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blimp.txt
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01[08:50] <13spacekitteh> www.reddit.com/r/engineering/comments/q8r9p/what_would_be_a_good_os_for_an_autonomous_blimp/ :3?
[08:50] <RocketBoy> what was that site someone put up that will calculate the radio horizon for a given location
[08:52] <nigelvh> Damn matlab "programmers"
01[08:52] <13spacekitteh> nigelvh: shh i can code in c/cpp but it's faster to use matlab
[08:53] <nigelvh> Real men write hex.
06[08:53] * spacekitteh isn't a man :P
[08:53] <nigelvh> In all seriousness though. Matlap probably isn't really the best choice for an autonomous blimp
[08:53] <nigelvh> matlab*
07[08:53] <eroomde> spacekitteh: http://www.youtube.com/watch?v=K29dn0Mzspk
[08:53] <LazyLeopard> There was a site which identified landmarks on the horizon, which gives you some idea of how far your line-of-sight reception will go : http://www.heywhatsthat.com/
[08:53] <eroomde> there's my autonomous blimp ^
01[08:54] <13spacekitteh> wow nice
01[08:54] <13spacekitteh> mine's just gonna be like, half a meter long
01[08:54] <13spacekitteh> nigelvh: why not?
[08:54] <eroomde> it was a mix of things. linux on a single board computer (PC104) and lots of atmegas dangling off usb via ftdi chips to do things
01[08:55] <13spacekitteh> indeed
[08:55] <Upu> evening
[08:55] <eroomde> yeah this was a bit bigger
[08:55] <eroomde> has a payload capacity of about 6kg
[08:55] <nigelvh> It's not terribly efficient for one.
[08:55] <eroomde> evening upu
[08:55] <nigelvh> Also, nice blimp
01[08:55] <13spacekitteh> nigelvh it doesn't have to be too efficient
[08:55] <Upu> just did a talk on HABby stuff at local Rotary, went down well
01[08:55] <13spacekitteh> just efficient enough to do its job without crashing
[08:55] <eroomde> that's an assumption
[08:56] <Upu> some old dude who used to be in Army Air Core Survellance in the 60's was super interested
01[08:56] <13spacekitteh> if i had more than 3 months to build it, i would use c/cpp
[08:56] <eroomde> if you just want basic control, there's nothing on a blimp that's complicated
02[08:56] * LazyLeopard ([email protected]) Quit (Quit: Bye)
[08:56] <eroomde> it's a tiny wee controller, a couple of pid loops
[08:56] <Upu> Hix you about ?
[08:56] <eroomde> maybe 20 lines of C
[08:56] <nigelvh> I don't see what's so complicated about writing the C
[08:56] <Upu> Hix Jcoxon did code examples for the uBlox here : http://ukhas.org.uk/guides:falcom_fsa03
02[08:56] * Jasperw ([email protected]) Quit (Ping timeout: 276 seconds)
07[08:57] <eroomde> spacekitteh: i would do it thusly:
[08:57] <eroomde> have an arduinoconnecting to your control surfaces and motor
[08:57] <nigelvh> A few evenings and I've done AX.25 in c, or rocket data gathering/telemetry systems in c.
[08:57] <eroomde> have that run pid locally to keep it pointing along some vector
[08:57] <eroomde> then if you want a level of intelligence above that, something to do with localisation and mapping say, then that's something for matlab
01[08:58] <13spacekitteh> eroomde: yeah, i have to do vision processing
[08:58] <eroomde> but the arduino would just need to be a timer than fires off every 100ms
[08:58] <eroomde> ok
[08:58] <nigelvh> There are certainly advantages to languages higher up the chain than C, but for basic control, you're adding a lot of complexity
[08:58] <eroomde> well, that blimp was vision based
[08:58] <nigelvh> Yeah, if you're doing vision processing, then matlab makes sense.
[08:58] <eroomde> it did real time 3d reconstruction of the terrain that it was flying over
[08:58] <eroomde> but it was all in C++. but then that's because it had to be real ime
[08:59] <nigelvh> For basic control of the blimp, I'd break it down a little lower.
01[08:59] <13spacekitteh> besides, i trust my matlab skills more than my c/cpp skills
01[08:59] <13spacekitteh> nigelvh: oh sure, just for the dynamics
01[08:59] <13spacekitteh> but i figure why do it in two seperate systems
01[08:59] <13spacekitteh> especially when weight is at a premium
[08:59] <nigelvh> They don't have to be two systems, but two pieces of software can run on the system.
[08:59] <eroomde> because that's the most sensible way
[09:00] <eroomde> get a basic controller working first
[09:00] <nigelvh> Also, throwing an arduino compatible board is gonna cost near zero in weight.
[09:00] <nigelvh> And reduce complexity.
[09:00] <eroomde> treat the vision as a separate problem
01[09:00] <13spacekitteh> the vision has to guide it
[09:00] <eroomde> yes
[09:00] <eroomde> but it's still a separate problem
[09:00] <eroomde> to being able to hold a steady course
[09:01] <nigelvh> The two systems can talk. But like eroomde says, separate the problems.
01[09:01] <13spacekitteh> i absolutely intend to have seperate software
[09:01] <eroomde> the vision provides the command signal to the controller but the controller itself wants to be run locally, i would say
[09:01] <nigelvh> The arduino can handle control, and you can occasionally send up updated info from the vision stuff.
01[09:01] <13spacekitteh> i just don't see the advantage of having a seperate board
[09:02] <nigelvh> Easier to get each section going individually. Easier to test the functioning. Don't have to constantly be switching contexts to perform different functions.
[09:02] <eroomde> you never do until you do a few mechatronicsy projects
01[09:03] <13spacekitteh> why would it be easier to program an arduino than to program a linux pc?
[09:03] <eroomde> that's an easy one
01[09:04] <13spacekitteh> i can see the advantage for when an OS crashes
[09:04] <eroomde> digital control loops need regular updates
[09:04] <eroomde> for a blimp, say 10 or 20Hz
[09:05] <nigelvh> I'm not saying it would necessarily be easier. (Although generally getting access to the IO isn't as easy on a PC). But when the functions are separated, you don't have to worry about what else is interfering with your software. You can now treat it like a black box, with defined inputs and outputs.
[09:05] <eroomde> and getting your control loop to fire every 100ms or 50ms is very easy with an arduino
[09:05] <Randomskk> https://randomskk.net/u/wombat_radio.png
[09:05] <Randomskk> :D
[09:05] <Upu> great success :)
[09:05] <eroomde> it's arrived?
[09:05] <Upu> ADF7012 ?
01[09:06] <13spacekitteh> nigelvh: yeah, i just think the chances of fucking up the sytems integration is much higher than the software interfering on one board
01[09:06] <13spacekitteh> after all i'm just a third year undergrad
[09:06] <eroomde> i strongly disagree
[09:06] <eroomde> have the arduino as your interface to the blimp
[09:06] <Randomskk> eroomde: no :(
[09:06] <Randomskk> this is my ADF test board and my STM32 dev board
[09:07] <Randomskk> so, same hardware
[09:07] <Randomskk> but not the actual hardware
[09:07] <Randomskk> still no contact from cambridge circuit, so
[09:07] <Randomskk> hopefully tomorrow
[09:07] <Upu> ok
[09:07] <Randomskk> but I should be able to flash the binary and have the same thing come up ;)
[09:07] <eroomde> it can control the servos, motor etc
[09:07] <eroomde> maybe have a gyro and compass or something onboard
[09:07] <eroomde> it's EASY to do that
[09:07] <eroomde> in your reddit page you're talking about RTOS versions of linux
[09:08] <eroomde> i'm not sure you quite realise what a world of pain that is
01[09:08] <13spacekitteh> eroomde: i realise i don't quite realise that :P
07[09:08] <nigelvh> spacekitteh: It really comes down to separation of roles, and simplication of larger issues into it's component problems. Trying to do realtime stuff is much easier on something like an arduino.
[09:08] <eroomde> have the arduino do your real time stuff
02[09:08] * Dan-K2VOL ([email protected]) Quit (Remote host closed the connection)
[09:08] <eroomde> and it can jsut hang off usb
[09:08] <eroomde> then you can easily write a linux program that talks to the blimp via this one usb connection
[09:08] <Hix> hi Upu
[09:08] <Upu> hey Hix
[09:08] <Hix> thx fro that
[09:09] <eroomde> knowing that the hard realtime stuff is all happening on the arduino
[09:09] <Upu> sample code on the Wiki
01[09:09] <13spacekitteh> eroomde: shit, I totally forgot about the USB connection
01[09:09] <13spacekitteh> Yeah, you're right
[09:09] <Upu> works
03[09:09] * Dan-K2VOL ([email protected]) has joined #highaltitude
01[09:09] <13spacekitteh> yuo've convinced me ^^
[09:10] <eroomde> all the linux program CV stuff needs to do is say 'the figuring is at this vector to the blimp' and send that direction to the arduino, it can take care of the actually mechanics of flaps and thrust and stuff
[09:10] <nigelvh> We're not trying to say it's not possible, or that you couldn't play with it if you were a glutton for that kind of thing. But I for one sincerely believe this would be the easier route.
[09:10] <eroomde> ok cool
[09:10] <eroomde> the general pricipal is when it's a prototype, simple interfaces and modularity
[09:10] <eroomde> oh and USE GOOS CONNECTORS
06[09:10] * spacekitteh nodnods
[09:10] <eroomde> there endeth the lesson on econnectors
[09:10] <eroomde> GOOD*
[09:11] <eroomde> connectors*
[09:11] <nigelvh> GOOS connectors are the best.
[09:11] <Randomskk> they are my favourite of all the connectors
01[09:11] <13spacekitteh> oh yeah, one of the reasons i was thinking doing the dynamics on linux is for much easier debugging
[09:11] <eroomde> we lost hundreds of man hours to dodgy connections on our blimp
[09:11] <eroomde> arduino debugging is easy
[09:11] <nigelvh> It's not hard.
[09:12] <eroomde> there's so little to an arduino you can easily figure out what's going on and test bits in isolation
[09:12] <eroomde> also, LEDs
[09:12] <eroomde> have lots of indication leds
[09:12] <Randomskk> or use an actual debugger
01[09:12] <13spacekitteh> hmm, yup
[09:12] <Randomskk> :P
[09:13] <fsphil-laptop> different colour LEDs
[09:13] <eroomde> shelling into your blimp sounds sexy but it's actually a massive pain in the arse compared to just having a 'everything is good' led
[09:13] <Randomskk> true
[09:13] <Upu> I vote LEDS
01[09:13] <13spacekitteh> i vote both ^_^
[09:13] <nigelvh> Also, I don't know what your budget is or whatnot, but I like the soekris boards. Small, x86, the new ones have USB, etc. soekris.com
[09:13] <eroomde> oh yes both indeed
01[09:13] <13spacekitteh> $700
[09:13] <nigelvh> I have one of the older ones and I like it.
03[09:13] * whoami (542abed1@gateway/web/freenode/ip.84.42.190.209) has joined #highaltitude
[09:13] <eroomde> shelling in will be invaluable
[09:13] <whoami> hi all
[09:13] <Upu> theres a gentle reassurance in those blinkenlights
[09:13] <eroomde> exactly
[09:13] <Upu> evening whoami
01[09:14] <13spacekitteh> yeah, i'm a big fan of status LEDs
[09:14] <Hix> hi whoami
07[09:14] <eroomde> spacekitteh: i'd vote something omap based but you've said as much
[09:14] <eroomde> beagleboard/bone
[09:14] <eroomde> gumstix
[09:14] <eroomde> raspberry pi (ok not omap but similar)
[09:14] <Randomskk> would you use raspberry pi for a control thing?
[09:14] <Randomskk> it seems to be really consumer oriented
[09:14] <eroomde> n
[09:15] <Randomskk> I guess it does technically have breakouts for stuff
[09:15] <eroomde> this is for the cv
[09:15] <nigelvh> Anything works good. I just like the soekris cuz it runs pretty much unmodified x86 crap.
[09:15] <Randomskk> ah yea I guess that'd do nicely then
[09:15] <eroomde> our blimp was a 2.4ghz core 2 duo
[09:15] <eroomde> with 4gb ram
[09:15] <eroomde> and a 128gb ssd
01[09:15] <13spacekitteh> heh
[09:15] <nigelvh> Really don't want that to crash
[09:15] <eroomde> but... this is more than you likely need :)
01[09:16] <13spacekitteh> yup x3
[09:16] <eroomde> nigelvh: http://www.youtube.com/watch?v=N9Ec9fuy5zc&feature=related
[09:16] <eroomde> the black electronics pod had $60k of stuff in it
[09:16] <eroomde> and it jsut started to plummet
[09:17] <eroomde> hence olaf shouting
[09:17] <eroomde> 'Neil! Run!'
[09:17] <G0DJA> Anyone downloaded the APEXIII payload info for FL-Digi yet?
02[09:17] * Laurenceb_ ([email protected]) Quit (Ping timeout: 276 seconds)
[09:17] <nigelvh> Nice catch dude
03[09:18] * RocketBoy ([email protected]) has left #highaltitude
[09:19] <eroomde> yeah neil did well
[09:19] <eroomde> and finally, a nominal landing
[09:19] <eroomde> http://www.youtube.com/watch?v=_0m0jEfR_iw&feature=related
[09:19] <eroomde> of which i was secretly quite proud
[09:19] <eroomde> i'm not a model flyer and you have to keep the darned thing pointing into the wind without using any throttle
[09:19] <fsphil-laptop> your secret is safe with us
[09:20] <eroomde> well of course at the time i was like 'pah yeah whatever. just another landing'
[09:20] <nigelvh> Obviously
[09:20] <nigelvh> Do that shit all the time.
[09:21] <eroomde> the pricey bit was a really really nice thermal camera
[09:21] <nigelvh> I imagine so.
[09:21] <eroomde> so we did 3d maps of the terrain (try recovering texture from snow...) and then overlayed temp data
[09:21] <eroomde> to study the avalnche fields
[09:22] <nigelvh> What was a typical flight time?
[09:22] <eroomde> could get about 45 mins out of a pack
[09:22] <eroomde> that emergency landing was at 40 mins
[09:22] <eroomde> it just cut out
[09:22] <nigelvh> That's pretty good.
[09:22] <eroomde> but i had been seeing what it could do
[09:22] <eroomde> trying to loop it
[09:22] <nigelvh> Considering all you've got going.
[09:22] <eroomde> telemetry was saying it was pulling about 120A at full throttle
[09:23] <eroomde> it could do 70km/h though
[09:23] <eroomde> it was a really pretty nippy little blimp
[09:23] <nigelvh> You hauling a car battery or something?
[09:23] <eroomde> lipos
[09:23] <eroomde> lots of lipos
[09:23] <eroomde> about 3kg worth
[09:23] <nigelvh> I figured. lead is heavy
[09:23] <eroomde> usually i'd keep it at 1/4 throttle
[09:23] <nigelvh> Though, the mythbusters did make a lead balloon.
[09:23] <eroomde> which was about 8A
07[09:24] <eroomde> spacekitteh: what is your mass budget?
01[09:24] <13spacekitteh> well it's going to be a small blimp so it's probably only going to be half a kg or so
03[09:25] * jimthree ([email protected]) has joined #highaltitude
[09:25] <eroomde> mmm
01[09:25] <13spacekitteh> i literally just got the assignment yesterday and we haven't fleshed out details yet
[09:25] <eroomde> that'll go very quickly
[09:25] <eroomde> look at the gumstix, i would
[09:25] <eroomde> talk like yoda, i do
[09:25] <nigelvh> It may be better to do a wireless camera, and do the processing externally if that's an option
01[09:25] <13spacekitteh> it's not
[09:26] <nigelvh> damn
01[09:26] <13spacekitteh> indeed
[09:26] <eroomde> gumstix
[09:26] <eroomde> it has a camera input
[09:26] <nigelvh> Yeah
[09:26] <Randomskk> onboard is much cooler too
[09:26] <eroomde> !google gumstix+overo+ironstorm
[09:26] <eroomde> hopeless
[09:26] <eroomde> https://www.gumstix.com/store/product_info.php?products_id=268
[09:27] <SpeedEvil> raspberry pi - if it comes out soon
[09:27] <nigelvh> Also, get one of the arduino pros with the tiny board, and no headers, and the tqfp chip. Much lighter than the full size, same power.
[09:27] <eroomde> wifi, camera connector
01[09:27] <13spacekitteh> eroomde: hmm, that's a bit expensive
[09:27] <eroomde> you're gonna have to value every single gram on this thing
01[09:27] <13spacekitteh> yeah, i know
[09:28] <eroomde> it's same ballpark as a beagleboard which you were talking about earlier
[09:28] <eroomde> and that is 5.6g...
01[09:28] <13spacekitteh> hmm inbuilt wifi
[09:28] <eroomde> which is worthy of a doubletake
[09:28] <eroomde> it's really the most perfect thing
01[09:28] <13spacekitteh> oh wow
01[09:28] <13spacekitteh> wait, what
01[09:29] <13spacekitteh> what's the 42.6g one
[09:29] <eroomde> wifi, camera connector, 700mhz of linux, 5.6G
[09:29] <eroomde> that's with the case
01[09:29] <13spacekitteh> ah
[09:29] <Randomskk> yea the mass is insane
[09:29] <Randomskk> I had plans for an ultra-minature quadcopter using one to do computer vision
[09:29] <Randomskk> it's stupidly small
[09:30] <eroomde> it really is diddy
01[09:30] <13spacekitteh> hmm the beagleboard is <100g too
[09:30] <Randomskk> yea but 5.6g
[09:30] <Randomskk> !!!
[09:30] <nigelvh> Yes, but there's a difference between 5 and 100
[09:30] <eroomde> http://docwiki.gumstix.org/images/d/dc/Gumstix-pez.jpg
01[09:30] <13spacekitteh> i've still gotta work out mass/power/processing budgets too of course
07[09:31] <eroomde> spacekitteh: seriously, if this blimp is going to be about 1m long, you might only have 50g usable payload
01[09:31] <13spacekitteh> it'll probably be half that size
[09:31] <eroomde> right
[09:31] <eroomde> so it probably won't even take off with a 100g computer
[09:31] <nigelvh> Also you're going to need to have motor drivers as well
01[09:31] <13spacekitteh> yeah
03[09:31] * daveake_ ([email protected]) has left #highaltitude
[09:32] <nigelvh> Yeah, at half a meter it isn't lifting much of anything.
01[09:32] <13spacekitteh> fans, fins, sensors, IMU board, wifi, status LEDs,
[09:32] <SpeedEvil> Oooh.
[09:32] <SpeedEvil> The Raspberry Pi Foundation will be making a big (and very positive) announcement that just might interest you at 0600h GMT on Wednesday 29 February 2012. Come to www.raspberrypi.org to find out what's going on. Eben Upton
01[09:32] <13spacekitteh> it has to lift a tennis ball as the droppable payload
01[09:32] <13spacekitteh> i'm not sure how big that means it will be
01[09:32] <13spacekitteh> i could estimate it but i'm too tired
07[09:32] <SpeedEvil> spacekitteh: that raises the issue of getting down.
[09:33] <nigelvh> Tennis ball is about 57 grams alone
07[09:33] <SpeedEvil> spacekitteh: ite means you need enough propulsion to either have a tennisballs worth of lift beforehand, or a tennisballs worth of 'dive' capability after
[09:33] <SpeedEvil> Assuming you want it back
[09:33] <eroomde> you won't be doing this with a 0.5m long blimp
01[09:33] <13spacekitteh> i don't think i will
01[09:33] <13spacekitteh> it's a simulated rescue package
02[09:33] * thanatus ([email protected]) Quit (Quit: thanatus)
[09:33] <eroomde> no tennis balls, autonomous computer vision guided anything
01[09:33] <13spacekitteh> hmm fair enough
[09:33] <SpeedEvil> Sure!
01[09:33] <13spacekitteh> what would be a rough estimate?
[09:33] <SpeedEvil> 0.5m long, 8m tall.
01[09:34] <13spacekitteh> lol
[09:34] <SpeedEvil> A raspberry pi may be a quite a bit cheaper option.
[09:34] <SpeedEvil> Than gumstix - assuming above announce is 'we're selling them today'
[09:34] <eroomde> to put it into perspective, a 0.5m sphere of helium has a lift of 65g
01[09:34] <13spacekitteh> SpeedEvil: start construction in june
01[09:35] <13spacekitteh> eroomde: ah
01[09:35] <13spacekitteh> is that radius or diameter
[09:35] <eroomde> that's total lift, not neck lift or free lift or anything
[09:35] <eroomde> diameter
01[09:35] <13spacekitteh> neck lift/free lift?
[09:36] <eroomde> as in the mass of the balloon will be taken off that lift
[09:36] <eroomde> leaving you with even less payload
01[09:36] <13spacekitteh> ah
[09:36] <eroomde> and a blimp has a much lower volume than a sphere of its length
01[09:37] <13spacekitteh> indeed
01[09:37] <13spacekitteh> but yeah, i have 3 months for the systems engineering phase
01[09:37] <13spacekitteh> (this is a system engineering subject)
[09:37] <eroomde> yep
[09:37] <eroomde> sounds like a lot of fundamental conceptual stuff
[09:37] <eroomde> before you even get near wondering about what operating system to use
01[09:37] <13spacekitteh> well, so is the next subject next semester, but that's more the integration side of it
[09:37] <eroomde> that's lost in the noise as a design consideration
01[09:38] <13spacekitteh> yeah
[09:38] <eroomde> it'll be fun though
01[09:38] <13spacekitteh> it was more along the lines of microcontroller vs full blown computer as a tradeoff
[09:38] <eroomde> in a tough love sort of way
[09:38] <eroomde> mechatronics always is
01[09:39] <13spacekitteh> i'm not mechatronics, i'm doing an avionics degree
01[09:39] <13spacekitteh> but i guess they're close enough
02[09:39] * NigeyS ([email protected]) Quit (Read error: Connection reset by peer)
[09:40] <eroomde> you just said it was systems
01[09:40] <13spacekitteh> the subject
01[09:40] <13spacekitteh> not the degree
[09:40] <eroomde> systems means you're not allowed to say 'i just do the [x]' :)
01[09:40] <13spacekitteh> =p
[09:40] <G0DJA> For this flight on Wednesday they say "It is possible to decode both without manually changing every time by opening two instances of dl-fldigi" but with one instance open I don't seem to be able to open a second...
01[09:40] <13spacekitteh> also it seems raspberry pi are making a big announcement tomorrow
07[09:40] <eroomde> spacekitteh: you might be interested in this: http://paparazzi.enac.fr/wiki/Lisa/L
[09:41] <eroomde> autopilot with a gumstix connector on the back
01[09:41] <13spacekitteh> i'm pretty sure I won't be allowed to get a pre-made autopilot
01[09:41] <13spacekitteh> since we have to have two software engineers in our group
[09:41] <eroomde> it's OS for what it's worth
[09:41] <eroomde> software is whatever you want it to be
01[09:42] <13spacekitteh> lol
01[09:42] <13spacekitteh> i should ask whehter we're allowed to buy pre-made autopilot software
01[09:42] <13spacekitteh> i'm pretty sure that's going to be a firm no
01[09:43] <13spacekitteh> since the idea is to be able to make one ourself
[09:43] <eroomde> buy?
[09:43] <eroomde> foss :)
01[09:43] <13spacekitteh> =p
[09:43] <eroomde> but fair enough
[09:43] <nigelvh> "edit"
01[09:43] <13spacekitteh> i think the most pre-made we can get in that reguard is pre-made IMUs
[09:44] <eroomde> ok
[09:44] <eroomde> plonk a sparkfun 9dof thing on an arduino
01[09:44] <13spacekitteh> yeah, i plan to
01[09:44] <13spacekitteh> although i'm pretty sure with the amount of wiring in that room, the magnetometer is going to go haywire
02[09:44] * G0DJA (586f8c70@gateway/web/freenode/ip.88.111.140.112) Quit (Ping timeout: 245 seconds)
[09:44] <eroomde> yes magnetometers are not happy indoors
[09:44] <eroomde> ours on the blimp was not happy either
[09:45] <eroomde> just because they were within a couple of motors of the electric motors
01[09:45] <13spacekitteh> hah, that too
[09:45] <eroomde> we had quite a few imu bugs
[09:45] <eroomde> the best bug i've ever fought was on that blimp actually
01[09:45] <13spacekitteh> oh?
[09:45] <eroomde> it would only boot up when it was facing south
07[09:45] <SpeedEvil> spacekitteh: what's your budget anyway?
01[09:45] <13spacekitteh> $700
01[09:45] <13spacekitteh> lol eroomde
[09:46] <nigelvh> That's not a bug. It's a "compass" feature.
[09:47] <eroomde> the explanation would give me rsi
[09:47] <eroomde> but it was pretty cool
07[09:49] <eroomde> spacekitteh: https://www.gumstix.com/store/index.php?cPath=33
[09:49] <eroomde> there are a rnage of prices infact
[09:49] <eroomde> range*
[09:50] <eroomde> tho $199 is the cheapest with wifi
[09:50] <eroomde> Randomskk: are you using xmonad?
[09:50] <Randomskk> yes
[09:50] <eroomde> ah
[09:51] <eroomde> thought i recgnised it from that screencap
[09:51] <Randomskk> :P
01[09:51] <13spacekitteh> hmm
[09:51] <Randomskk> the distinctive red border
[09:51] <eroomde> i had a happy summer with xmonad once
[09:51] <Randomskk> on the other hand, floating window
[09:51] <eroomde> then i tried to cutomise it
[09:51] <Randomskk> haha yea
[09:51] <Randomskk> hope you like haskell
[09:51] <eroomde> not at the time
[09:51] <eroomde> might aswell have been elvish
01[09:51] <13spacekitteh> the one you linked originally seems best
01[09:52] <13spacekitteh> DSP+wifi without openGL
[09:52] <eroomde> yeah
[09:52] <eroomde> i think it's fantastic
[09:52] <eroomde> for the size and power consumption
[09:53] <nigelvh> Anyway, time for me to head home. Have a good one!
07[09:54] <nigelvh> Good luck spacekitteh
[09:54] <eroomde> see yu
01[09:54] <13spacekitteh> tata
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07[09:56] <eroomde> spacekitteh: where are you based, geographically?
01[09:56] <13spacekitteh> brisbane
[09:57] <eroomde> oh ok
[09:57] <eroomde> oh the other rule of blimp
[09:57] <eroomde> is intuition
01[09:58] <13spacekitteh> well i'm severely autistic so my intuition isn't that great
[09:58] <eroomde> remember the difference between a 0.5m blimp and a 1m blimp is the latter has eight (8) times the payload capacity
[09:58] <eroomde> by which i mean - it's not always intuitive
01[09:59] <13spacekitteh> hmm
[09:59] <eroomde> because if you double each linear dimension (twice the length, twice the width, twice the height) then you are getting the cube of double when you calc the volume
[09:59] <eroomde> and lift is a function of volume
01[10:00] <13spacekitteh> indeed ^^
[10:00] <eroomde> so if a 50cm long blimp leaves you in the poo in terms of payload, a slightly bigger blimp can make a really big difference
01[10:01] <13spacekitteh> yeah :3
01[10:01] <13spacekitteh> i'm sure that that's not going to be a problem
01[10:01] <13spacekitteh> length, that is
01[10:01] <13spacekitteh> just have to position the thrusters correctly
02[10:02] * juxta_ ([email protected]) Quit (Ping timeout: 252 seconds)
01[10:02] <13spacekitteh> also maybe i'm missing something here but how do you get a blimp to land
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01[10:03] <13spacekitteh> slight negative bouyancy with slightly down-angled thrusters?
[10:03] <eroomde> negative passively
[10:03] <eroomde> get your lift from moving
06[10:03] * spacekitteh nods
01[10:03] <13spacekitteh> we have to hover though
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[10:04] <eroomde> oh
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[10:04] <eroomde> i would have thrust vectoring
06[10:04] * spacekitteh nods
[10:04] <eroomde> trimming for neutral is tough
01[10:04] <13spacekitteh> it can be done automatically though, yeah?
[10:05] <eroomde> we have nagative so it somes down in the case of power failure
01[10:05] <13spacekitteh> like, in the autopilot
[10:05] <eroomde> as demod in that vid
01[10:05] <13spacekitteh> indeed
[10:05] <eroomde> yep it can be done automatically
[10:05] <eroomde> ultrasonic altimeter or something
01[10:05] <13spacekitteh> what sort of ratio is good?
01[10:05] <13spacekitteh> indeed
[10:05] <eroomde> if you have wifi, i'd just use that
[10:05] <eroomde> oh ratio
01[10:05] <13spacekitteh> for what?
[10:05] <eroomde> sorry i read radio
[10:05] <eroomde> my bad
01[10:06] <13spacekitteh> we can't send any data to the blimp over wifi once engines start
01[10:06] <13spacekitteh> it
[10:06] <eroomde> ok
01[10:06] <13spacekitteh> 's strictly telemetry + video from then on
[10:06] <eroomde> ratio for what?
01[10:06] <13spacekitteh> lift:payload
[10:06] <eroomde> hmm
01[10:06] <13spacekitteh> for negative passive bouyancy
[10:06] <eroomde> well, obviously payload > lift
01[10:06] <13spacekitteh> yeah
[10:06] <eroomde> but by how much i dunno
01[10:06] <13spacekitteh> what's it on yours?
[10:07] <eroomde> our circumstances would be different to yours
01[10:07] <13spacekitteh> 1.01:1 maybe?
01[10:07] <13spacekitteh> true
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[10:07] <eroomde> we had ours to be enough to fall at about 2m/s
[10:07] <eroomde> but it was a 9m blimp
01[10:07] <13spacekitteh> hmm i'm not sure that's good for us
01[10:07] <13spacekitteh> yeah
01[10:07] <13spacekitteh> oh well, testing will determine that i think
[10:07] <eroomde> and it had to fight mountain winds
01[10:07] <13spacekitteh> hehe
[10:07] <eroomde> yeah
01[10:07] <13spacekitteh> yeah we have to fight a couple of fans
01[10:08] <13spacekitteh> how many thrusters did you use?
[10:08] <eroomde> 2 main motors
[10:08] <eroomde> on either side
[10:08] <eroomde> which could be vecoteed together in elevation
[10:08] <eroomde> and then a sideways fan in the tail
01[10:08] <13spacekitteh> ah
[10:08] <eroomde> for improved pointing at low speeds
01[10:08] <13spacekitteh> indeed
[10:08] <eroomde> when there's not much air flow over the rudder
01[10:09] <13spacekitteh> we won't be moving fast enough for rudder steering
[10:09] <eroomde> yeah
01[10:10] <13spacekitteh> i'm thinking two two-axis motors on the rear
01[10:10] <13spacekitteh> with another two side facing ones, one at the front, one at the rear
01[10:10] <13spacekitteh> since the room is only about 12x12x3m
01[10:10] <13spacekitteh> a tiny turning cirlce is crucial
[10:10] <eroomde> yeah
[10:11] <eroomde> that sounds sensible
[10:11] <MLow-werk> do one of those swivel outboard motor looking things
01[10:11] <13spacekitteh> yeah that's what i was referring to MLow-werk
CMUCAM3