Super long standby VOX/transponder help needed.

[lovelian]

Hello, this is my first post and I was hoping someone could help me with where to find a very long standby Voice Activated Switch circuit.

This project is a tracking responder for high altitude balloon recovery, A gps transmitter gives the approximate location, then a whistle activates a timed beeper when we are close (100m). The balloons maybe airborne for weeks so a long standby of about 1 month is needed.

Perhaps some kind of remote control circuit would do the job?

Any help would be greatly appreciated.

 

[Arouse1973]

I assume you want this to be able to find the balloon when it has landed? You want some kind of RF beacon. I am thinking maybe a http://en.wikipedia.org/wiki/Avalanche_transceiver
Thanks
Adam

 

[lovelian]

I assume you want this to be able to find the balloon when it has landed? You want some kind of RF beacon. I am thinking maybe a http://en.wikipedia.org/wiki/Avalanche_transceiver
Thanks
Adam

Hi Adam, thanks for your reply, we did look at rf beacons but they don't transmit for long enoug, operate for days as opposed to weeks. A simple vox seems to fit the bill but can't find a circuit
with a low enough quiescent current drain.

 

[Arouse1973]

All you need to do is build a little circuit that switches on the beacon device every so often. How long would you want to wait between beacon pulses?

 

[lovelian]

sorry, couldn't log back in...

Found a pretty good vox on the talking electronics website, has a QI of .25 mA so on a 750mah lipo it should last for 4 months.

 

[Arouse1973]

Hope it works out for you.
Thanks
Adam

 

[hassan]

sorry, couldn't log back in...

Found a pretty good vox on the talking electronics website, has a QI of .25 mA so on a 750mah lipo it should last for 4 months.

hey lovelian can you explain how this circuits works and from where exactly will we take its output?