highaltitude.log.20080201

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[12:07] <Laurenceb> hi ed
[12:08] <Laurenceb> I've just been over to the cnc shop, the ioniser is taking shape :D
[12:08] <Laurenceb> I'll get some photos when its finished on monday
[12:13] <Laurenceb> they were polishing it with brasso :D
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[14:25] <Laurenceb> hi
[14:25] <Laurenceb> prpplague: you any good with c ?
[14:26] Action: prpplague has been known to program in c
[14:26] <Laurenceb> while(timer1overflows<(1*F_CPU/256)); //1 second normally
[14:26] <Laurenceb> I want to change that to 1.5 sec
[14:26] <Laurenceb> while(timer1overflows<(1.5*F_CPU/256)); //1 second normally
[14:26] <Laurenceb> will that work , F_CPU is an unsigned long
[14:27] <Laurenceb> or will gcc treat 1.5 as an integer?
[14:28] <prpplague> Laurenceb: yea that should work, 1.5 should be cast to make it work
[14:28] <Laurenceb> k
[14:28] <Laurenceb> btw, I've put some scope shots of the radio up on the wiki page
[14:28] <prpplague> Laurenceb: personally, i'd do it this way:
[14:29] <prpplague> while(timer1overflows<((1*F_CPU/256)*1.5)); //1 second base value and set for 1.5 seconds
[14:29] <Laurenceb> k, good plan
[14:30] <prpplague> oops miss a )
[14:30] <prpplague> while(timer1overflows<((1*F_CPU/256)*1.5))); //1 second base value and set for 1.5 seconds
[14:30] <Laurenceb> why the 1*F_CPU ?
[14:30] <Laurenceb> why not just F_CPU/256
[14:31] <prpplague> Laurenceb: code wise, it could be removed, however, reability wise, it's easier, imho, to understand that you are using the base f_cpu
[14:32] <Laurenceb> I see
[14:32] <prpplague> Laurenceb: you see alot of code written in that style for the linux kernel
[14:33] <Laurenceb> right
[14:33] <Laurenceb> http://wiki.ukhas.org.uk/_media/projects:dscn0962.jpg
[14:33] <prpplague> Laurenceb: i would also expect that the (1*F_CPU/256) to be set as a #define, i.e. #define CORE_TIMER (1*F_CPU/256)
[14:34] <prpplague> while(timer1overflows<(CORE_TIMER*1.5))); //1 second base value and set for 1.5 seconds
[14:34] <Laurenceb> oh thats a good idea
[14:34] <Laurenceb> :D
[14:35] <Laurenceb> but this is all a bit of a bodge, ideally I'd hibernate the avr and have it wake on interrupt
[14:35] <Laurenceb> I might write some really good power saving code over the weekend
[14:36] <Laurenceb> you can turn off the radio module, and disable the unused hardware in the avr
[14:36] <Laurenceb> then just wakeup to send a lacation every 30 seconds or so, should be possible to have an average current draw of 1ma @ 3v
[14:37] <prpplague> nice
[14:38] <Laurenceb> i was reading the avr-libc faq
[14:38] <prpplague> i meant to ask, when using RTTY to xmit info like location, do you repeat the info several times to makes the ground station received it?
[14:38] <Laurenceb> theres lots of cool techniques to reduce current
[14:38] <Laurenceb> no
[14:39] <Laurenceb> I'm planning on adding a CRC
[14:39] <Laurenceb> with the python code
[14:39] <Laurenceb> but it will send a packet of 100 bytes or so every 3s approx
[14:41] <Laurenceb> If you use the picopower avrs, you can shut them down and have them wake on a timer, drawing less than a microamp
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[14:42] <Laurenceb> I keep meaning to more over to arm7, but you can do so much with avrs
[14:43] <Laurenceb> I've yet to find that I cant do something for lack of clock speed
[14:44] <Laurenceb> I guess an avr is about as powerful as everything nasa used for apollo :P
[14:45] <edmoore_> more so
[14:45] <Laurenceb> who needs a PC
[14:45] <edmoore_> We're using ARM7 basically for USB stuff
[14:45] <Laurenceb> yes
[14:45] <edmoore_> and the IMU will take advantage of the processing speed, infact
[14:45] <Laurenceb> I dont like usb, too high level
[14:46] <Laurenceb> true
[14:46] <Laurenceb> an IMU needs a lot of power
[14:46] <edmoore_> but the flight computer is all AVRable
[14:46] <edmoore_> well it can sort of use as much power as you give it
[14:46] <Laurenceb> but still, I've seen AVR IMUs
[14:46] <edmoore_> it's a 3 variable equation. Refresh rate, algortihm complexity, and processor speed
[14:47] <edmoore_> each affects the other
[14:47] <Laurenceb> yes
[14:47] <Laurenceb> the thing I found was about 25Hz or something
[14:47] <edmoore_> so I guess an arm7 is a nice thing to throw at it that should keep us going for a while
[14:47] <edmoore_> yeah, we're looking for about 10 times that
[14:47] <Laurenceb> right time to reflash the radio... how long are the tuneup pulses?
[14:48] <Laurenceb> I've just changed it to 3s total
[14:48] <Laurenceb> from 2
[14:48] <Laurenceb> and repeating every 14s if theres no data... sound sane ?
[14:52] <prpplague> Laurenceb: even with the crc, how does the payload know that the ground station received the info
[14:52] <prpplague> Laurenceb: ?
[14:52] <Laurenceb> it doesnt
[14:52] <prpplague> Laurenceb: ahh thats what i thought
[14:53] <prpplague> Laurenceb: if you were using RTTY for both uplink and downlink, you'd transmit using the same freq? i.e. payload sends data/ground receives .... ground send data/payload receives ?
[14:54] <Laurenceb> no
[14:54] <edmoore_> probably a seperate one
[14:54] <prpplague> Laurenceb: or would you use seperate freqs for that? one for each
[14:54] <Laurenceb> you'd use different frequencies
[14:54] <Laurenceb> yes
[14:54] <edmoore_> laurenceb, we're transmitting heartbeat constantly
[14:54] <edmoore_> well actually, a selection of 80's hits as midi files is what we're working on
[14:55] <prpplague> hehe
[14:55] <edmoore_> it's so much easier to have something constantly there when you're trying to find it on the yagi
[14:55] Nick change: edmoore_ -> edmoore
[14:55] <prpplague> edmoore_: RYRYRYRYR ?
[14:57] <edmoore> could do
[14:58] <edmoore> The next one starts NOVA VI HH:MM:SS [telem]
[14:58] <edmoore> the NOVA VI and UTC time being a sanity check
[14:58] <prpplague> ahh
[14:59] <edmoore> I guess we could put that in so amateurs could listen if they found it
[15:00] <edmoore> but then they might actually get the telem and figure out who we are, then write us angry emails for sending 80's hits over 433mhz
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[15:02] <prpplague> hehe
[15:04] Action: Laurenceb is sending gps over his radio :P
[15:05] <Laurenceb> unfortunately the modules arent here yet, so I'm just viewing it on the scope
[15:05] <Laurenceb> the radiometrix ntx2 should be here on monday, so we test it fully then
[15:06] <Laurenceb> it was only £13.60
[15:06] <prpplague> Laurenceb: nice
[15:06] Action: prpplague plans to order some stuff for testing
[15:06] <Laurenceb> 1.5*CORE_TIMER cause timer1overflows to overflow
[15:06] <Laurenceb> that freaked me out for a bit
[15:07] <prpplague> Laurenceb: oh?
[15:07] <Laurenceb> I'd have to use a larger datatype than unsigned int
[15:07] <Laurenceb> hang on a minute,,,
[15:07] <Laurenceb> that doesnt make sense
[15:08] <prpplague> Laurenceb: this is on an avr correct?
[15:08] <Laurenceb> hmmm must be something to do with how 1.5*CORE_TIMER was evaluated
[15:08] <Laurenceb> yes mega168
[15:09] <Laurenceb> I'll leave it at 1s for the time being, and if its a pain to tune then I'll try and change it
[15:09] <Laurenceb> I've had similar problems before, when defines are evaluated, it can throw a fit
[15:09] <prpplague> Laurenceb: odd
[15:10] Action: prpplague tests with his device
[15:10] <Laurenceb> gcc evaluated defines using an "appropriate datatype" i think
[15:10] <Laurenceb> something like that, so if its wrong things can overflow
[15:11] <prpplague> i'm using avr-gcc, seems to work here
[15:11] <Laurenceb> have you actually flashed an avr?
[15:11] Action: prpplague runs another test
[15:11] <prpplague> Laurenceb: atmega48 and atmega128
[15:11] <Laurenceb> ok, what clock speed?
[15:13] <prpplague> 4 and 6 mhz
[15:13] <prpplague> low speed stuff
[15:13] <Laurenceb> ok
[15:13] <prpplague> we are trying to get away from using avr's in most of the product lines
[15:13] <Laurenceb> I'm using 12MHz
[15:13] <Laurenceb> how come?
[15:14] <prpplague> Laurenceb: just doesn't make good business sense now days
[15:14] <Laurenceb> ok
[15:15] <prpplague> Laurenceb: in the past when asic's for doing specific jobs like keyboard matrix decoding or power management controls were either not available or were too expensive
[15:15] <prpplague> Laurenceb: pics and avr's with custom code made sense
[15:15] <prpplague> Laurenceb: now days, we can get off-the-shelf silicon
[15:15] <Laurenceb> wow cool :P
[15:15] <prpplague> Laurenceb: for about the same price as the avr's
[15:15] <edmoore> How am I going to get a degree done when 'Flight of the Conchords' exists as a program I can watch. I may aswell give up now
[15:15] <edmoore> http://www.youtube.com/watch?v=pPyuZ6ZTqmo&feature=related
[15:16] Action: prpplague isn't familiar with that
[15:16] <Laurenceb> me neither
[15:16] <edmoore> it's new. and quite brilliant
[15:17] Action: prpplague doesn't watch much tv
[15:17] <prpplague> i have been watching that new show "the big bang theory"
[15:17] <prpplague> i suspect it will be cancelled soon as it is too geeky
[15:18] <Laurenceb> the physics dept here just got £100000 to make an "educational film"
[15:18] <prpplague> wow
[15:18] <Laurenceb> crazy stuff give it to me :(
[15:19] <Laurenceb> I need a working scope
[15:19] <Laurenceb> where I dont have to take photos of the screen
[15:19] <Laurenceb> still its better than working at home in my shed
[15:20] <prpplague> Laurenceb: hmm, 999990 quid on cool gadgets, 10 quid on foam balls to use in film as molecules
[15:20] <Laurenceb> theres even a heating system
[15:20] Action: prpplague heads to weekly engineering meeting
[15:20] <prpplague> bbiab
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[16:33] <jatkins> hi all
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[17:44] <Laurenceb> hi folks
[17:44] <Laurenceb> our pump has arrived :D
[17:45] <Laurenceb> we should have all the hardware for the aerosol hab finished by monday afternoon
[17:45] <Laurenceb> apart from the enclosure
[17:45] <Laurenceb> Hi Simon-MPFH
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[18:10] <Hiena> Good evening!
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[18:30] <Laurenceb> hello
[18:38] Action: Laurenceb is writing some power efficient radio code
[18:39] <Laurenceb> basically power down everything thats unneeded, and sleep the cpu when its not doing anything, waking with interrupts
[18:41] <Hiena> Most telemetry system do that. You could increase the the battery lifetime, if you does same with the ADC reading and using burst transmission.
[18:46] <Hiena> But be carefull, some sensors need time to set after the power up from the sleep. I made that mistake some years ago. So i rather use a big buffer capacitor on the sensors, wake-up all together, sending back the CPU to sleep, and waking up with the watchdog 0.2-0.5 sec later, reading the whole sensors as fast as possible, and sending back them to sleep.
[18:47] <Hiena> Also, I prefers analogue sensors, because they not requires any communication to read.
[18:48] <Laurenceb> theres no sensors on my radio board
[18:49] <Laurenceb> :D
[18:49] <Laurenceb> I'm thinking you could stick a solar cell on it and make some sort of tracking device
[18:50] <Hiena> Laurenceb, yet... Did i mentioned, how easy to hook up some sensors to the tuners I2C lines? ;)
[18:55] <Laurenceb> grrr
[18:55] <Laurenceb> will the wdt continue when the cpu is sleeping?
[18:58] <Hiena> Depends on the CPU. As i remember, the PIC's is running and the AVR based is too. But i programmed WDT at last, about two years ago...
[19:00] <Laurenceb> oh its ok
[19:00] <Laurenceb> I can set watchdog to 8seconds
[19:01] <natrium42> hrm
[19:01] <natrium42> not sure my gps receiver will arrive with the snow storm & all
[19:04] <Hiena> Yup, the PIC's pW technology is kind of handy. For example, if you use it with some SRAM LCD display and save tons on the battery side.
[19:04] <Hiena> natrium42, where is your location? And how bas the show storm?
[19:04] <Hiena> Khm..bad...
[19:05] <Laurenceb> time for some food bbl
[19:05] <natrium42> http://maps.google.ca/maps?f=q&hl=en&geocode=&q=Kitchener,+ON,+Canada&ie=UTF8&z=11&iwloc=addr&om=0
[19:06] <natrium42> it's supposed to be 20-30cm of snow
[19:06] <natrium42> lectures got cancelled...
[19:07] <natrium42> bbl, gotta drive to send some mail
[19:07] <natrium42> :S
[19:08] <Hiena> Have fun!
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[20:48] <edmoore> evening everyone
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[20:49] <Laurenceb> hi all
[20:54] <Hiena> Sleepmode on.
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[21:15] <Laurenceb> linux is so much nicer for programming
[21:15] <Laurenceb> than xp :P
[21:17] <natrium42> duh
[21:17] <Laurenceb> natrium42: can you offer an y advice on this? http://www.nongnu.org/avr-libc/user-manual/group__avr__watchdog.html
[21:18] <Laurenceb> I cant get that initialisation code to compile
[21:18] <natrium42> hrm, i never used WDT
[21:18] <natrium42> only to switch it off on boot :)
[21:18] <Laurenceb> should it be __attribute__ ?
[21:18] <Laurenceb> ie __ not _
[21:19] <natrium42> usually it's __
[21:19] <Laurenceb> and the answer is yes
[21:19] <Laurenceb> it compiles now... very odd
[21:20] <Laurenceb> cool my radio is now very very nice, theres a watchdog and power saving
[21:20] <natrium42> yay for phantom bugs
[21:21] <Laurenceb> my aim for this weekend is to perfect the radio code and write a first draft of the python script
[21:22] <Laurenceb> I also need to write some decent comments and a readme, as this is going to be used on other hab projects here
[21:26] <Laurenceb> natrium42: http://pastebin.com/mffa9d2b
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[21:36] <Laurenceb> yay it still fits on a mega48
[21:36] <Laurenceb> with 15 bytes free lol
[21:42] <Laurenceb> but thats not an issue as I'm using the mega168 anway
[21:54] <Laurenceb> natrium42: so your back at university now?
[21:58] <natrium42> yep
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[21:59] <jatkins> hi everyone
[22:02] <Laurenceb> hey there
[22:02] <Laurenceb> natrium42: finishing your old course?
[22:02] <natrium42> my bachelors
[22:02] <natrium42> of CS
[22:02] <Laurenceb> nice
[22:03] <Laurenceb> have you thought about getting further qualifications?
[22:04] <natrium42> sure, but i don't know yet
[22:04] <natrium42> might just work more on my company after i finish
[22:04] <Laurenceb> I see
[22:05] <Laurenceb> I'm not sure what I want to do next year
[22:05] Action: natrium42 never makes long term plans :(
[22:05] <Laurenceb> I met some people from bae systems the other day, looks very nice, but I'm not sure if its my kind of place
[22:05] <natrium42> ah
[22:05] <natrium42> i applied to google btw
[22:05] <Laurenceb> its like an extension of the army
[22:06] <natrium42> waiting for the phone interview
[22:06] <Laurenceb> ok
[22:06] <Laurenceb> I dont like google very much
[22:06] <Laurenceb> sorry
[22:06] <Laurenceb> :P
[22:06] <natrium42> hehe
[22:06] <natrium42> i am mainly interested in their cellphone division
[22:06] <Laurenceb> ok
[22:06] <natrium42> not into search :P
[22:06] <Laurenceb> me neither
[22:06] <Laurenceb> I just think they are so hypocritical
[22:06] <Laurenceb> with their work in china
[22:07] <natrium42> ah
[22:07] <natrium42> well, it's mostly the gouvernment's fault
[22:07] <natrium42> google has to operate under local laws or get out the country...
[22:08] <natrium42> so maybe if they can put the foot into the door for now
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[22:08] <natrium42> they will be able to extend freedoms later on
[22:08] <natrium42> anyway, it's a hard issue :)
[22:08] <Laurenceb> they just remnd me of some of the student organisations around here
[22:08] <natrium42> gotta pick up my brother, bbl
[22:08] <Laurenceb> cya
[22:25] <Laurenceb> bbl
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[00:00] --- Sat Feb 2 2008