Andrew --

    Attached is a PDF scan of the schematic. The relay is a generic 5v SPDT
DIP relay. I found that I couldn't use a reed relay because it was too
sensitive to physical movement. Now, maybe it was the relay I was using, but
the original PC used a small DIP relay.

    The anti-flyback diode is a generic 1N914. The second I/O pin is "spare"
and buffered so it's free to control something else.


Rich

SCHEMATIC