pico-ir-keyboard

Add IR remote as input to any PC

• Decoding NEC protocol IR pulses from remote control with a Pico and perform keypress as a USB keyboard (HID).

To compile pico-ir-keyboard

1. Set up your PC to point to use the Raspberry Pi Pico SDK, follow README in Raspberry Pi Pico SDK.
2. Clone this GitHub repo

   $ git clone https://github.com/gharishkumar/pico-ir-keyboard.git
   

3. Change to pico-ir-keyboard directory.

   $ cd pico-ir-keyboard
   

4. Setup a CMake build directory. For example, if not using an IDE:

   $ mkdir build
   $ cd build
   $ cmake ..
   

5. Make your target from the build directory you created.

   $ make -j4
   

6. You now have pico_ir_keyboard.elf to load via a debugger, or pico_ir_keyboard.uf2 that can be installed and run on your Raspberry Pi Pico via drag and drop.

NOTE :

• IR rx pin, IR command (or) Keyboard keycode can be customised in pico-ir-keyboard/src/main.c.
• By default GP27 is set as INPUT.

Back story

• It all started with adding IR remote support for Raspberry Pi 3 Model B+ with custom embedded Linux for Web Kiosk ( I know Raspberry Pi GPIO can decode IR. I have also decoded NEC protocol with Python in Raspberry Pi OS ).
• I have no patience in recompiling the OS with GPIO and Python.
• I thought it would be easy to add Raspberry Pi Pico to emulate the keyboard (USB HID). As the website already has keyboard support.
• I also found a product by Adafruit pIRkey which does the same, but they discontinued it.

Adding HID

 ✔️ It's a relatively simple and easy process available with TinyUSB, via CircuitPython, Arduino IDE (or) Raspberry Pi Pico SDK.

 ❌ but not MicroPython.

Decoding IR with pico

1. Try old python code.
   • Moving on, I realised that using Raspberry Pi Pico to decode IR NEC protocol and emulate a keyboard is not that easy.
   • The previous program I used to decode IR NEC protocol in Raspberry Pi 3 Model B+ Python did not work in either MicroPython or CircuitPython.
   • In both time differences between two pulses returned zero.
2. Search for Pico specific code.
   • I found micropython_ir by peterhinch in MicroPython it 🎉 works great in decoding IR NEC protocol.
   • It uses IRQ, so no chance of running it in CircuitPython.
   • By default, MicroPython doesn't support HID for Raspberry Pi Pico.
   • I tried including HID in the MicroPython source and compile it but had no luck; I should try that in the future.
3. Changing the old code to C.
   • As USB HID support is available in Arduino IDE, I convert that old Python code to C.
   • It didn't work either.
4. Trying with PIO.
   • So, I decided to convert that Python code into PIO assembly language to include it in CircuitPython.
   • After some searching, I found the same in a pending pull request by mjcross with PIO in Raspberry Pi Pico SDK Great!
   • Then decided to go with Raspberry Pi Pico SDK.

Merging two

• Merging is simple with the device examples provided in TinyUSB and from the pending GitHub pull request.