Posted on Dec 19, 2012 5102
Six preset controls and seven selector switches enable a vast range of different sounds to be produced and altered at will. Such sounds as steam trains chuffing, helicopters flying, bird chirping, and machine guns firing are possible, as well as the usual police sirens, phaser guns, and bomb explosions. The circuit incorporates an amplifier giving 150-mW output into a small loudspeaker. Alternatively, a separate amplifier system can be used for disco effects, car alarms, etc.
Continuous or one-shot souods are possible. For one-shot souods, a push-button switch is provided, which can also be used to tum continuous souods on and off. A single IC, SN76477, provides all of the sound generation circuits.