Here is the remote control tester circuit. This circuit is really a simple and easy tester for verifying the basic operations of an infrared remote control unit. It is low-cost and very easy to construct.

The tester is designed around infrared receiver module TSOP1738. Operation of the remote control is identified by a tone from the buzzer. The circuit is sensitive and has a range of about 5 metres. The integrated IR receiver detects, amplifies and demodulates IR signals from the remote control unit. The piezobuzzer connected at its output sounds to tell us the existence of transmission from the remote control unit.

As displayed in above circuit diagram, output pin 3 of IR receiver module TSOP1738 (IRX1) normally stays high and the piezobuzzer is in silent mode. When the IR module IRX1 receives an infrared signal, its output is going low and, because of this, the piezobuzzer sounds to signify the reception of transmission from the remote (for example television remote control unit).

Power supply for the circuit is taken from the mains making use of a capacitive potential dropper, a half-wave rectifier, a shunt regulator and related parts. Ensure that capacitor C1 is of X2 type. Work with a appropriately small enclosure for making the unit handy.

Assemble the circuit on a general purpose PCB and enclose inside a box. Ensure that the IR receiver module is positioned around the front panel of the box/cabinet so that it can get the IR signals easily. Well, before soldering/connecting the shunt regulator and IR module, please check up the following TL431 and TSOP1738 pin configuration.