Is there Any DIY Circuit Available for Missing Signal Release Bouy

[george]

Hello

First, not sure if this section is the place to post this, if Not can admin. move to the proper section.

I was wondering if anyone has a Small Size DIY circuit that would be a missing signal detector so if transmitter signal is lost for say 20sec. it would release a fishing line float to rescue a sub?

I would like to try to build one for my sub safety.

Plans, pictures, ALL would be helpful.

Thanks

George

[redboat219]

Been discussed here already

http://forum.sub-driver.com/showthread.php?588-Deadman-Timer-for-Emergency-Buoy-release

[RCSubGuy]

Along the principles of KISS, why not use a simple electromagnet running off of the main drive battery?

The magnet holds the buoy in place during normal operation. Should disaster strike, the sub will eventually run out of juice, releasing the buoy and allowing retrieval. Optionally, one could utilize a standalone battery to power the magnet that might drain faster than the main drive battery... say after a few hours of continued use. I like the idea of using the main drive battery, however, so as to eliminate the need for an additional waterproof container and charging of a separate battery...

Just a thought.