Infrared transmitter and receiver help

Discussion in 'General Electronics Chat' started by devpatel, Mar 24, 2013.

  1. devpatel

    Thread Starter New Member

    Mar 23, 2013
    1
    0
    Hey,
    I'm using infrared sensors instead of RF for cost issues but I am a bit confused about the whole concept.The idea is to tag vehicles with d infrared transmitter and place the receiver at the gate.The receiver is further interfaced with a micro controller.What i wanna know is whether i can get unique tags by just using IR RX-TX of different frequencies?Say 38Khz (TSOP1738) for small and 40Khz(TSOP1740) for heavy vehicles?Can the 38khz receiver accept 40Khz by mistake?How do i produce these two different frequencies(for IR transmitter) with 555?Can i get a range of about 2 feet?Thanks:)
     
  2. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    You can get a range similar to your TV remote control.

    No you can't normally use different IR modulation frequencies, as the 3pin IR sensors have internal "brains" that require a particular modulation frequency.

    What you need to do is the same as your TV remote, ie; modulate the 39kHz signal on/off in a pattern, and use a different pattern for each device.
     
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