Test unit for IR remote controllers - produces audible signal related to received IR signals

摘要

The Infra-red signal from the remote control unit is detected by a photodiode (D1). The a.c. component of the signal is coupled via a capacitor (C2) to one input of an operational amplifier (IC1). The other input to the amplifier is fed by a resistive divider chain (R1, R2, R3), via an RC filter (R4, C1). A proportion of the diode output signal is fed via a resistor (R5) to the divider chain. The output of the amplifier is fed via a driver transistor (T1) to a loudspeaker. The 'salvoes' of digital pulses from the controller occur at rates which range from two to 30 times per send. After some practice, the user can listen to the resultant sound and determine if the controller is working correctly. @(8pp Dwg.No.1/2)@.