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I managed to make it out to the lab for a bit today.
I added a relay to the kids electric ride on Jeep replacing on/off with forward/reverse. They never turn the damn thing off anyway! I bypassed the on/off switch and cabled it separately. Originally the on/off and "go" buttons were in series. The on/off now energizes a relay for reverse, when unpowered the NC position on the relay is forward. I used a simple DPST reverser configuration where the power enters the NC terminals then crosses over to the NO terminals creating a polarity switch. The motor is fed from the centre common terminals.
Also on the list - a white noise generator. After messing around a few nights ago and not getting anywhere, I tried another circuit. This time using BC548s and a 12V supply. One BC548 is reverse biased and the E-B junctions zener effect is used as a noise source. The base of the reverse biased BC548 is then fed into the base of another BC548 to be amplified and then coupled with a 10uF cap to another BC548 for further amplification. At one point while I was messing around it was receiving radio - probably from the audio amp section. The whole thing is on a bread board, so its not that protected from interferance.