The proposed circuit is an oscillator circuit designed to generate a loud pistol like sound over a loudspeaker.
A pistol sound generator circuit presented here can be used as button operated starting sound during racing events or marathons, or simply to deter wild animals and thieves in remote areas. The concept could be also effectively applied in festivals such as Diwali for creating loud artificial bursting cracker sound (noise pollution is bad for health).
The circuit utilizes a discarded 60 watt loudspeaker for producing the banging loud pistol sound.
The main components that form the power oscillator circuit are T1 and T2 along with the mains transformer TR1.
S1 is used to initiate or power up the above circuit stage momentarily with a single push of the button.
The zener diodes provide the required protection to the transistors against inductive voltage spikes.
Since the oscillator circuit is a self oscillating circuit, its frequency is determined by the core material of the transformer, and also the magnitude of current drawn from the secondary of the transformer.
How the Circuit Operates
On pressing S1, the circuit begins oscillating at relatively high frequency which finally settles down to around 50 Hz as soon as C1 and C2 charges up.
The resistor R5 limits the current to acceptable limits, while the linked diodes D3, D4 form a voltage doubler configuration.
The voltage doubler stage is introduced to create many hundreds of voltage across the attached relay contacts.
The LED D6 lights up when C1, C2 are fully charged, and indicates S1 can be now released, and the second switch S2 is ready for the activation.
When the "fire" button S2 is pressed, the relay energizes, switching ON its contacts, which discharges an instantaneous high magnitudes of current and voltage over the loudspeaker coil, generating the required banging pistol sound. It must ensured that the speaker coil is adequately rated for handling this huge amount instantaneous blast of power.
The current consumption immediately after pressing S2 could be around 3 amps, which gradually comes down to around 0.5 amps as the C1 and C2 discharges to their nominal ranges.
The loudness or the "bang" volume of this pistol sound generator could be proportionately increased by raising the supply voltage to about 12V.
The complete circuit diagram of the proposed pistol sound simulator circuit could witnessed below: