Arduino's designers made it to be accessible to people at all skill levels, and Kaleidoscope is built on top of the Arduino platform because we share that goal. The easiest way to customize your keyboard's firmware is to use the Arduino IDE. Even if you expect to use the command line to compile your firmware, you'll still need to install Arduino, as they provide the compilers and libraries Kaleidoscope needs to work.
Using the IDE is is the easiest process for folks who are new to Arduino, or to programming generally. If you follow the instructions below step by step you should be fine. :-)
The right way to install Arduino is a little bit different depending on what operating system you use.
As of this writing, the latest version is v1.8.13, which you can download from https://www.arduino.cc/download_handler.php?f=/arduino-1.8.13-macosx.zip
1. Install version 1.8.13 or newer of the Arduino IDE from http://arduino.cc/download. Unfortunately, the version packaged in Ubuntu is too ancient to support Arduino's new way of doing 3rd-party hardware.
3. On some linux distributions, ModemManager can prevent you from flashing or updating your keyboard by interfering with its virtual serial port. Additionally, by default, you may not have permissions to access your keyboard's serial port. `udev` is the Linux subsystem that managed both of these things. You should install our udev rules to manage access to your keyboard's serial port.
1. If you want to flash your firmware as non-root, ensure your user has write access to the appropriate USB devices in devfs. By default, the devices are owned by `root`:`operator`, so put yourself in the `operator` group. You will also need to add yourself to the `dialer` group to use the modem device: