Arduino custom wireless keyboard

There is a video associated with this repo, I highly recommend you watch it if you are going to use this repo.

How to use

*Installed directly from the Arduino library manager.

This is the micro-controller (MC) that will be running on battery and where all the buttons will be connected to. This needs to be a low current consuming MC and one that ideally meets the number of inputs pins to match the number buttons you are going to have.
I highly recommend the Attiny MCs, such as the Attiny85 (8 pins), Attiny84 (14 pins), or the Attiny88 (28 pins).
Changes you need to make to the code (/transmitter):
- The CE and CSN pin numbers to match your connections, these could be any GPIO pins in your MC.
- MAX_SHORTCUT_KEYS, this is the maximum number of characters a keyboard shortcut/sequence can be. This is specified so only the required number of bytes are sent through the radio signal.
- The BUTTONS_INFO array. Each button element is made up of two values, the first is the pin number the button is connected to your MC. The second is a string of characters seperated by spaces. The characters are represented by their decimal/int values, which can be found here and here. Make sure you don't go over your MAX_SHORTCUT_KEYS in the string of keys, if more keys are required, simply increase MAX_SHORTCUT_KEYS.

Any MC can be used here with USB cable connection, and one that has HID support so you can easily use the Arduino Keyboard library with no issues. I recommend the Pro Micro MC.
Changes you need to make to the code (/receiver):
- The only change you need to make is if you changed the MAX_SHORTCUT_KEYS in the transmitter side, if you did, make sure the MAX_SHORTCUT_KEYS matches.

Please refer to the /3d_models directory.

The Attiny MCs can be programmed just like any Arduino and it's very easy to upload code to them.
You just need a USBASP adapter, then simply make the connections as shown in the image below.

You will also need to install the Attiny boards using the AttinyCore board manager by placing this link http://drazzy.com/package_drazzy.com_index.json to your "Additional Boards Manager URLs", which can be accessed in File > Preferences.
From Tools > Board, choose your Attiny board with the no bootloader option.
Then go to Tools > Programmer and choose USBasp (ATTinyCore), and then press Tools > Burn Bootloader.
Then to simply upload code, use Sketch > Upload Using Programmer.
You can use stripboards with some wires to make uploading code to the Attiny MCs more convenient: