> You should really have isolation from the mains. The transformer scheme > is fine. I don't like the high value resistor approach.
I know what you mean. I too used to think isolation and safety meant using a transformer, like a low voltage AC wall-wart. Then out of curiosity I opened some of them to see what was inside. Sloppy design. Poor soldering. Child labor. Solder drips. No waterproofing. Fingerprints. Vinyl tape. Compared to that, a DIY, carefully constructed, direct connection of two AC lines to PIC input pins via a pair of 1 Meg flameproof resistors has merits. Perhaps what we need is transparent wall-warts, like hospital-grade power cords. Alternatively, has anyone considered grabbing 50/60 Hz from the air? Just about any dangling unshielded wire will act as a pickup. Maybe not as robust a signal, but this is not so much a problem for solutions already using a hardware or software PLL. And it certainly wins the safety prize. Call it the iClock Air... /tvb _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
