In this thread I discover I need a relay. So I head on over to Radio Shack thinking they’d be a dime a dozen. The only relays they had are 12V. I need one that will trip with 1V to 3V. I’m not sure if there are other electronics stores around that may have a low voltage relay (I’ll look).
But I’ve got a drawer full of diodes, resistors, transistors from back when I used to know what to do with them. There’s gotta be a way I can string some of these things together to close a switch in the presence of a current as described, i.e. the current going to the little watch speaker.
I did find a schematic for a solid state relay as well as this one (pdf), but one tripped by 5V, and both have overkill design for a way-higher load than I need.
I’ll keep looking, of course, but if you can either give me a quick how-to or point me to a schematic I’d be much obliged.