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
    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
    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.