IR Remote

[last updated: 2023-12-06]
IR Remote Control Codes
TV antenna - rotating
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• NOTE: This project abandoned. It was a good exercise, and I may pick it up in the future for other purposes,
  but it only cost $10 for a Universal Remote to replace my defective one, so that's what I did.
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• Using an arduino to emulate a TV IR remote control:
• IR remote controls ("clickers") have an IR-emitting LED, that is pulsed (PWM modulated) at a frequency of 38 KHz.
  Pressing different buttons on your remote will always send out a 38 KHz pulse train,
  but different keys will produce pulse trains of different lengths (measured in ms or us).
  Measuring the length (time duration) of the received pulse train can therefore differentiate between different button-presses.
• The receiving module on the TV or light bulb (or whatever device is being controlled)
  has an LED receiver chip that contains demodulation circuitry and will only respond
  if it is receiving 38 KHz pulses.
  The receiver chip will have an output pin that will toggle if it is receiving 38KHz pulses, or not.

  
  External circuitry monitors the output pin and measures the length of the 38 KHz pulse train
  in order to identify the button that was pressed on the remote. (this is surely over-simplified...)

• The procedure for this project is to first build a circuit with an LED receiver chip
  that will receive and decode button-presses from the IR remote you wish to duplicate.
  This "mapping" will be used to identify which button has been pressed.
  Then build a circuit with an IR LED that will send out pulses, programmed per the mapping of your existing remote,
  with the desired pulse-length to emulate the button-presses desired.
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• Hardware:
  • Adafruit 388 - super bright 5mm IR LED:

  • Adafruit 157 - TSOP38238 IR receiver:
    NOTE: different TSOP models have different pinouts. Check your datasheets.
    
    • from Adafruit (https://learn.adafruit.com/ir-sensor/ir-remote-signals):
      contains a demodulator that detects modulated IR at 38 KHz (a PWM signal blinking at 38KHz).
      IR detectors are digital output:
      they output LOW (0V) if they detect a 38KHz-modulated IR signal,
      and they output HIGH (5V) if they do not,
      ie. their output is reverse logic

  ---------------------------------------------------------------

• The Project Proceeds ...
  • IR sensor function test:
    • First breadboard an IR receiver chip and demonstrate
      that its output toggles when it receives 38 KHz signals from an existing remote.
    • This can be done without an MCU, since the IR receiver chip output can directly drive an indicator LED.
      
      
      test with Direct Wire
      
      
      test WITH Arduino
      • Or it can be done With an MCU, which is what I did successfully with arduino program: IR_LEDsensorTest.ino

    • Decode signals from existing remotes:
      • Requires the IRremote library.
        3.6.2 available: https://github.com/Arduino-IRremote/Arduino-IRremote
        3.6.1 Added with Library Manager
        After some editing for new library version, it worked, (IR_LEDsensorDecode.ino)
        printing out two, 8-hex-char numbers for each keypress on the remote.
            See: IR Remote Control Codes

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  • Links:
    • https://circuitdigest.com/electronic-circuits/ir-transmitter-and-receive...
    • https://cdn-learn.adafruit.com/downloads/pdf/using-an-infrared-library.pdf
    • https://www.instructables.com/Make-Your-Own-IR-Remote-That-Can-Reach-Any...
    • https://www.instructables.com/Arduino-IR-Remote-receiver/
    • https://www.electronicshub.org/diy-universal-remote-using-arduino/
    • https://create.arduino.cc/projecthub/electropeak/use-an-ir-remote-transm...
    • https://techzeero.com/arduino-tutorials/control-tv-with-an-arduino/
    • https://howtomechatronics.com/tutorials/arduino/control-any-electronics-...
    • https://www.thegeekpub.com/18493/setup-an-ir-remote-for-an-arduino/
    • https://www.pjrc.com/teensy/td_libs_IRremote.html
    • http://www.righto.com/2009/08/multi-protocol-infrared-remote-library.html
    • http://www.righto.com/2009/11/controlling-your-stereo-over-web-with.html

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