A single-board computer (SBC), particularly a model like the Raspberry Pi Zero W, is perfect for mobile computing. But that portability kind of goes out the window if you have to lug around a full-size keyboard to use it. There are plenty of mini Bluetooth keyboards on the market, but they’re meant to be standalone devices. Anthony DiGirolamo’s Teensy Thumb Keyboard, on the other hand, is a great way to build a keyboard right into your projects.
As the name suggests, this keyboard is meant to be used with a Teensy — specifically the Teensy 3.2. But, it will also work with boards that have a similar footprint, including: the Teensy-LC, Butterfly STM32L433, and Dragonfly STM32L476/96. To use it with your Raspberry Pi, or any other computer, you just setup the Teensy to act as a USB HID (Human Interface Device) so that it shows up like any other USB keyboard.
The keyboard itself has 60 tactile push buttons, which include a full QWERTY layout, a num pad, and various function keys. It also has breakout pins for I2C, SPI, and two GPIOs. DiGirolamo has released all of the relevant files on GitHub, so you an build your own Teensy Thumb Keyboard, and that even includes a 3D-printable case you can use to build a Raspberry Pi 3 B+ handheld. DiGirolamo is also hoping to sell kits on Tindie soon, so you won’t have to get PCBs made yourself.