Infra-red detector circuit

  
This circuit is a simple IR detector for testing IR remote controllers. The circuit is based on one phototransistor which receives the IR beam. The NPN transistor works as an amplifier which feeds current to the led. When this circuit detects IR or light, the LED is on. So you need to shield the phototransistor from ambient light if you don't want to do your tests in the dark. The best way is to fit the phototransistor in a small black tube. I used 2 cm long piece of insulating tube and fitted the phototransistor into the middle of the tube.
Infra-red detector circuit - schematic

Brief description of operation: Detects IR signals from TV remote controllers Circuit protection: No special protection needed Circuit complexity: Very simple and easy to build, no need for circuit board Circuit performance: Not very good, detects IR remote controller signals nicely at 10 cm distance, also sensitive also to normal light and can't be used on bright light to detect IR remote controller signals Availability of components: Original components might not be available everywhere, suitable components for modificantions Design testing: Built quickly from the parts found on my lab, the first prototype was usable, few different photosensitive transistors tried Applications: IR remote controller testing, detecting IR beam, testing of phototransistors Power supply voltage: 9V battery Power supply current: less than 1 mA on darkness, up to nearly 20 mA on bright light Component cost: Few dollars. If you own a video camera you can use it directly for viewing the IR signal from the remote control. Just point the remote control to the video camera and you sould see some flickering light in the video screen/viewfinder. This works because the CCD elements in the modern video cameras are also sensitive to IR radiation also. This ideas works with most of the video cameras but might fail on some (because some older cameras did not use CCD element and some new video cameras can have very good IR filtering in them). I...



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