infrared emitting diodes sensitivity range ?

Discussion in 'General Electronics Chat' started by jimbowilly, Jan 21, 2012.

  1. jimbowilly

    Thread Starter New Member

    Jan 17, 2012

    When reading the datasheet of an infrared emitting diode.
    What would indicated the range in distance from the front of the diode within which the mechanics of the diode will be activated?
    Will a diode response be triggered at 3mm to 5 yards ? ...

    Thank you,

  2. Adjuster

    Well-Known Member

    Dec 26, 2010
    An infra-red emitting diode generates more or less of a beam of infra-red radiation. Some spread out fairly widely, others are narrower, more like a torch (flashlight) beam. Simple emitters just emit, they are not designed to detect as well.

    Are you talking about using a separate detector, or do you perhaps have one of those reflection sensors which has an emitter and a detector packaged together?

    Finally do you mean by "the range at which the mechanics of the diode will be activated" -are you talking about an alarm? Normally a detector has a stronger response as an emitter approaches, and some electronic device such as a voltage comparator is activated when the response gets large enough.
  3. jimbowilly

    Thread Starter New Member

    Jan 17, 2012
    I guess I am talking about an alarm.
    I have been reading about PIR's and digital infrared detectors.
    I'm interested in constructing a infrared security system for my home.

    I know it's most likely less expensive to purchase an existing system from a supplier.
    But. I am doing this just for the fun of it.

  4. crutschow


    Mar 14, 2008
    An IR LED is an emitter of light. It has no particular "range" or response point. The range is determined by the brightness of the light and the sensitivity of the light detector. The response range can vary from a few meters to kilometers, depending upon the transmitted light power and complexity of the circuit.