[McHUG] Dirty Bird I > Pre-Flight Testing Suggestions (Correction)

[Pat Kilroy]

Hi Frank,

I don't expect the internal pressure to go high 
but to drop because the seal is far from perfect; 
I don't try for a hard seal. There are protruding 
wires. All I hope for inside the capsule is for 
temps not too far from room temp. 

A poor seal is okay for ascent but makes it 
worse for descent -- when the direction of the 
cold air propagation changes to go INSIDE 
the capsule. 

We'll just take our chances I suppose. Or 
design a test to look closer at the conditions. 

Did I answer your question okay? 

Thanks and 73,

Pat

-----Original Message-----
From: Frank Rodski [mailto:k3mtt at verizon.net]
Sent: Tuesday, November 10, 2009 06:59 PM
To: pat at patkilroy.com, 
''MicroController Ham User Group - Physical Computing for Ham Radio''
Subject: RE: [McHUG] Dirty Bird I > Pre-Flight Testing Suggestions (Correction)

Pat Since you would expect that the inside pressure could get quite high (depending on how much exposure to direct sunlight), do you expect it to get high enough to affect the operation in any way. I wonder about the pressure and battery seals. The other thing I had on my mind was the plastic container. The strongest, cheapest one may be a soft drink bottle. If you really want to get it hot, paint it black. I've seem them put 100's of pounds of pressure in a liter bottle before it burst under lab testing conditions. 3, Frank K3MTT -----Original Message----- From: mchug-bounces at mailman.qth.net [mailto:mchug-bounces at mailman.qth.net] On Behalf Of Pat Kilroy Sent: Friday, November 06, 2009 6:25 PM To: mchug at mailman.qth.net Subject: [McHUG] Dirty Bird I > Pre-Flight Testing Suggestions (Correction) Oops, I meant from *7.00* volts down to when it stops working. -N8PK ---------------------------------------------- Hi Rich, Might I suggest the following, as I am doing to my latest working module: 1. Bench test with a variable power supply, with a Digital Volt Meter across it, reading your PICetSat Lite voltage code from, say 4.00 volts down to when it stops working. Create a lookup table of known values. 2. Test to see how long a set of "fresh" batteries lasts on the bench. 3. Put the module in the fridge, then in the freezer, then back at room temp and write down the temp codes, remembering to power the module (if possible) with an external power supply to subtract out for now the effects of batteries getting cold. 4. Consider with me to integrate a module in a clear water bottle ("ship in a bottle") for an experiment to see how warm the insides might get in the sun above the clouds. (Maybe this works better with two thermistors?) Food for thought. I've got a PICetSat-In-A-Bottle partially done. I am doing some calibration of my own today and tomorrow since I now have two working PICetSat II LITE modules in hand. The fun never ends! Tell us about your pre-flight testing (calibration) experience. What did you learn? Thanks! Cheers, Pat N8PK ----------------------------------------------------------------------- Date: Fri, 06 Nov 2009 15:11:43 +0000 From: "Rich Mitchell" Subject: [McHUG] Dirty Bird I To: McHUG Reflector Ihave successfully modified one of the failed balloon modules from theHamfest weekend to be a "Dirty Bird I" (We don't scrub). The module isvery similar to the one that flew at the hamfest, except the photocellhas been replaced with a voltage divider so we can monitor the battery. Here is a description of a Dirty Bird I It uses one half of the Radio Shack 276-159 Dual General- Purpose IC PC Board (these are pre-perforated to snap in half) It uses the 08M PICAXE and the small TX-443 The PICAXE is set up for on-board reprogramming It uses 2 3v coin batteries It monitors outside temperature and battery voltage It fits nicely into coffee cup packaging It is light enough to fly with party balloon helium The code includes ID on every tenth frame (K3PZN) The code turns off the transmitter between frames It still has 3 bytes of program space left! Sinceit is very similar to the Hamfest Balloon module it should have abattery life of at least 2 hours at whatever altitude the Hamfest Balloon flew. 73 Rich N3III ______________________________________________________________ McHUG mailing list Home: http://mailman.qth.net/mailman/listinfo/mchug Help: http://mailman.qth.net/mmfaq.htm Post: mailto:McHUG at mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html