Author Options:

How to make a timer switch? Answered

I want to make a timer circuit for my aquarium light so it  stays on for  12 hours and off for 12 hours. Can anyone provide a circuit diagram?



Best Answer 4 years ago

Use a wall wart for the 12VDC


Thanks for the best answer.

In adjusting the unit, when set for 24 hrs the yellow LED

should blink every 5min 37sec.


4 years ago

I have been using something similar for some time. It is a DIY. The final mess is in the enclosed photo. It does the following:

  1. Switches on my aquarium lights at evening and switches it off at bed time.
  2. Switches the aquarium pump on and off at stipulated intervals through out the day.

I used the following:

  1. Arduino microcontroller.
  2. RTC module.
  3. Relay modules.
  4. LCD module (optional)
  5. Power supply modules, wires etc.

I have used a "cannon to kill a mosquito" (lazy me). If you are interested, I can prepare an instructable for you.


One of the timers from one of those projects can however be set to turn on or off at a certain time, so it would work the same way, so as the store bought ones.

Best buy a plug in timer. they are cheap and accurate.