

Car Reverse Horn
Here is a simple project “Car Reverse Horn”, can be used in car as reverse horn i.e. produce sound when car is moving in reverse direction.
Circuit description
The heart of car reverse horn circuit is melody generator IC CIC2877 (IC1) followed by amplifier IC and few passive components. IC1 is made from a ROM oscillator and a pre-amplifier which further generate sound. The generated sound output is available at pin 3 which is further connected to pin 2 of amplifier IC through variable resistor VR1. IC2 amplify the generated sound up to desired level and its output from pin 7 and 12 is given to loudspeaker through coupling capacitors C8 and C9 respectively. The power supply ig given to the circuit from battery of car.
PARTS LIST
Resistors (all ¼-watt, ± 5% Carbon)
R1 = 1.5 KΩ
R2 = 1 KΩ
R3 = 120 KΩ
R4, R5 = 1 Ω
Capacitors
C1 = 10 µF/25V (electrolytic)
C2 = 1 µF/25V (electrolytic)
C3 = 100 µF/25V (electrolytic)
C4 = 0.01 µF (Ceramic Disc)
C5, C6, C7 = 47 µF/25V (electrolytic)
C8, C9 = 470 µF/25V (electrolytic)
C10, C11 = 0.1 µF (Ceramic Disc)
Semiconductors
IC1 = CTC2877 (Melody Generator)
IC2 = AN7148 (Amplifier IC)
Miscellaneous
LS1 = 8 Ω loudspeaker
Dear Sir – two capacitors are shown as C 1 . Values are different . C1 may be near R2 and C2 may be near VR1.l clarify.