The device is useful for a model fire truck and a guard system. The intervals between the signals and their duration is controlled by changing values of electrolytic capacitors C1, C3, fixed resistors R2, R4 (see diagram). Sound effects you can Supplement the indicator light, replacing the resistor R3 with a bulb from a pocket lantern 2,5ВХ0,1A. Output transformer and speaker from any small-sized transistor radio.
Recommend to read
TWO-WHEELED TOW TRUCK
Motorists know that cars happen such failure when towing on a rope may not (when there is a fault in the steering control, brake system) or impossible (with some damage to the...
THE TIMER CONTROLS THE SOUND
The device, whose scheme is published in the journal "Popular electronics" (USA), produces a positive pulse when a sound (for example, firing of the gun) reaches the microphone B1 (see...
