timer circuit

Thread Starter


Joined Dec 14, 2011
I am new to this site
I have a X10 wireless alarm system. I want to use the 12 volt siren of a radio shack alarm system I have. I need a timer 12 volt to turn the siren on for 30 seconds off for 30 seconds. The of and on time can vary.

Thanks for any help


Joined Sep 9, 2010
Take a look at the 555 timer integrated circuit, the world's most popular I hear. You need a square wave generator circuit set to a 1 minute cycle time with a 50% (variable) duty cycle. Depending on the load you need to drive, the 555 might drive it directly. If the load is too much, you'll need a MOSFET configured as a switch.


Joined Feb 19, 2009
I'd suggest getting a 120V School Alarm buzzer, those can wake the dead.

Just plug it into an X10 outlet adapter and set the address.

I used to have one, about a 4 inch cube, and xtend on my linux box running the X10 server. Had it go off every day at 6 am, you could hear it inside the neighbor's house when it was inside mine. I ended up setting it that way since I always turned off my alarm. This system would grab 5 random numbers and display them, I had to enter their sum to shut the alarm off to prove to myself I was really awake. It was a nifty system.