LED lamp timer circuit.

Thread Starter


Joined Oct 30, 2009
I have a matrix of UV LEDs that i use to expose PCBs. I want a circuit that will switch on a relay to LED power for about 3 or 4 minutes when a start button is pressed, then switch off after that time. A nice touch would be a rotary switch that would enable me to choose various times/resistances for the timer, and an LED indicating when on and/or finished. A digital readout is totally unnecessary, and time precision is not a factor as i would test and label each position of the rotary switch and label them accordingly. Just so i have a range of about 1 to 5 minutes or so, and various times, equally spaced between them. (Approximately!) I know there are various ways to do this, 555 timers, or RC designs, but i no experience with these.

Thanks in advance.