This is a project of an IR remote tester circuit with alarm. It can be used to test the output of any IR remote like TV, DVD player, audio player etc. The circuit will show a visual indication by activating an LED and a melody alarm when it will sense any IR. A TSOP1738 infrared sensor
is used to detect the IR signal. The infrared signal detected by the sensor goes at the base of the transistor making it switch ON and activate the LED and alarm. The alarm circuit is built with the UM66 CMOS melody IC. A 3V zener diode is used to step down the output voltage of the 2N3906 transistor to 3 volts to operate the UM66 IC. A BC548 transistor is used to amplify the output of the UM66 to drive an 8 ohms speaker. The operating voltage of the circuit is 6 volt DC.