The simplest possible circuit is to just drive an IR LED with whatever voltage source and an appropriate dropping resistor. Then the receiving end is a phototransistor with a series resistor on the collector and the emitter to ground. Connect up the base of a transistor through another resistor to the junction of the series resistor and the collector. Now that transistor will have current pulled away from it's base as long as the photo transistor receives light. Stick an IR filter on it and a tube to make it directional. That's about as simple as you can get. Your alarm is switched by the second transistor which stays off as long as the phototransistor receives light.
I also got that idea but ir phototransistors and photdiodes are very hard to get in my place.But tsop modules are available I even have a few tsop1838's with me . And now i'am looking for an ir detector which when detects coded ir light makes an led glow but not blink the problem with normal circuits are that the led blinks when it detects ir light.Please help me aaron
Help me my amplifier is on fire and my speaker is inside a beaker
A TSOPxxx is an IR receiver IC that is made by Vishay/Telefunken. It has a black coated photo-diode, amplifier, tuned filter, AGC, Demodulator and output transistor.
The internet has thousands of IR circuits that do not work and it has thousands of IR circuits that work perfetly. If this is a school project then your teacher wants you to study them and select a circuit that works.
need help
Posted - Mar 30 2010 : 02:19:51 AM
TSOP IR receiver.PNG