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[aprssig] USNA Party Balloon Success!

Bob Bruninga bruninga at usna.edu
Sat Apr 28 19:28:53 UTC 2012


> Will you provide any information on telecommand 
> and cut-down stuff for us technogeeks?

It is clever I think.  Pictures next week...  a 10 ohm 1/8th watt carbon film resistor makes an excellent REUSEABLE burn device for fishing line on about 6 to 8 volts.  But to this I added a little two-pin header socket in series.  One string is tied to the resistor which burns it for release, but a second string is tied to a U shaped jumper in the 2 pin socket.  When the first string is released, then all the load is on the second string and the jumper which is pulled from the socket.

This cuts the circuit to the resistor AND gives you a telemetry data point that it is released.

I was SO CONCEREND that a comand to the burn resistor (1 amp momentary draw for up to several seconds) might lock up the whole system due to a battery dip that I wouild not get the OFF command to then turn off the current to the resistor later (The resistor does not burn through, and is reuselable so you must have an OFF mechanism).  And since each burn takes a sligtly different time, I would not trust an X second burn (though it might not hurt for Byonics to incldue a PULSE option in their command options like Kantronics did.

The burn can take up to 10 seconds depending on the voltage.

Ayway, then a telemetry input hooked to the same header lets you know when it is pulled.

That cut-down, plus our use of ICE as a slow ballast release system I think are our contributions to the state of balloon art, though probably someone has done it before.

Bob, WB4APR
Bob, WB4APR



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