IR Remote Tester Helps You Crack The Code

IR Remote tester in use, showing a remote control lighting up an LED and screenshots of the Arduino serial terminal

Even though some devices now use WiFi and Bluetooth, so much of our home entertainment equipment still relies on its own proprietary infrared remote control. By and large (when you can find them) they work fine, but what happens when they stop working?  First port of call is to change the batteries, of course, but once you’ve tried that what do you do next? [Hulk] has your back with this simple but effective IR Remote Tester / Decoder.

IR remote tester schematic showing arduino, receiver, LED and resistor
How to connect the TSOP4838 to an Arduino to read the transmitted codes

By using a cheap integrated IR receiver/decoder device (the venerable TSOP4838), most of the hard work is done for you! For a quick visual check that your remote is sending codes, it can easily drive a visible LED with just a resistor for a current-limit, and a capacitor to make the flickering easier to see.

For an encore, [Hulk] shows how to connect this up to an Arduino and how to use the “IRremote” library to see the actual data being transmitted when the buttons are pressed.

It’s not much of a leap to imagine what else you might be able to do with this information once you’ve received it – controlling your own projects, cloning the IR remote codes, automating remote control sequences etc..

It’s a great way to make the invisible visible and add some helpful debug information into the mix.

We recently covered a more complex IR cloner, and if you need  to put together a truly universal remote control, then this project may be just what you need.

15 thoughts on “IR Remote Tester Helps You Crack The Code

  1. Or, grab pretty much any phone camera, open the camera program and point the camera lens at the remote control as you press the buttons… you’ll see the LED on the phone’s screen flash since the CCD is partially sensitive to IR.

    While a dedicated device like this is a great option, you might find you already possess a device capable of telling you this information on your person already.

      1. my iphone 13 (faintly) shows the IR led flickering on both back- and front camera. If you do the check in a dark environment there is not problem to see if the remote id still working

  2. Look up JP1 remotes. There was a brand of universal remotes that had a 6 pin 0.1″ pin header (or holes to solder one) inside the battery compartment. For many of them it was possible to make a parallel port programming cable from a DB25 connector, some wires from a floppy or hard drive cable, a couple of resistors and a 6 pin IDC. Later remotes required a slight more complicated programming cable, and schematics were provided for LPT and USB.

    There was a custom Excel spreadsheet one could use to create the data to upload to JP1 remotes to make them operate equipment for which they didn’t have data pre-programmed.

    If you had a learning remote with JP1 you could save the data from another remote then remap it how you wanted. My contribution was getting the data from a remote for a fancy stereo receiver that had a ton of AV input and outputs, but was made circa 1995 or 1996. For that brand, none of the universal remotes supported any model made prior to 1997 – when a DVD input was added to their entire product line and the manufacturer changed most of the data the remotes sent out.

    1. I might still have some 2k rom chips around from when I used to upgrade those. Some of the DirecTV remotes were also JP1.

      I really miss my Galaxy Note4 IR blaster. I had an app that would just do any codes. Not be a full screen gory add I didn’t need for TV shows I’m never going to watch like the OEM bloatware.

      It was great for turning down the TV at restaurants and getting grandma’s TV to some sane aspect ratios.

  3. search ebay for “L336 Universal Smart Remote Control With Learn Function” these are so cheap and can learn just about anything even different carrier frequency codes. maybe someone will reverse engineer this to find out how the Chinese do it…

  4. Does the detected data contains the device’s (like a tv) code?

    I’ve a no name tv that I want to program my universal remote to control it but I can’t find it’s code any where.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.