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

Libraries needed

*Installed directly from the Arduino library manager.

• RF24 by TMRh20.
• Button by Michael Adams.

For the transmitter

• 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.

For the Receiver

• 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.

For 3D printing

Please refer to the /3d_models directory.

Components

Wiring

Transmitter

Receiver

How to upload code to Attiny MCs

• 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: