The YARH.IO M4 Is a Raspberry Pi-Powered Handheld You Can — Finally — Build Yourself

Pseudonymous maker "snc" has released 3D print files and instructions for building your own YARH.IO M4 — a slab-format handheld cyberdeck powered by a Raspberry Pi 4 Model B and featuring a neat desk stand, active cooling, and integrated charging capabilities.

"Two years ago I posted the [YARH.IO] M4 as a WIP [Work-In-Progress]," snc writes of the project, the third generation in a family of do-it-yourself cyberdeck builds. "It took me a while, but I finally put everything together and published the full build documentation, parts list, assembly guide, and STL files on yarh.io. The M4 is a Raspberry Pi 4B handheld running i3 window manager with an adjustable 3D-printed stand. [The] STL files cover both [Raspberry] Pi 4 and Pi 3 variants."

Known at the time of its launch as the YARH.IO Micro 4, the M4 is a compact handheld whose size is largely dictated by the Raspberry Pi 4 Model B single-board computer which powers it — a device that lags behind the latest Raspberry Pi 5 in terms of performance but which can be purchased for less, or found languishing in a spares drawer waiting for a new purpose. A full-color 4.3" touchscreen display panel sits above an off-the-shelf Bluetooth keyboard for handheld use, while full access to the Raspberry Pi 4's USB ports means it's easy to connect an external keyboard when using the optional desktop stand.

Beneath the Raspberry Pi, which is kept cool via vents in the back of the 3D-printed case feeding fresh air to an active heatsink and fan add-on, is a step-up voltage regulator for a lithium battery — with an onsemi LC709203F fuel-gauge chip feeding its status back to the operating system via a custom monitoring daemon. "The i3status bar picks up this data and displays battery level right alongside CPU usage and network status," snc explains. "You always know exactly how much runtime you have left without opening a separate application."

While the YARH.IO M4 was first unveiled two years ago, it hasn't been possible to build your own — until now: snc has released not only a full parts list, plus the source code for the battery daemon that was released at the time of the gadget's original unveiling, but STL files for 3D printing both the case and the desktop stand. "[It's] a great way to give new life to an old Raspberry Pi 3 or 3A+ that's been sitting in a drawer," the maker notes. "Drop it in, wire it up, and you've got a fully functional handheld computer. It won't be fast — but it will be yours, it will work, and it's a genuinely fun build. Sometimes the best project is one that turns forgotten hardware into something you actually want to pick up and use."

More details are available on YARH.IO, while the battery monitor source code is available on GitHub under the permissive BSD two-clause license. snc also sells pre-assembled M4s on the YARH.IO shop at $479, while additional discussion can be found in the maker's Reddit post.