Wireless and Advanced Controllers
While most custom keyboards are wired, the dream for many is a fully custom, fully wireless mechanical keyboard. This is made possible by a new generation of microcontrollers with built-in Bluetooth capabilities. These controllers, combined with power-efficient firmware, allow you to build a clean, cable-free setup.
Wireless builds come with their own unique considerations, from power management to firmware choices, but the freedom they provide can be well worth the extra complexity.
The King of Wireless: nice!nano
The undisputed leader in the wireless keyboard space is the nice!nano. It is a small development board that is pin-compatible with the Pro Micro, meaning it can be used as a drop-in replacement on many PCBs, especially on split keyboards.
- Core Technology: The nice!nano is powered by the nRF52840 microcontroller, which is a powerful ARM Cortex-M4 chip with built-in Bluetooth Low Energy (BLE) support. BLE is crucial for maximizing battery life.
- Firmware: It is designed to be used with ZMK Firmware. ZMK is built from the ground up for wireless functionality and is extremely power-efficient, allowing a keyboard to run for weeks or even months on a single battery charge, depending on the battery size and features used.
- Power: The nice!nano includes built-in battery charging circuitry. You simply connect a small LiPo (Lithium-Polymer) battery to the designated pins, and the board can be charged over a standard USB-C cable while still being used. It manages the charging process safely, which is critical when dealing with LiPo batteries.
Considerations for Wireless Builds
Building a wireless keyboard introduces a few new challenges:
- Power Consumption: Every component choice matters. Features like RGB lighting and OLED screens are a huge drain on the battery and are generally avoided in wireless builds where longevity is a priority. ZMK's documentation includes a Power Profiler tool to help you estimate the battery life of your planned build.
- Case Material: Bluetooth signals cannot easily pass through metal. For a reliable wireless connection, you need a case made of a radio-transparent material like plastic, acrylic, or polycarbonate. Full aluminum cases will block the signal, making them unsuitable for wireless builds unless they have a non-metallic window for the antenna.
- Batteries: You'll need to source a LiPo battery and find a safe place to house it within your keyboard case. It's crucial to use a battery with the correct voltage and polarity and to ensure it's protected from being punctured or crushed.
- Switches and Sockets: While not a controller issue, it's worth noting that hotswap sockets are highly recommended for wireless builds, as desoldering a switch on a board with a battery can be more hazardous.
Controllers for Split Keyboards
Split keyboards present a unique challenge: the two halves need to communicate with each other.
- Wired Split: The most common method is to use a TRRS (Tip-Ring-Ring-Sleeve) or TRS cable to connect the two halves. One half acts as the "master" and is connected to the computer via USB, while the other "slave" half sends its keypresses to the master over the TRRS cable. This communication is typically handled via a serial or I2C protocol.
- Wireless Split: In a truly wireless split keyboard, each half has its own controller (e.g., a nice!nano) and its own battery. The two halves communicate with each other wirelessly via Bluetooth, and only the master half (usually the left side by default) communicates with the host computer. This is one of the most complex but also one of the most rewarding types of keyboards to build, offering the ultimate ergonomic and minimalist setup. ZMK is specifically designed to handle this wireless split communication seamlessly, with advanced power management and connection reliability features.
The world of controllers is constantly evolving, with new and more powerful chips enabling ever more exciting features. Whether you're building a simple wired board or a complex wireless split, the controller is the key to unlocking its full potential and determining your keyboard's capabilities.
This concludes our section on controllers. Now it's time to put it all together as we look at Assembling Your Keyboard.
External Resources