This infrared light controlled 12-tone musical bell can be operated using any TV remote control. It can be operated from up to 10 metres, provided the remote control is directed towards the sensor.
Musical bell circuit
The circuit uses the popular 3-lead IR sensor TK1836 to trigger musical bell built around IC UM3481(IC1). (You can also use IC UM3482, UM3483, or UM3484 in place of IC UM3481.) The sensor responds only to 36 kHz. Most TV remote controls transmit this frequency.
When any button on the TV remote control is pressed, the sensor’s output pulses low. Transistor T1 conducts to apply a triggering pulse to IC1 at its pin 4. After playing one musical tone, the circuit automatically resets. If you again press any of the remote’s buttons, another music is heard. This way, twelve different musical tones can be generated.
The circuit works off a 5V power supply. Regulator IC 7805, powered by a 9-12V DC source, provides regulated 5V.
The article was first published in November 2009 and has recently been updated.