One-IC two-tones Siren

Posted on Feb 7, 2014

This circuit is intended for children fun, and is suitable to be installed on bicycles, battery powered cars and motorcycles, but also in models and other games. With SW1 positioned as shown in the circuit diagram it reproduces the typical dual tone sound of Police or Fire-brigade cars, by the oscillation of IC1A and IC1B gates. With SW1 in the ot

One-IC two-tones Siren
Click here to download the full size of the above Circuit.

her position, the old siren sound increasing in frequency and then slowly decreasing is reproduced, by pushing on P1 that starts oscillation in IC1C and IC1D. The loudspeaker, driven by Q1, should be of reasonable dimensions and well encased, in order to obtain a more realistic and louder output. Tone and period of the sound oscillations can be varied changing the values of C1, C2, C5, C6 and/or associated resistors. There is no power switch: leave SW1 in the low position (old-type siren) and the circuit consumption will be negligible.

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    USB powered LED
    Stereo sound balancer
    Electronic Siren with 2 transistors
    Selectable sensitivity Preamplifier
    Ultrasonic Sensor Switch
    LED Lamp Dimmer Circuit Schematic Diagram
    Variable inductor
    NAND gate S-R flip-flop
    Integrated OCL power amplifier circuit composed by the TDA2040
    Nine-digit password composed of the controller circuit diagram CD4017