Burglar alarm Circuit using IC 555


Burglar alarm circuit or Theft alarm circuits are available in several forms. The above circuit was one of that kind using timer IC 555 as the main component. The circuit is very easy to construct and the cost of this circuit is also very less. So we can implement this circuit by our own and install this circuit in our home so that you can improve your knowledge and it also adds protection to your home.


The working of this circuit is very easy to understand.In the above circuit IC 555 was used as a Astable multivibrator.The Astable multivibrator puts out a continuous stream of rectangular pulses having a specified frequency. Thus by using the Astable multivibrator we can produce continuous frequency which was given as input to the speaker which makes an alarm sound in case of any disturbance in its trip wire. Pin diagram of IC 555 was given below for your better understanding.


Now we can see how we can change the Astable Multivibrator to a alarm circuit.In the above circuit the 4th pin (RESET pin) was connected to the ground using the thin strand of copper wire which is used as a trip in this circuit.The function of the 4th pin that it resets the timing interval when it was connected to the ground.

When the wire was connected the Multivibrator cant produce the rectangular pulses of constant frequency.When the copper strand is cut off then the 4th pin will have no connection with the ground.Therefore IC 555 produces the output pulse and which was given as input to the speaker thus it drives the speaker to give a noise which would scare the burglar away.Thus your homemade effective burglar circuit is ready 

The following two tabs change content below.
Frank Donald

Frank Donald

Junior Network Engineer at Tata Communications
Frank Donald is an Electronics and Communication Engineer who loves building stuff in his free time. Video games, blogging and programming are the things he loves most

Ask your query

23 Comments on "Burglar alarm Circuit using IC 555"

newest oldest most voted
Notify of

Hello Donald!
Can you please share the pcb layout of this exact circuit?


Hi guys, I know its a bit late, but the 555 will drive a relay, 200 ma coil max, from pin 3, using a diode, (IN4001) across the coil, if you use a multi contact relay, that can control 2, 3 or more seperate circuits. ie one audio alarm, one flood light, etc.

If anyone needs a drawing, their on the web, or contact adinstrator, or me, through them. no problems.
Hope that helps you guys.

David Noah

At the point when introducing this burglar alarm, you must guarantee that the whole system is appropriately wired. Legitimate establishment of the system is the key for the well being of your home and crew. Test the alarm a few times to make certain its working appropriately. The alarm ought to be noisy to the point that it can snatch the consideration of your neighbors. At that point, show a sign that you have a security alarm system. This will keep the interlopers from breaking into your house.

Security alarm system installation


thanks for the help anonymous this website is great and i have told him that i love him

Frank Donald

yeah proper installation should be made for effective functioning of this circuit.Thanks for the info..

Odessa Hanton

When installing this burglar alarm, you must ensure that the entire system is properly wired. Proper installation of the system is the key for the safety of your home and family. Test the alarm several times to be sure it’s working properly. The alarm should be loud to the point that it can grab the attention of your neighbors. Then, display a sign that you have a security alarm system. This will keep the intruders from breaking into your house. ->Odessa Hanton

Frank Donald

Thank you I too like you to visit my blog frequently

Frank Donald

yeah sure yours was a valid point…..Electronics is a wonder

Frank Donald

Thank you keep visiting my blog

hebehemi Sato

This blog post is excellent probably because of how well the subject was developped. I like some of the comments too though I would prefer we all stay on the suject in order add value to the subject!
security system review