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

[Frank Rodski]

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" <geobra at att.net>
Subject: [McHUG] Dirty Bird I
To: McHUG Reflector <mchug at mailman.qth.net>

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


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