This infrared detector can be used to detect the presence of modulated infrared signals in its vicinity from any electronic source, for instance, an IR handheld remote controller. It can also be used for testing infrared burglar alarm systems. This is not an infrared motion detector.
The IR detector circuit in principle, converts the IR signal pulse trains into noticeable aural notes. S1 is used to switch on/off mains power and LED1 indicates power-on. Resistor R4 and zener diode ZD2 form a low-current voltage stabiliser for providing steady 5.1 V DC to the small signal preamplifier circuit. IR LED1 is the main sensing element.
The infrared signal detected by IR LED1 is amplified by npn transistors T1 and T2. The amplified signal is fed to the melody generator via resistor R5. The output of the melody generator UM66 is fed to LM386 low-power audio amplifier (IC2) via variable resistor VR1, which works as the volume control. The loudspeaker sounds to indicate the presence of IR signal near the circuit.
IR Detector Circuit
The infrared detector circuit can be easily wired on a small veroboard or any general-purpose printed circuit board.
Pin configurations of IC LM386, transistor BC547 and melody generator UM66.
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