Matt Barrow wrote:

This might help
http://www.matronics.com/archive/arc....digest.vol-hx

Nothing there that I saw...

Requires no batteries or buzzer or lights:
http://www.matronics.com/searching/g...WBUTTO NS=YES

This is quoted in the link above. No reference to where the schematic is
located though:
http://www.matronics.com/searching/g...WBUTTO NS=YES