16 Tune Musical Door Bell, Voltage : 110V, 220V

The 16 Tune Musical Door Bell gives 16 different tunes by pressing switch sixteen times. This simple 16 Tune Musical Door Bell finds application as a doorbell as well as telephone intruder music player, toy or attention call bell. The heart of the circuit is an  APM993D named as IC1. IC APM993D is a programmed 1024 note ROM memory, which generates 16 musical tunes when it is triggered. The main feature of this IC is that it has inbuilt tone generator, rhythm generator, modulator, oscillator, frequency divider and preamplifier. So a very few number of components have to be connected externally to set up timing and to build an external AF amplifier/driver circuit.
About the circuit :
When switch is pushed on, voltage at pin 10 triggers IC APM993D. After triggering, IC plays a musical tone. 16 musical tones can be heard simultaneously on pressing sixteen times. Transistor T1 is used as an amplifier connected to chip preamplifier output at pin 14 to drive 8W loudspeaker. Resistor R1 controls the tempo i.e. the speed at which tune is played. Tempo can be varied as per choice by changing the value of R1.