2B-16 TUNE MUSICAL BELL
This project can be used as door bell also. This can be used when the car is being back or reverse as well as in intercoms.
TECHNICAL DESCRIIPTION AND WORKING:-
This project has been developed and successfully tested OK in TV Engineer Technical Lab.
Now a days the spring system door bells are out dated and replaced by a variety of musical bells. We are now introducing a 16 tune musical bell to you. This bell is being used in houses as well as in the form of horn in the motor vehicles.
The circuit of such a bell is given below. Since it works on 3V DC as well as 220V AC, it is known as AC/DC bell also. The circuit employs one integrated circuit IC 34815A; transistors BEL 187 [TR1] and BC158 [TR2]. This IC produces 16 different tunes based on Hindi Music through its oscillator. In addition the IC has also inbuilt mechanism of one system generator, one pre-set timer which stops the sound on a fixed interval and an amplifier.
You can operate this bell on 3 V DC as well as 220V AC as shown in the diagram above. Pin 2 & 3 of IC 34815 and emitter of transistor TR2 is fed with 3V supply and pin no. 5 and 8 of the IC and emitter of TR1 are earthed. When pin no. 16, through a resistance R1 10K 1/2W is touched with pin no. 4 of IC through a diode D IN 4007, the IC oscillates and the output is derived through pin no. 10. This output bell signal is again amplifed by TR2 BC158 and given to speaker through capacitor C5 100mfd/12V. This circuit is given feed through the network of R7 470K and TR1 BEL 187.
PRECAUTIONS WHILE ASSEMBLING THE PROJECT:-
- Mount IC on IC base.
- Pay attention to collector,base and emitter of transistor while mounting.
- Check polarity of capacitor and diode.
- Please use resistance of the exact value as given in the circuit.
- Check short circuit while soldering.
LISTS OF COMPONENTS
R1 10K 1
R2 150K 1
R3 39K 1
R4 270K 1
R5 330K 1
R6 33K 1
R7 470K 1
C1 3.3 mfd/12v 1
C2,C4 .1 mfd 2
C3 47 pf 1
C5 100 mfd/12v 1
TR1 BEL 187
D1 IN 4007
IC 34815 A
Speaker, IC base, Cell Tray, PCB, Solder, Switch, Flexible wires etc.