20D Remote Shutter N3 and standard 2.5mm stereo switch

[lewmonst]

I had fabricated an adapter using the Canon RA-N3 and a stereo jack to use my mouth switch with a standard 2.5mm jack for my 10D. It worked. I sold my 10D and got a 20D. Now, when I plug it in using the same adapter, the camera fires endlessly (on multi-shot) or once and freezes (on One-shot). That is the circuit is permanently closed. I thought my shafty radio shack soldering job was just shorting, so I thought I'd try using the Canon RA-N3 adapter (N3 to T3) and the Canon T3 adapter (T3 to stereo) with my stereo mouth switch. Same problem. I've tried with several mouth switches as well. Still same problem. I know I'm shorting the circuit somewhere, it's permanently closed... But I can't figure out where.

Has anyone made a good N3 to stereo (female jack) adapter?
Am I asking for trouble trying to combine the simple 2 wire remote to the 3 wire N3 plug?
Could it be a problem with my 20D? (No one else I know has a 20D I could test it on.)
Should the Canon RA-N3 adapter (N3 to T3) and the Canon T3 adapter (T3 to stereo) work????

Is there a way to get the benefit of the half-press with the third wire when I adapt it to a stereo plug? Anyone good with circuits know what resistor and capacitor to use to add a millisecond delay in triggering the half-press right before the release?

Better yet, if anyone has already made this and is selling them, where could I find one?

The reason I need to use the mouth switch is I am mounting the camera to a helmet and getting out of airplanes, my hands must be free for other things. And the switch must be durable in 150mph winds.

Thanks in advance for the help!
Lew

[Clemmie]

I'm certainly glad you explained WHY you need a 'mouth switch'. I was beginning to wonder about that. Sounds like a good way to short circuit your head if something goes wrong, though - and the battery power is more than sufficient to prove fatal, if properly misapplied.

Is there a possibility of doing a two switch setup? One to do the focusing/metering, then the other to trip the shutter.