Help with Optical sensor

Discussion in 'The Projects Forum' started by spelcaztr, Dec 19, 2011.

  1. spelcaztr

    Thread Starter New Member

    Feb 16, 2011
    Hi guys. I have been working on my project. Something that could detect incoming intruders in the house. is there a way to make an optical sensor to detect as far as 1m? I looked up some of the sensors in the market but a lot of them can only detect as far as 2mm. Or is there a better way? The sensor output should be able to activate a relay in so the output should be approximately 6v min.

    i think this works but it functions as a sound/tone detector or something.
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    The receiver is tuned to only respond to incoming infrared light modulated at the specified frequency, since he says tone I assume it's audio frequency. It could work like a light barrier. Which brings us to a fundamental question.

    Do you want to detect someone approaching or do you want to detect someone passing through a light barrier?

    One works with reflection, the other one on interruption of a light beam (pulsed or continuous).

    Ambient light sources can be a quite challenging issue to resolve. Is this going to be installed where ambient light changes rapidly? (like direct sunshine with passing by clouds)

    Have a look at the SI1102. You might be better off with ultrasound modules.
  3. Adjuster

    Late Member

    Dec 26, 2010
    I've seen barrier alarms working indoors really well using a sender and receiver pair pointing at a corner reflector (prism type, like the ones on vehicles). I think the optics use collimating lenses though. Security companies must use loads of these things.
  4. Bernard


    Aug 7, 2008
    Passive infra red, PIR, detectors are quite reliable, & good for several meters.