It is a modified version of the two button version
Press the one button quickly for SET and a long press for NEXT. In setting mode quick presses increments the digit, a long press moves onto the next digit
On power up the time is set to 23:50:45, as that was the time when I got the first prototype to work!
The Timer has two on states:
On with BBC Beeps every Minute :
On:
and one off state:
A long pulse moves onto the next digit
A very long pulse resets and pulses out the current time.
Updated by Doug Rice, 1st Nov 2005