Hey everyone, been prowling the forums for a while now but im trying to build a little project at the moment and it has me in a little bit of a jam.

Currently what i am looking for is a simple counter circuit (the 74LS123 has almost everything i want with a retriggerable output). However the catch is that i would like the output to increment X by input trigger counts.

Eg: setup the IC is setup count to 5 seconds, i press the trigger 5 times and hoping for 25 seconds total output before it stops.

Does anyone have any ideas on how this could be achieved? The trigger signals would be in 1sec intervals...

cheers guys

 

This is why microcontrollers are popular. I can think of a variety of ways of doing this with vanilla-flavoured logic, but not with a single counter IC.

If you don't fancy programming a micro, I could sketch out a circuit.