[00:00] <jcoxon> http://flickr.com/photos/jcoxon77/3290922905/
[00:01] <natrium42> coolness
[00:02] <natrium42> jcoxon, maybe it's worth scripting their site?
[00:02] <jcoxon> on the case already
[00:02] <natrium42> oh, excellent :)
[00:03] <jcoxon> okay, now there is alittle trick to this
[00:03] <jcoxon> the plot is at 10km alt
[00:03] <natrium42> mike also suggested monitoring the weather
[00:03] <jcoxon> so we'd need to get the balloon at 10km at 12Z on the 24th to make it
[00:03] <jcoxon> rather then launching at 12Z
[00:07] <natrium42> predicting is serious business.
[00:07] <jcoxon> oh yeah
[00:07] <jcoxon> i plan to get good at it
[00:07] <natrium42> that's the hardest part of the mission, imo
[00:10] <jcoxon> so whats the plan about permission?
[00:11] <jcoxon> we've got envelopes - book a window for 1 months time?
[00:14] <natrium42> yep, i should email them
[00:14] <jcoxon> okay perhaps we should decide on a launch site
[00:15] <jcoxon> if we could avoid US airspace that might be a good idea as its one more thing to sort out
[00:16] <natrium42> also, how long is it going to be above canada and at what altitude?
[00:17] <jcoxon> Maine is an annoying state - sticks right into canda
[00:17] <jcoxon> will rise to float altitude of between 10 and 11km
[00:17] <jcoxon> i reckon up to 6hrs before being out to sea
[00:18] <natrium42> ok
[00:18] <natrium42> is it easier to launch from USA?
[00:18] <natrium42> did SNOX need to get a launch permission in advance or did they just have to notify ATC just before launch?
[00:19] <jcoxon> i think the got permission in advance
[00:19] <natrium42> perhaps we should ask mike
[00:19] <jcoxon> i'm not sure there is any advantage of USA
[00:20] <jcoxon> the further north we are the better
[00:20] <jcoxon> while colder the winds seem to be faster
[00:20] <jcoxon> oh we are going to need a heater
[00:21] <jcoxon> also what sort of launch conditions are you going to need?
[00:21] <natrium42> heater?
[00:21] <jcoxon> yeah onboard
[00:21] <jcoxon> its going to be very very cole
[00:21] <natrium42> what for?
[00:21] <jcoxon> cold*
[00:21] <jcoxon> stop the radio drifting too much
[00:22] <jcoxon> 3 days of -50
[00:22] <natrium42> it's possible to use temperature compensated oscillators
[00:22] <jcoxon> true
[00:22] <Laurenceb> hello
[00:22] <natrium42> hi Laurenceb
[00:22] <Laurenceb> you could use the 1pps to stop the drift maybe
[00:23] <jcoxon> natrium42, okay i'm having a look at google earth
[00:23] <Laurenceb> if the drift is < about 10KHz
[00:23] <Laurenceb> then just use a frequency counter
[00:23] <jcoxon> how about just north of tronto such as Barrie
[00:23] <jcoxon> gets us a bit further north - is still relatively close to you
[00:24] <jcoxon> hopefully the traj will pull us round the top of maine, if not we'll just inform ATC
[00:24] <natrium42> sure, that's fine
[00:24] <shellevil> 2.5ppm txco's are quite widely available
[00:24] <natrium42> barrie is close
[00:24] <shellevil> specced down to -30
[00:25] <shellevil> and cheap
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[00:39] <SpeedEvil> Laurenceb:
[00:40] <SpeedEvil> Laurenceb: 9g camera board + 1.5g battery + 10g case
[00:41] <SpeedEvil> Laurenceb: PCB is about the width of a credit card + 1cm - 70mm? by 14mm or so
[00:42] <SpeedEvil> camera is mounted flat on board, but is on a bit of ribbon cable that looks ~1cm long, so can be pivioted around the long axis of the PCB
[00:42] <SpeedEvil> And the switch is fucking fragile, and was broken.
[00:44] <jcoxon> urgh hurry up hysplit downloading - i want to go to bed!
[00:44] <Laurenceb> neat
[00:44] <Laurenceb> so the camera could be repositioned for a good view
[00:45] <Laurenceb> cylindrical battery?
[00:46] <SpeedEvil> no
[00:46] <SpeedEvil> li-ion
[00:46] <SpeedEvil> err
[00:46] <SpeedEvil> li-po
[00:46] <SpeedEvil> about 40*5*14
[00:46] <natrium42> bbl food
[00:46] <natrium42> g'nite jcoxon
[00:47] <Laurenceb> ah interesting
[00:47] <Laurenceb> any idea on mah?
[00:47] <SpeedEvil> I would guess 150Wh/Kg is sane
[00:47] <SpeedEvil> so .2Wh, or 60-100mAh?
[00:48] <Laurenceb> yeah guess
[00:49] <SpeedEvil> stk1261 based - but that seems to have exactly no english hits
[00:50] <Laurenceb> stk1261?
[00:51] <SpeedEvil> the name of the ASIC
[00:51] <Laurenceb> ah
[00:52] Action: SpeedEvil ponders soldering the battery and switch back onto this thing.
[00:55] <SpeedEvil> If you care, you can prolly get the weight down to about 6g, by pulling off the huge USB connector
[00:56] <SpeedEvil> snipping off the shell'd prolly get you 1.5g and still work even
[00:58] <Laurenceb> if you removed the camera, how thick is the pcb?
[00:59] <SpeedEvil> eyeballing, without the USB, 6mm
[01:00] <SpeedEvil> the camera adds about 6-8mm to that.
[01:00] <Laurenceb> ok
[01:00] <Laurenceb> cool, perfect for embedding in the door on the rogallo
[01:00] <SpeedEvil> ###o#####UUU
[01:00] <SpeedEvil> o = camera #=pcb, U = USB
[01:01] <Laurenceb> cool
[01:01] <SpeedEvil> the camera has a little flex-cable going to it that will let it piviot 'down'and under the PCB, pointing backwards
[01:01] <SpeedEvil> not much more than that
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[01:25] <SpeedEvil> http://www.mauve.plus.com/20931008160914.AVI
[01:25] <SpeedEvil> in about 35s
[01:25] <natrium42> SpeedEvil, you got your DX order?
[01:26] <SpeedEvil> yes
[01:26] <SpeedEvil> 5/6ths of it
[01:27] <SpeedEvil> 1/6th of it is stillen-route.
[01:27] <natrium42> nice
[01:27] <SpeedEvil> For reference, the illumination on that avi at the bright spot is about...
[01:27] <natrium42> with any luck i should get mine tomorrow
[01:27] Action: SpeedEvil thinks.
[01:27] <SpeedEvil> Probably around 3000 lux
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[01:32] Action: SpeedEvil tries to see how long it runs.
[01:34] <SpeedEvil> ok - started
[01:35] <SpeedEvil> hmm - switched off
[01:38] <SpeedEvil> Comedy manual - an example. 6: The charge finished, the yellow light [there is no yellow light, but...] twinkle stops , turn yellow lights ( at this time the yellow lights have stopped twinkle) battery has been full of instructions at this time!
[01:42] Action: SpeedEvil haz DMM!
[01:43] <SpeedEvil> Ok - bat at 4.2V - it shouldn't be turning off due to that.
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[02:00] <natrium42> ENGRISH!
[03:02] <natrium42> Laurenceb, there?
[03:03] <Laurenceb> yes, for a bit
[03:03] <natrium42> should i hardwire the venus chip for 115200 baud?
[03:03] <natrium42> or add jumpers
[03:04] <Laurenceb> how would you do that?
[03:04] <Laurenceb> sorry I'm not familiar
[03:04] <Laurenceb> theres config pins?
[03:04] <natrium42> it has two pins to select baudrate
[03:04] <Laurenceb> ok
[03:04] <natrium42> but you can also change it via software
[03:04] <Laurenceb> yeah, want it as fast as poss
[03:04] <Laurenceb> guess it depends what you can fit in and control
[03:04] <natrium42> ok, so no need to add complexity
[03:05] <natrium42> k, going to hardwire it
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[06:59] <natrium42> made a pcb for venus gps chip and sarantel geohelix antenna --> http://www.natrium42.com/gallery2/v/balloon/transatlantic/venus-gps.jpg.html
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[14:50] <SpeedEvil> natrium42: looks good. That adequate decoupling?
[16:33] <SpeedEvil> For those of us in the UK.
[16:33] <SpeedEvil> rapidonline.com
[16:34] <SpeedEvil> are having a bit of a sale.
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[17:31] <jcoxon> afternoon all
[17:31] <shellevil> Afternoon.
[17:33] Action: jcoxon has been in dissection for the last 6 hours
[17:35] <shellevil> I hope they sewed you back together after.
[17:35] <shellevil> Todays dissection for me has been limited to a steak.
[17:35] <jcoxon> hehe
[17:38] <shellevil> My GSM 'bug' arrived today - about to dissect to see what's in it.
[17:39] <jcoxon> gsm bug?
[17:45] <shellevil> $30 or so - quadband GSM - audio only
[17:45] <shellevil> 3cm (or so) cube
[17:47] <jcoxon> interesting
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[19:18] <natrium42> SpeedEvil, there's only one VCC pin on the chip and they recommend a single 1 uF cap
[19:37] <jcoxon> hey natrium42
[19:38] <natrium42> hi jcoxon
[19:39] <jcoxon> right i've worked out the command line for hysplit so it won't take long to automate it
[19:39] <jcoxon> also i got an email about the valve, they are going to send me a quote for them
[19:41] <natrium42> k, exellent
[19:42] <natrium42> bbl coffee
[19:42] <natrium42> i was up till almost 6 am :S
[19:43] <jcoxon> wow
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[20:35] <natrium42> hi rjharrison_
[20:35] <natrium42> so how's weather outlook for the weekend?
[20:36] <shellevil> nat: K - decoupling - on reflection it's all HF stuff, and no large amount of logic - so 1uF should indeed be fine.
[20:36] <natrium42> let's hope so :)
[20:37] <natrium42> i made 4 different gps PCBs
[20:37] <natrium42> each for different antenna
[20:37] <natrium42> going to see how well they work...
[20:43] <shellevil> nat: you're on GMT-6?
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[21:09] <natrium42> GMT-5
[21:09] <natrium42> hi Laurenceb
[21:16] <Laurenceb> hello
[21:22] <SpeedEvil> Laurenceb: rapidonline.com - sale today. ~30% off random electronics stuff.
[21:22] <Laurenceb> ooh cool
[21:22] <SpeedEvil> till midnight
[21:23] <SpeedEvil> Oh - and I haven't been able to get the camera to record for over ~1 min. Usually it goes for ~15s.
[21:23] <SpeedEvil> I don't understand why.
[21:26] <jcoxon> arrrggghh stupid hysplit + GFS
[21:29] <jcoxon> can get it to work with NAM data set but not GFS
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[22:25] <jcoxon> WOOHOOOO
[22:25] <jcoxon> got it working
[22:32] <Laurenceb> cool
[22:33] <SpeedEvil> :)
[22:33] <Laurenceb> whats hysplit designed for?
[22:34] <Laurenceb> tracking pollution?
[22:34] <jcoxon> yeah
[22:34] <jcoxon> and volcanic eruption fall out
[22:34] <jcoxon> i guess also weapons such as chem fallout
[22:34] <Laurenceb> and nuclear
[22:34] <Laurenceb> and hallams reactor :P
[22:35] <SpeedEvil> I wonder if volcanic is significant enough to alter its own weather
[22:35] <jcoxon> oh yes definitely
[22:35] <Laurenceb> yeah
[22:35] <jcoxon> most effect the worlds weather
[22:36] <Laurenceb> my mphys supervisor published tons of papers on it
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[22:43] <jcoxon> hey RocketBoy
[22:49] <RocketBoy> yo
[22:49] <RocketBoy> Has anyone got an implemntation of dominoex or MFSK-16 I can take a look at?
[22:49] <jcoxon> fldigi source is a good place to look
[22:49] <jcoxon> or Laurenceb put code on the wiki
[22:51] <RocketBoy> ta - I don't want to have to re-invent the wheel unless I have to
[22:52] <jcoxon> RocketBoy, we've made quite a bit of progress
[22:53] <RocketBoy> top notch
[22:53] <jcoxon> got 3 enevlopes
[22:53] <natrium42> :)
[22:53] <Xenion> Gute Nacht alle miteinander / Good Night folks ! :-) sleep well
[22:53] <SpeedEvil> Night.
[22:54] <natrium42> gute nacht Xenion
[22:54] <jcoxon> RocketBoy, yeah got them from the person who made the SNOX flight balloons
[22:55] <SpeedEvil> jcoxon: the XP film?
[22:55] <SpeedEvil> Z
[22:56] <RocketBoy> oh right
[22:57] <jcoxon> yeah
[22:57] <jcoxon> and natrium42 has sent off some flight 'puter pcbs
[22:57] <jcoxon> and have found some valves for the ballast tanks
[22:58] <natrium42> RocketBoy, http://www.natrium42.com/gallery2/v/balloon/transatlantic/
[22:59] <natrium42> hmm, is it OK to use a n-channel mosfet to turn gps on/off?
[22:59] <natrium42> or should i use p-channel?
[23:01] <RocketBoy> well if you use a n channel you will need about 3V more than the gps rail voltage
[23:01] <RocketBoy> A p channnel would make more sense where supply voltages are limited
[23:02] <SpeedEvil> The GPS and the blackfin both use 3.3v?
[23:02] <SpeedEvil> The GPS doesn't have a nice suspend pin?
[23:02] <natrium42> SpeedEvil, it doesn't
[23:02] <natrium42> RocketBoy, not sure i follow: 3v more
[23:03] <natrium42> i have 3.3 volt rail
[23:03] <SpeedEvil> RocketBoy: if you're switching the + rail
[23:03] <SpeedEvil> nater:
[23:03] <SpeedEvil> natrium42: you need 3V over that rail to turn the N channel device on
[23:04] <SpeedEvil> natrium42: so a p-channel is easiest - connect source to 3.3V, drain to the GPS, gate to the blackfin (through a 10K resistor, with also a 10K resistor to ground is prolly a good plan)
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[23:04] <SpeedEvil> Ensure the transistor has an adequate Rds(on) at -50C
[23:04] <SpeedEvil> As it climbs quite a lot.
[23:05] <natrium42> so i cannot use n-mosfets to switch 12V loads for example?
[23:05] Action: natrium42 is puzzled
[23:05] <SpeedEvil> natrium42: you can - but you have to switch on the negative line
[23:06] <natrium42> yes, exactly
[23:06] <SpeedEvil> natrium42: or provide a gate drive that swings beyond 12+gate threshold volts
[23:06] <SpeedEvil> In the case of the GPS, switching the negative rail will pull all the data lines high
[23:06] <RocketBoy> so for a n channel the FET drain will go to your 3.3V rail, the source to the GPS and the gate will need 6.3V or so on it to turn it (and the gps on)
[23:06] <SpeedEvil> and pull current out of the data pins, which may be a bad thing
[23:06] <natrium42> right now, source is connected to gnd, gate is connected to atmel (pulled down to ground through a resistor)
[23:06] <SpeedEvil> and won't actually turn it off due to the protections.
[23:07] <natrium42> so i am switching the GND of the GPS
[23:07] <natrium42> not a good idea?
[23:08] <RocketBoy> where as for a p channel the source would go to the 3.3V rain the drain would go to the GPS power line and the FET gate wound need 0V on it to turn the FET and the GPS on
[23:08] <SpeedEvil> Is it output only?
[23:08] <SpeedEvil> the GPS
[23:09] <natrium42> it has both, but i am probably going to use the output only
[23:09] <natrium42> so it's not a good idea to switch components on/off using their GND?
[23:10] <natrium42> that would give me freedom to use any VCC voltage for them
[23:10] <SpeedEvil> You need to make sure that - from the GPSs point of view that you never - when it's unpowered - pull the inputs/outputs below the current '0' voltage
[23:10] <RocketBoy> nights guys
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[23:11] <natrium42> hm
[23:12] <SpeedEvil> It's more of an issue if switching (say) a 5V device with outputs.
[23:12] <SpeedEvil> Connected to a 3.3V device say
[23:13] <SpeedEvil> If you switch the 0 of the 5V, then the 5V devices ground is now at 5V
[23:13] <natrium42> ok, i will change some of my mosfets to p-channel
[23:13] <SpeedEvil> so any 3.3V logic line connected to this will be pulled up to 5V through the protection diodes of the device.
[23:13] <SpeedEvil> of the switched device
[23:13] <natrium42> any suggestions on a mosfet type to use to switch components on/off?
[23:14] <SpeedEvil> which will in effect mean that at best, it won't turn off all the way.
[23:14] <SpeedEvil> your favourite parametric selector...
[23:14] <natrium42> k, got it, thanks for the explanation
[23:14] <SpeedEvil> Hmm.
[23:14] <SpeedEvil> Digikey I suppose
[23:15] <natrium42> did you say that you would also add a resistor between mosfet and micro?
[23:15] <natrium42> i have a pull-down
[23:16] <SpeedEvil> hmm.
[23:17] <SpeedEvil> natrium42: yes - in some wierd conditions - spikes in voltage on the drain - you can get charge going through the gate-drain capacitance, that overvolts the micro
[23:17] <SpeedEvil> probably not really an issue in this case, but it's a good security blanket.
[23:18] <natrium42> ok
[23:18] <SpeedEvil> wow - digikeys parts selector sucks.
[23:18] <natrium42> would you mind looking over the schematics?
[23:18] <SpeedEvil> (wrt fets - no vgs(th)
[23:18] <SpeedEvil> sure
[23:18] <natrium42> let me just fix some things we talked about
[23:18] <SpeedEvil> do you know if mouser is sane for canadian orders?
[23:19] <natrium42> yeah, i used them a few times
[23:21] <Laurenceb> jcoxon: did you get a reply from sensortechnics?
[23:22] <SpeedEvil> natrium42: does http://gb.mouser.com/Search/Refine.aspx?N=4932268+4294689185+4294441333+4294598068+4294443295 pop up a list of transistors?
[23:22] <natrium42> weird, the 12V jack component pinout is wrong in default EAGLE library
[23:22] <natrium42> SpeedEvil, yes
[23:24] <SpeedEvil> http://gb.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMveMCOqFR6qCOfXv445njT%252bdfUjE67JgIw%3d looks plausible
[23:24] <jcoxon> Laurenceb, yeah, they are sending me a quote
[23:24] <SpeedEvil> not horribly expensive, decent rds(on) even at 2.5V
[23:34] <natrium42> cool, thanks
[23:36] <natrium42> so we will use the 8 n-mosfets for cutoffs only
[23:36] <natrium42> jcoxon, got 8 dedicated cutoffs :)
[23:36] <natrium42> i will add a few p-channel mosfets to switch power to external components
[23:37] <natrium42> bbl food
[23:39] <jcoxon> bbl phone
[23:40] <SpeedEvil> bbl aliens.
[23:41] <Laurenceb> abduction time
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[23:47] <jcoxon> back
[23:49] hallam (i=836fc8c8@gateway/web/ajax/mibbit.com/x-61c4368b5ee7e445) joined #highaltitude.
[23:50] <hallam> hey all
[23:50] <hallam> fergusnoble: was it enthought python that you recommended? should I just get the 30 day trial?
[00:00] --- Fri Feb 20 2009