Everyday addiction of people towards technology is growing deeper and deeper, even before entering into someone’s house we press door bell which is a clear example to support our belief. Listening same door bell always might be boring, this circuit 12 tones door bell help us to avoid this dull situation.
Music door-bells, music horns, touch sensitive door-bells etc are not new projects electronics hobbyist, especially for BEP readers. But, this music producer (twelve popular tones in sequences) gives a new dimension to musical door-bells. Whenever a switch is pressed, a popular tone pops out to refresh our mind. Using the circuit we have prepared here 12 different tones can be heard in sequence.
Circuit description of 12 tones door bell
The heart of the circuit 12 tones door bell incorporates integrated circuit UM34815A (IC1). This integrated circuit falls in the group of door-bell IC chips. The IC1 is a 10-pin DIL (dual in line) package IC. It contains a ROM with 512 musical notes, 6 tone generator, rhythm generator, modulator, oscillator, frequency divider and pre-amplifier. In the circuit of 12 tone door bells, very few components have to be externally connected to set up the timing of built-in oscillator and to build an external AF amplifier/driver circuit.
The circuit of 12 tone door bells starts operating as soon as the switch SW1 is pressed and then the tune is played in an ascending order serially i.e. song tune-1, song tune-2 etc.
Transistor T1 (SL100A) is used as an amplifier-driver connected with pre-amplified output of the chip from pin 11 to drive any 8-ohm or 4-ohm speaker directly. The speed of the tune being played can be changed by varying the value of resistor R1.
Battery B1 is used to supply the input voltage in the circuit of 12 tone door bells.
By adjusting the value of capacitor; C1 and resistor; R1, more notes can be played as per the need.
PARTS LIST OF 12 TONES DOOR BELL
Resistor (all ¼-watt, ± 5% Carbon)
R1= 100 KΩ
R2 = 15KΩ
C1= 47 pF (Ceramic Disc)
IC1 = UM34815A(operational amplifier)
T1 = SL100A (NPN transistor)
LS1 = 4Ω OR 8Ω speaker
B1 = 3v Battery