Golfgeo> lol
[16:36] <jcoxon> icez, hehe we could launch with lights and wait for the calls about a UFO
[16:37] <icez> yeah.
[16:37] <Golfgeo> got to go get dinner started, bbl
[16:37] Nick change: Golfgeo -> Golfgeo|Dinner
[16:37] <icez> put a little really loud fan under it to make a wooshing noise with it :)
[16:37] <Golfgeo|Dinner> :-)
[17:08] <jcoxon> bbl
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[19:02] <phatmonkey> hey jcoxon
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[19:22] <jcoxon> hey phatmonkey
[19:23] <jcoxon> just got your email
[19:23] <jcoxon> feel free to come up
[20:27] <phatmonkey> jcoxon, do you think i should put together a payload?
[20:27] <phatmonkey> not sure how to power it
[20:28] <phatmonkey> i might try hooking up a gps and phone to the £10 arduino
[20:29] <phatmonkey> it has a serial port plus a few i/o pins which can be used for serial data
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[20:43] <Golfgeo> Hi all
[20:43] <icez> howdy
[20:44] <Golfgeo> jcoxon, I've looked at the Foxboard and it's close, yet the multitude of expansion boards promised arn't availible like with the Gumstix...
[20:45] <icez> :[
[20:45] <Golfgeo> But, some thing close is beter than nothing...
[20:51] <Golfgeo> The USB port could be an option to use a USB-stick for a linux root partition and the integrated flash memory as the boot partition, but I would reather have a compact flash drive connected via a IDE connector...
[20:52] <jcoxon> phatmonkey, we do have quite a few payloads flying
[20:52] <jcoxon> thats why i'm not flying
[20:52] <phatmonkey> yeah
[20:53] <jcoxon> Golfgeo, i guess there isn't a perfect solution
[20:53] <Golfgeo> :-)
[20:53] <Golfgeo> Haven't found it yet, but this is pretty close :-)
[20:53] <jcoxon> phatmonkey, its up to you - if you have time to make something - go for it
[20:53] <phatmonkey> i'll give a shot
[20:54] <jcoxon> in regards to comms we don't really need more,
[20:54] <jcoxon> rocketboy and henry both have phones
[20:54] <phatmonkey> i'll try and make the cheapest/simplest possible phone and gps combo
[20:54] <jcoxon> and all three have radios
[20:54] <phatmonkey> ah nice
[20:54] <jcoxon> could put together a camera module
[20:54] <jcoxon> i'm meant to be doing one but i'm a bit delayed
[20:55] <phatmonkey> how about a video cam?
[20:55] <jcoxon> tis an idea - henry is keen to get some video
[20:55] <phatmonkey> maybe just a cheap old tape camera
[20:55] <jcoxon> but again i'm worried we are overloading
[20:56] <jcoxon> to much complication
[20:56] <phatmonkey> ya
[20:57] <jcoxon> i'm going to make a radar reflector and then run the show :-)
[20:59] <phatmonkey> need any parachutes
[20:59] <phatmonkey> i have a nice 60" one
[20:59] <jcoxon> no harm in bringing one
[21:00] <jcoxon> i've got a 36" and rocketboy has loads
[21:00] <phatmonkey> i've got bags of crap i can bring!
[21:01] <jcoxon> cool
[21:05] <jcoxon> if the weather remains like the forcast - it should be a perfect day
[21:05] <jcoxon> no need for too much chasing
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[21:09] <jcoxon> evening rocketboy
[21:10] <phatmonkey> righty, i wonder if i can find the protocols for nokia phones
[21:11] <jcoxon> check the gnokii documentation
[21:12] <phatmonkey> yeah
[21:37] <phatmonkey> no point bothering, won't be a simple task
[21:38] <rocketboy> humm phatmonky - what do want to know about NOKIA protocols - I have learned a lot about them in the last few weeks
[21:38] <rocketboy> hi BTW
[21:38] <phatmonkey> hey
[21:39] <rocketboy> there are two main protocos - FBUS and MBUS
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[21:39] <phatmonkey> just thinking about hooking up a phone to a little arduino board, but it's not worth doing (don't really have the time at the moment above all!)
[21:40] <rocketboy> FBUS is slower/older/more difficult to interface - MBUS is newer/easier IMO
[21:40] <phatmonkey> the language it's designed for is crippled anyway
[21:40] <laurenceb> Hi all
[21:40] <phatmonkey> hi
[21:40] <jcoxon> rocketboy, did you get the email i sent out?
[21:40] <laurenceb> use AT commands!
[21:41] <rocketboy> sorry jcoxon - no - I'll look
[21:41] <laurenceb> jcoxon-does the GPS still seem broken?
[21:41] <jcoxon> just wondering - i used the ukhas mailing list
[21:41] <jcoxon> laurenceb, yeah i reckon its dead
[21:41] <jcoxon> rocketboy, wasn't sure if you were on it
[21:41] <laurenceb> I might get one on ebay then
[21:42] <laurenceb> Or use a rate gyro, went to oxford model plane shop today
[21:43] <laurenceb> the guy there whos making a helicopter for the FSB is trying to get an IMU from BAE systems
[21:43] <jcoxon> hehe
[21:43] <jcoxon> that guy sounds crazy
[21:43] <laurenceb> it mental, they've given him £4K
[21:43] <laurenceb> they cant export it to russian due to the regulations
[21:44] <laurenceb> He hadn't got any cheap rate gyros tho
[21:45] <jcoxon> rocketboy, i'm going to have to dash - will speak soon
[21:45] <jcoxon> bye all
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[21:46] <laurenceb> To go off topic, does anyone know how to use LATEX?
[21:46] <rocketboy> humm rather a dodgy Q iMO
[21:46] <laurenceb> I'm trying to learn
[21:46] <laurenceb> we're supposed to be able to use it at Uni
[21:46] <rocketboy> what form - moulds
[21:47] <rocketboy> for
[21:47] <laurenceb> OKay wrong sort of latex lol
[21:47] <laurenceb> http://tug.org/PSTricks/main.cgi/
[21:47] <rocketboy> ha ha
[21:47] <rocketboy> you mean the scripting tool;
[21:47] <rocketboy> tool
[21:48] <laurenceb> yes lol
[21:48] <rocketboy> no - not really - its yonks old
[21:48] <laurenceb> I'm trying to get it to do postscript it's really annoying
[21:50] <laurenceb> anyway, I think an analogurate gyroe filter would be very useful with a rate gyro
[21:50] <laurenceb> -analogue filter
[21:51] <rocketboy> yeah - digital filtering is a bit of an ART
[21:51] <laurenceb> they are very temperature sensitive, but the temperature changes are slow
[21:51] <rocketboy> the guys making barometric altimeters for rockets have had real problems getting it right
[21:52] <laurenceb> the centerpoint drift could be filtered out and only the sensitivity would need to be adjusted by the micro
[21:53] <laurenceb> but if I can get a 4hz gps I'll be happy without a gyro
[21:54] <laurenceb> are we on track for a launch next weekend?
[21:54] <rocketboy> yeah - you have said - not sure why 4Hz is needed though
[21:54] <rocketboy> yeah next weekend it is
[21:54] <laurenceb> okay
[21:54] <laurenceb> well if its 1hz rudder update its a bit too slow
[21:55] <laurenceb> especially as theres some latency
[21:56] <rocketboy> it that from a simulation?
[21:56] <laurenceb> eh?
[21:56] <laurenceb> I've built the plane
[21:56] <laurenceb> but not really flown it, just taken it on my bike
[21:57] <rocketboy> Ans you have flown it?
[21:57] <rocketboy> and
[21:57] <laurenceb> no it was too windy/wet
[21:57] <laurenceb> and now I'm at Uni
[21:58] <laurenceb> I doubt it will be very good, 1hz + 250ms latency is too slow
[22:00] <laurenceb> but the accuracy is decent once your going fast
[22:00] <rocketboy> I guess - but I assume that is just a "feeling" rather than a practical test?
[22:00] <laurenceb> yes
[22:01] <laurenceb> who knows, but I can make it much better for sure
[22:04] <laurenceb> does anyone know of a source of rate gyros?
[22:05] <rocketboy> ebay
[22:05] <rocketboy> I got one for christmas
[22:06] <laurenceb> yes but they have built in servo driver stuff
[22:06] <laurenceb> guess I could desolder one
[22:06] <rocketboy> yep - they appear to be a pulse extender/shortener
[22:06] <laurenceb> there are only about 3 makes of sensor IC
[22:07] <rocketboy> its quite small - anout 25x25x25mm
[22:07] <laurenceb> is the sensor IC surface mount
[22:07] <rocketboy> ah - mc sent me one its about 10x10x20
[22:07] <laurenceb> ie is it desolderable?
[22:07] <rocketboy> its a little module
[22:08] <rocketboy> wire ended
[22:08] <laurenceb> or is it BGA or similar?
[22:08] <rocketboy> no
[22:08] <laurenceb> are you talking about the whole module tho or the actual sensor inside?
[22:09] <laurenceb> as the whole modules include servo driving ect, not what I want
[22:10] <rocketboy> its a murata_env-05g I think
[22:10] <laurenceb> oh cool thats the sensor
[22:10] <rocketboy> I think its the sensor
[22:10] <laurenceb> where did mc get it from?
[22:11] <laurenceb> 4pins?
[22:11] <rocketboy> don't know - its quite £££
[22:11] <rocketboy> yep
[22:11] <laurenceb> yes sensor 4 sure
[22:11] <laurenceb> yes you can buy them of www.gyroscope.com for £45
[22:12] <laurenceb> but you can get them from america 4 less than that
[22:12] <rocketboy> it seems to be 3 wire - +5 0V and sensor output
[22:12] <laurenceb> and on ebay £15 for a servo heading lock unit
[22:12] <laurenceb> the trade price is <£10
[22:13] <rocketboy> I would guess there is somthing similar inside the RC unit
[22:13] <laurenceb> yes thats why I want one
[22:13] <rocketboy> yeah £15 is about what I paid
[22:13] <rocketboy> for the one off ebay
[22:13] <laurenceb> only Analogue devices, NEC and Murata make them
[22:14] <rocketboy> I could open mine up for a gander later
[22:14] <laurenceb> so the RC modules must use one of those
[22:14] <laurenceb> good plan
[22:14] <laurenceb> let me know, and I might get one to cannibalise
[22:15] <rocketboy> sure
[22:15] <rocketboy> that was my plan - I just havn't found the time
[22:16] <laurenceb> ok I'd better b off, work 2 do
[22:16] <laurenceb> cya
[22:16] <rocketboy> cya
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[00:00] --- Sun Jan 28 2007