Panic Alarm Circuit

Imagine the Panic situation in the Midnight when an intruder tries to break into the house. This Alarm will help you with its loud Police siren to abort the attempt of intrusion. With a single clap, the circuit generates the alarm for three minutes and then goes off. This is sufficient to catch the attention of neighbours.

The circuit is a sensitive Clap switch with timer action. IC1 is designed as a sensitive inverting amplifier to amplify the sound signals from the condenser mic. Variable resistor VR1 set the sensitivity of mic and resistor R1 and VR2 set the gain of the amplifier. If the sensitivity of mic and amplifier is suitably adjusted, the circuit can detect the sound from a distance of 5meters or more.

Panic Alarm Circuit Diagram

panic alarm circuit schematic

When the mic detects clap sound, the ac signals pass through C1and IC1 amplifies the signal. This triggers T1 .When T1 conducts, the trigger pin of the Monostable Timer IC2 will be grounded and the timer triggers. With the given values of R5 and C2, output of IC2 remains high for three minutes. This high output provides power to the ROM IC UM3561. It generates the Police Siren since its pin6 remains unconnected. Resistor R8 determines the frequency of oscillation of IC3.The siren signals are amplified by T2 and the alarm tone can be heard through the speaker. Zener diode ZD gives 3.1 volt regulated supply to IC3.


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  • Capacitor

    Plz is good 2 replace 741 with ca3130

  • F.john

    But,sir can i used another IC to replace UM3561 becoz there ar local electronics in our country

  • jj

    can we include gsm feature to alert the neighbours .

  • shashank mishra

    sir ,i am making a shadow alarm detector circuit..plz do tell me how can i connect piezo buzzer,um3561 and speakers.what is the use of piezo buzzer in the circuit..

  • mariam

    sir,may i ask u something about shutter guard project?in the circuit simulation,we can’t find ic um3561.can i replace that ic with ne555?any suggestion from u sir?thank you for your reply 🙂

  • sonybagus

    Can I install output speaker with power amplifier 60W ?, I need a loud sound min. 100 dB max. 150 dB. It can make a thief will shock and run. Thanks.

    • Bradley

      You could install a 60W power amplifier, i have installed a 5W power amplifier to my circuit and that works to a high enough standard to be heard from atleast 200M away when it is inside a building and switched on, so 60W could be a little too loud. try a 20-30W power amplifier that should be enough for just a panic alarm. 🙂

  • Bradley

    Hey, i related very heavily towards this circuit for my AS coursework, however i used an op amp instead of transistors due to not having the transistors available for me to use.
    I also used a 55 to generate a oscillating light to go with the circuit to make the light trigger aswell as the siren when switched on.

    It works extremely well and the only problem i had was a slow time for capacitors charging before it functioned, however i resolved that.

    Thankyou, your circuit was very usefull.


    • musse

      Hi Bradley,

      I am currently using this schematic for my AS project this year do you know what suffix value C1 and C3 have. As in uF,pF or nF.

      Thanks for your help.

  • Vincent

    Sir, may i know what the block diagram of this panic alarm?

  • Vincent

    Dear sir, is that the mic and the ic ua741 is signal, ne555 receiver and um3561 transmitter in this panic alarm circuit?

    • D.Mohankumar

      Dear Vincent
      Mic is the sound sensor. IC 741 amplifies the sound.IC 555 is a monostable timer to give power to alarm generator IC UM 3561 for short duration

    • ashok

      Dear Mohankumar,
      thanks for your impressive replies.. Keep going..

  • Vincent

    Thank for the comment sir.
    May i know what dc circuit of power supply suitable for this circuit?

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