Infrared Diode

Discussion in 'General Electronics Chat' started by sirch2, Feb 25, 2013.

  1. sirch2

    Thread Starter Senior Member

    Jan 21, 2013
    I'm looking to use an infrared LED and photodiode as a simple switch, i.e. turn the LED on and across the room the some other device turns on.

    I've read around the subject and there are some devices that need a 38kHz signal to for the receiver to respond but I cam across this deivce - - that would seem to be a simple photo diode.

    Questions are:

    • can that device work with out a 38kHz signal?
    • what would be a good circuit for switching based on that device?
    • are there any disadvantages (I assume the 38kHz is there to filer out environmental "noise" from other IR sources)?
  2. MrChips


    Oct 2, 2009
    It depends on how much reliability you desire.

    A simple IR LED and IR sensor will work but not very reliable.
    The next step is to drive the IR LED at 38kHz and use the appropriate IR detector.

    TV/VCR remote controllers use this scheme as well as they send digital data which can be checked for data corruption.
  3. sirch2

    Thread Starter Senior Member

    Jan 21, 2013
    Well, I figured it would work with the right circuit. As for reliability, it's not that critical in as much as the remote device either comes on or I need to send the IR pulse again. As long as it works most of the time it's not really an issue.

    Any thoughts on a circuit? One solution I'm thinking about is using the IR photodiode to control the base of a suitably biased transistor.
  4. crutschow


    Mar 14, 2008
    You can use most common photodiodes or phototransistors for your circuit.

    You will likely need a visible light filter (dark red) to avoid triggering from ambient light.