On Thu, Jun 23, 2011 at 9:09 AM, Barry Gershenfeld wro= te: > BTW, I, too, have made pulse generators out of junked LCD+PIC boards we h= ave > kicking around here. =A0After watching them rent omigosh-priced function > generators to do things like make tones and simulate buttons being pushed= , I > went and made my own. =A0That's how I confirmed what the lower frequency = limit > was--I could try it. =A0Never could come up with an easy power supply for > them, though. =A0Until now. =A0I have abandoned my purist > USB-is-not-a-power-supply views and joined the ranks of the lowlife lapto= p > fan and light-em-up-plug-in-sushi makers, and now I hang surplus USB cord= s > on everything I want to power. > USB can be a power supply and it can be a power supply complies to USB-IF standards if you can spend a bit of money. Check the USB Charging Specification here. http://www.usb.org/developers/devclass_docs --=20 Xiaofan --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .