#074 Raw Arduino Infrared

Tests raw IR reception.

Notes

An exploration of IR Sensor reception based on the adafruit sample code available here.

I’ve cleaned up the code a bit and modified it to optionally pump data out for plotting with LEAP#090 PlotNValues (a simple Processing sketch). This provides a simple graphical illustration of the PWM characteristics of IR protocols.

Here’s a sample trace of the “0” key being pressed on a common MP3 player remote control:

And another showing an LG remote control “power on/off” key press:

This all got me reading IR Remote Control Theory to better understand operation and protocols. Next step is to start decoding the signals, however for that I might avoid re-inventing the wheel and instead try the IRremote library.

Construction

Credits and References

• IR Remote Control Theory - the best reference I’ve found so far for IR theory and also protocol details.
  • originally http://www.sbprojects.com/knowledge/ir/index.php
  • now offline, but available at archive.org
• Using an IR Sensor - a good IR tutorial that this project is based upon
• TSOP1838 datasheet - one of many similar IR sensors
• Port Registers - explains Arduino raw port methods
• IRremote library - an IR library (not used here)