Dual Timers to Operate Dual Relays
revised 1-20-08

This circuit has five operational components, two relays, two time adjustment potentiometers and one push button or reed switch that acts as a trigger.
When the trigger switch is closed the first relay is activated for a time (1-5 seconds) that is set by the first potentiometer.  When that time has passed the first relay opens and the second relay is activated for a time (1-5 seconds) that has been set by the second potentiometer.  When that second time period has passed that relay opens.


Schematic - The two potentiometers (R3 and R4) select a time between 1 and 5 seconds.  The power supply that is shown will power the circuit from track power. It can also be powered by 3 AA batteries or any other "clean" DC power source between 3 and 5.5 volts.


Software -

symbol relay1 = 0
symbol relay2 = 1
symbol timer1 = 2
symbol timer2 = 4
symbol trigger = 3

symbol time1 = w0
symbol time2 = w1

if pin3=0 then start: 'stay at start till trigger pressed

readadc timer1, time1
high relay1
pause time1
low relay1

readadc timer2, time2
high relay2
pause time2
low relay2

goto start