Freakazoid

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Hi,

Ive got an electric helicopter with a wireless cam onboard, and I was wondering If I could utilise the audio channel of that cam for something more usefull then recording 10 minutes of highpitch electric motor screech. [&:]

Im thinking about a remote batterystatus readout thingy.
Ive seen these little gismos that you can put in your plane, that lets you view how full the batterypack currently is, by howmany leds are lit.
So I was wondering, is there a way to get those leds separated, by use of the obselite audio channel, and have a nice little display on my remote that shows howlong ive got left on the heli's batterypack?

I guess some kind of simple analog modem interface is required for data en/decoding.


Can anyone help me on this one?


Cheers,
Sven

mr.rc-cam

There is usually no need for a modem or special modulation. Most of the wireless video Tx's audio channel have so much bandwidth you can feed an attenuated 1200 to 9600 Baud TTL RS-232 signal into the audio input. On the Rx end you need to level shift the audio output, buffer it, then feed into your RS-232 input of a microcontroller (with a LCD readout on it). While at it, add some other telemetry items of interest. Basic Stamps would work.