The two most useful and versatile devices in a maker’s arsenal are a Raspberry Pi single-board computer (SBC) and an Arduino development board. Every model of Raspberry Pi is a complete computer in a form factor small enough to fit into just about any project, and every model of Arduino contains all of the hardware you need to utilize a microcontroller to work with low-level hardware components. It’s only natural for the two to be combined, and, with that in mind, Hartmut Grawe designed an all-in-one Raspberry Pi handheld specifically for microcontroller work.
Grawe's project was based heavily on Anthony DiGirolamo’s fantastic HyperPixel Raspberry Pi handheld featuring his Teensy Thumb Keyboard design. That design was intended to fill the same role as the now defunct Next Thing Co. Pocket C.H.I.P. handheld computer, and Grawe has fleshed out that concept by adding a few components that facilitate the development of microcontroller-based projects. Those components are an Adafruit Feather M0 board with the RFM69HCW radio module, an OLED screen for debugging, and a small breadboard for connecting the hardware that you’re working with. All of that fits into a package that fits easily in your hands, so you can work on your projects wherever you are.
Aside from those additions, this is mostly a straightforward rendition of Anthony’s design. That means you can use either a Raspberry Pi 4 or a 3B+. The built-in keyboard connects to the Raspberry Pi via a Teensy 3.2 board. The screen is a HyperPixel 4.0” TFT high-res display that can be optionally equipped with capacitive multi-touch. Grawe is powering the device from a battery pack via a StromPi power board. All of those components fit tidily inside a 3D-printable enclosure (Grawe recommends avoiding ABS due to the precision required). If you’ve been looking for a way to work on your microcontroller projects when you’re out and about, this all-in-one handheld computer is worth your consideration.