Intro

I received an old TV, but it had no remote control. I looked in my drawers and I had loads of old remotes, none of which of course would work with the TV. However, I thought it was a shame to let all those go to waste, and I realized that if only I knew what codes they were sending, I could then use them in other projects.


What you need for this project:

What	img	price in 2020
Esp32		7€
Nano		4€
IR Receiver		5€
Display		6€
Relay		3€

Links are not an endorsement of the product and just provided for convenience sake. I get not cut.

Decoding

The design is rather simple: An IR receptor connected to a board, and the board connected to a display.
After that, it is just a matter of pushing each button on the remote and take note of the code received by the decoder. More tedious than difficult :-).
I bought a lot of ESP32 for other projects, but it is a bit of overkill, in the sense that you don't need any of the wifi or bluetooth capabilities, so a Nano would do just as well. It was also an opportunity for me to code for the Nano. That's why I listed both prices. You don't need both, any of the two will do.
(For the heck of it, I also decided to send the result via bluetooth to my Pebble with the esp32, but that's outside the scope of this doc).
The wiring looks like this:

Lessons learned

• First problem was to get the code to the Nano! Turns out a Nano is not necessarily a Nano. There is
  * the first generation using the ATMega168 chip,
  then
  * a second generation using the ATMega328p (old bootloader),
  and
  * a third generation using the ATMega328p (new bootloader).
  Luckily the Arduino IDE supports them all.


• Read the doc ! I spent a lot of time trying to figure out why my Oled display didn't work, until I realized I was trying to use the arduino ssd1306 library with a chip that was NOT an ssd1306. Once I loaded the SSH1106 library - or rather a library that supports the ssh1106,things started getting better. (found another one later).


• Only started to get better, because the graphic library uses more memory than the nano can afford, so the whole thing was very unstable. I dug deeper, and found out the library had a text only mode (u8x8), which wasn't so memory hungry and would work with the nano.


• Next hurdle was to find a font small enough for the screen, as most documented fonts were for the graphic mode.


• All in all spent more time trying to display the results on the oled screen than actually getting them- this was very straightforward !!!


• And finally: forget the Nano! Unless you're really tight, or your project doesn't need an Oled, add another €2-€3 to your project and use an esp32. You don't need the wifi capabilities, but the small memory of the Nano complicate your life if you intend to use a Oled screen with it-at least a ssh1106- based.( I'm glad I did it for the challenge, but considering the price difference with other boards these days, there is no reason to submit yourself to that !)

(And before you ask: the container is half a plastic milk bottle. There is a hole in the cap that lets the usb cable thru, and the top is masked with duct tape, the screen and the sensor are above it, and then I used cling film to protect them. Quick and dirty, dirty being the operative word here :-)


Once I had a bit more time, I re-did the box to separate the Oled screen from the rest, the rationale being that I can reuse the screen for other projects.

Going further

Once I have the codes, I can use the remote for my own purpose.
The most obvious one is to switch things on and off.
For that, all you need is a relay switch coupled to a board, coupled to an IR receiver.

Alternate designs:

1. Use 2 ESP32 (or ESP8266), one connected to the IR receiver (A), another connected to the switch (B). When A receives the code from the remote, it sends it via internet or local network to B, which switches ON or OFF.
2. Bypass the remote altogether :-) Have a simple website/phone app with buttons which then sends the code to the ESP attached to the relay.
3. Use telegram to send the code to the ESP attached to the relay.

Both cases are equally good if the device you want to switch on and off is located outside of the reach of the remote (usually 5-10 m.). That can be in another room (basement, attic), or even in the garden (assuming your network reaches that far).



From a programming point of view, all the information needed is here: IR library, ESP8266 example.     Adaptation for an ESP32 or Nano is straightforward.

Since then, I have found the Linux Infra-Red Remote Control (LIRC) project and the windows equivalent, which have most of the existing remote codes.

Here is another fun project with those remotes lying around: a calculator!





(C) Thunus F. 2020.