Here is a handy gadget for testing of infrared (IR) based remote control transmitters used for TVs and VCRs etc.
The IR signals from a remote control transmitter are sensed by the IR sensor module in the tester and its output at pin 2 goes low. This in turn switches on transistor T1 and causes LED1 to blink. At the same time, the buzzer beeps at the same rate as the incoming signals from the remote control transmitter. The pressing of different buttons on the remote control will result in different pulse rates which would change the rate at which the LED blinks or the buzzer beeps.
When no signal is sensed by the sensor module, output pin 2 of the sensor goes high and, as a result, transistor T1 switches off and hence LED1 and buzzer BZ1 go off. This circuit requires 5V regulated power supply which can be obtained from 9V eliminator and connected to the circuit through a jack.
Capacitor C1 smoothes DC input while capacitor C2 suppresses any spikes appearing in the input supply.
Proper grounding of the metal case will ensure that the electromagnetic emissions which are produced by tube-lights and electronic ballasts etc (which lie within the bandwidth of receiver circuit). The proposed layout of the box containing the circuit is shown in the figure. The 9- volt DC supply from the eliminator can be fed into the jack using a banana – type plug.