IR proximity sensor relay switch

Discussion in 'The Projects Forum' started by sanok, Sep 24, 2013.

  1. sanok

    Thread Starter New Member

    Sep 24, 2013
    2
    0
    Hi everyone.
    I'm trying to control a relay with Sharp IR sensor
    [​IMG]
    Relay and sensor can be powered by 5V. The problem is that sensor's output varies between 0.2V-2.5V (depends on distance from reflective surface) and this is too low or too high for transistor's base.
    Any other solution?
    Thanks for any help.
    [​IMG]
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,565
    2,379
    What is the part No? Or do you have a spec sheet?
    Often these retro-reflectors are Open Collector and switch 0-5v, unless the output is directly from the sensor itself.
    Max.
     
  3. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    Using comparator as LM393 and to set a reference voltage as 0.2V or othe r voltage you want, LM 393 needs a 10K pull up resistor, this is a trigger signal.

    1. Adding a NE555 monostable to get a delay time.
    2. Adding a CD4013 flip flop to get a toggle switch.

    If the current of relay less than 70mA, then ne555 can sink or output the current, if you using CD4013 then you have to using a bjt to drive the relay.
     
    sanok likes this.
  4. sanok

    Thread Starter New Member

    Sep 24, 2013
    2
    0
    Here is data sheet

    http://www.sharpsma.com/webfm_send/1542

    Thanks Max
     
  5. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    how about a comparator with an adjustable reference from a pot, so you can adjust the trigger distance?
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,565
    2,379
    You really need a N.O. or N.C. type output, with analogue type output you will need one of the solutions already mentioned.
    Or a LM311 comparator set for the minimum signal.
    Max.
     
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