well i know the MAX232 uses a charge pump to produce elevated voltage. the problem with that is, i thought of making a charge pump last week and it turned out that any capacitor that's big enough to hold like one second worth of high voltage charge is about 10x too big for my device. that was a real let down.You could also use one of the chips intended for driving RS232 line levels from an mcu like the MAX232.
There is an example circuit here intended for driving 40kHz piezo transducers.
EDIT: ok i gotta go to the store. back in 1/2, THANX everyone for your expertise, it really helps.
Last edited: