Many vintage computer keyboards are desirable and collectible because they contain sturdy mechanical key switches — something that became less and less common as cheap membrane keyboards flooded the market. But not all vintage keyboards are good; many models from the ‘70s, ‘80s, and ‘90s were also cheaply constructed. That was true of the Apple Keyboard II, which came with the Macintosh Classic and Macintosh LC (not the Apple II series, which had built-in keyboards). Martin had a broken Apple Keyboard II gathering dust and decided to improve it with modern components.
Martin wanted to keep the original Apple Keyboard II enclosure, but nothing else was worth salvaging. The original keyboard featured rubber domes and a membrane sheet on the PCB. Not only did that provide a poor typing experience, but it also wasn’t durable. Martin’s goal was to reuse the enclosure with modern components while retaining the retro design aesthetic. Of course, that meant using quality mechanical key switches to ensure longevity and a satisfying typing experience. But doing so required a custom PCB on which to mount the new key switches.
Martin still had the original PCB, which made it easier to design the custom PCB. With that, he could take measurements to replicate the size and shape of the PCB, along with the key switch locations. The PCB’s traces form a standard keyboard matrix with diodes to prevent ghosting. An STMicroelectronics STM32F405 microcontroller monitors the keyboard matrix and runs QMK (Quantum Mechanical Keyboard) firmware, which allows for virtually unlimited customization of key maps, shortcuts, macros, and so on. A Nordic nRF52840 SoC acts as a Bluetooth adapter to connect the keyboard to computers, smartphones, and tablets wirelessly.
The PCB received Kailh hot-swappable key switch sockets, so Martin can switch out key switches whenever he wants. The key switches snap onto a custom key plate, and then plug into the sockets. The key caps look appropriate for the era and the only obvious sign that this isn’t a vintage keyboard is the small OLED screen near the Apple logo. That works with the QMK firmware to display status and configuration information.
The result is a keyboard with all of the benefits of modern technology combined with the style of vintage hardware.