Several circuits of musical car horn have been published in BEP but “Double tune car reverse horn” differs from them. Projects like this helps you to get more used to various electronic devices. The circuit that produces the double tune car reverse horn generates two types of sounds: one is a pleasant ‘ding-dong’ bell sound and the other one is a sweet chirping sound of a bird.
Here, the IC HT82D (IC1) is used as the sound generator whose operating voltage range is 2 to 5 volts. It has 10 I/O ports and is connected with a DPDT (Double Pole Double Throw) switch via pin 9 and pin 10. The DPDT switch has 2 pins for input and 4 pins for output. With each input pin having 2 corresponding output pins, either of the input pins are always in 1 of 2 output terminals making it a very convenient switch with versatility. Here, the DPDT switch SW1 in the circuit selects the sound. When it’s position is at the top, pin 9 of IC1 is connected to the power supply (common poles of the switch are connected to each other), then the chirping sound of a bird is generated. Whereas, when the position of the switch SW1 is at the bottom, pin 10 is grounded, and a ‘ding-dong’ sound is generated.
After moving selector switch SW1, the push-to-on switch SW2 has to be operated .When SW2 is released the circuit switches off. Any low-voltage, 8-ohm speaker can be used. By using a 9-volt or 12-volt battery eliminator, the circuit can be used as a door-bell.
Readers are advised to ask for the ‘dual melody generator IC’ from the component shops to make this circuit because some dealers may not recognize it from its number HT82D.
Check out other various different sound generator posted in bestengineeringprojects.com
- Grasshopper Sound Generator Circuit using 555 Timer IC
- Multi Sound Generator Circuit
- Wind Sound Generator Using IC 741
- Rain Sound Generator
PARTS LIST OF DOUBLE TONE CAR REVERSE HORN
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Resistor (all ¼-watt, ± 5% Carbon) |
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R1 = 180 KΩ R2 = 270 KΩ R3 = 820 Ω |
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Capacitors |
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C1 = 100 µF, 12 V (Electrolytic Capacitor) C2, C3 = 0.1 µF (ceramic disc) |
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Semiconductors |
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IC1 = HT82D (dual melody generator IC) IC2 = 7805 (5V series fix voltage regulator IC) T1 = BC548B (General Purpose NPN Transistor) T2 = SL100B (Medium Power NPN Transistor) D1 = 1N4001 (Rectifier Diode) |
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Miscellaneous |
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SW1 = DPDT switch SW2 = Push-To-On switch B1 = 12V car battery LS1 = 8Ω, 0.5W loud speaker |