16 TUNE MUSICAL DOOR-BELL
This simple circuit 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 gets 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.
ELECTRONIC HARMONIUM
The modern electronics presents this Electronic Harmonium as a hobby kit or people who are interested to have hands on experience in this field.
This harmonium can generate 15 different notes of music (one at a time). It has a PCB with 15 parallel copper strips. Each strip corresponds to one note. So as you put the probe on a strip, the instrument plays a corresponding note.
The circuit is build around IC1, which is used as a astable multivibrator. The frequency produced depend on the note selected by the probe. When we put the probe on different strips, we are effectively changing the frequency by changing the resistance between pin7 and pin2 of IC1.
MELODY GENERATOR
The BT8031 series are CMOS LSI chip is designed for use in doorbell, telephone and toy applications. They are on chip ROM programmed for musical performance produced by CMOS technology, these devices result in very low power consumption, since the BT8031 include oscillating and mode selection circuit, a compact melody module can be constructed with only a few additional components.
POLICE / AMBULANCE SIREN
Introduction:
There are different types of siren tones used for different purposes like ambulance, police fire etc. The siren kits available in the market generate normally a single tone. With multitone siren kit, we can generate different types of siren tones for different purposes. This unique feature of the circuit makes it versatile and useful in wide range of applications like burgler system, lift door open alarm, smoke detector and any other alerting application.
THREE TUNE MUSICAL BELL
The UM 66T series are CMOS LS is designed for use in doorbell, telephone and toy applications. They are on chip ROM programmed for musical performance produced by CMOS technology, these devices result in very low power consumption, since the UM 66T series include oscillating and mode selection circuit, a compact melody module can be constructed with only a few additional components.
TOUCH SENSITIVE MUSICAL BEL
This musical bell generates different musical tones every time the plate is touched. If the plate is touched for more than two seconds, it gives a sound (beep-beep) different from the musical tone. Musical tune is produced after removal of the hand touching the plate. Only a few additional components are required to achieve excellent results.