two tone siren circuit schematic using one ic

This circuit is designed for children's entertainment and can be installed on bicycles, battery-powered cars, motorcycles, as well as on models and various games and toys. When switch SW1 is positioned as depicted in the circuit diagram, it generates the typical dual-tone sound associated with police or fire brigade vehicles through the oscillation of gates IC1A and IC1B. When SW1 is set to the alternative position, an old siren sound is produced, characterized by an increasing frequency that gradually decreases. This effect is activated by pressing P1, which initiates oscillation in IC1C and IC1D.

The circuit employs a combination of integrated circuits (ICs) to produce sound effects that mimic emergency vehicle sirens, enhancing the play experience for children. The core components include two pairs of operational amplifiers configured as oscillators. IC1A and IC1B are responsible for generating the dual-tone sound, which is achieved by creating two square wave signals at different frequencies. The output of these oscillators is mixed to create a composite sound that resembles the sirens of police or fire brigade vehicles.

In the alternative configuration, when SW1 is switched, the circuit transitions to a different sound generation mode. Here, IC1C and IC1D are activated. These ICs are also configured as oscillators, but their design allows for a frequency modulation effect. By pressing the pushbutton P1, the oscillation begins, producing a sound that starts at a higher frequency and gradually decreases, mimicking the effect of an old-style siren.

The circuit is powered by a low-voltage battery, making it safe for use in children's toys and vehicles. The design includes a simple interface with the switch and pushbutton, allowing for easy operation. The output can be connected to a small speaker or buzzer, which amplifies the sound for better audibility. Overall, this circuit provides an engaging auditory experience while ensuring safety and ease of use for children.This circuit is intended for children fun, and can be installed on bicycles, battery powered cars and motorcycles, but also on models and various games and toys. With SW1 positioned as shown in the circuit diagram, the typical dual-tone sound of Police or Fire-brigade cars is generated, by the oscillation of IC1A and IC1B gates.

With SW1 set to the other 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.. 🔗 External reference