ClockworkPi DevTerm Thoughts

2023-08-01

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At the end of March, I received a ClockworkPi DevTerm UMPC. I didn't have much of a chance to play with it in April or May, but since about the end of June, I've been using it as my primary mobile PC. After about five weeks of consistent use, I have a number of thoughts about the platform.

My model is the DevTerm Kit RPI-CM4. The kit itself is a set of computer components: screen, keyboard with integrated trackball, main board, and peripherals, along with a shell. The kit is very simple to build: no soldering or screws are required. Swapping and upgrading components is extremely easy. Best of all, the hardware is open-source, and schematics and 3D-printing files are available on ClockworkPi's GitHub page. Assembly took only a few minutes.

A Raspberry Pi Compute Module 4 is not included inside the kit itself, but Clockwork does include one in the purchase. Two 18650 lithium-ion batteries are required for mobile use but are not included at all. Fortunately, I had a few left over from a much earlier project.

The device's external connections include three USB-A ports, one type-C power port, one micro HDMI port, one 3.5 mm TRS audio port, and an expansion port used by a thermal printer. Apparently the power port can also charge the batteries, but for some reason this doesn't work for me. Included with the kit is a thermal paper spool that can be plugged into and removed from the DevTerm at will. The fully-assembled kit measures approximately 210 mm x 160 mm x 32 mm without the paper spool, or 210 mm x 215 mm x 32 mm with the spool. This is small enough to fit comfortably into a cross-body bag but too large to fit into a pocket. With my 2500 mAh batteries and a spool fully loaded with paper, the device weighs around 715 g--not the lightest UMPC, but certainly not bad for a mobile printer!

ClockworkPi included an SD card in the kit with Raspberry Pi OS, a Debain derivative, pre-installed. This was quite convenient, but the included card was only 32 GB in size, which I felt was too small for my purposes. I flashed a 128 GB card with the image of the included card, then after initial setup I expanded the root volume to use the rest of the card's space.

The CM4 is mainlined into the Linux kernel, which opens the device up to all the software available for Debian on ARM. I absolutely love this: my other UMPC is a PlanetComputers Gemini PDA, which was never mainlined and whose build of Debian is permanently stuck on Debian 9 "Stretch" and a modified 3.18 kernel. I can install and upgrade software freely with the DevTerm, which immediately makes it much more viable as a daily driver UMPC.

The screen of the DevTerm is quite odd: a 6.86-inch 8:3 ultrawide with a resolution of 1280x480. ClockworkPi calls this resolution "deal retro" and is equivalent to side-by-side 640x480 VGA. This is fine in theory, but in practice, most modern software assumes a minimum resolution of 800x600, or even 1280x720. On several occasions, dialog boxes that cannot be resized continue off the bottom of the screen. There are some workarounds available on ClockworkPi's forum, but out of the box, this resolution is simply too low without some kind of screen scrolling or modified desktop interface (or without using CLI exclusively).

The keyboard of the DevTerm is also rather difficult to type on. It packs a lot of functionality into a tiny space--there are 67 keys, 3 mouse clickers and 8 gaming buttons--but the smallest keys are only about 12 mm wide, one third smaller than the 18 mm keys I have on my desktop keyboard. I don't have the most slender fingers, ad as a result I find that I have lots of typos whenever I write on the device.

Overall, however, I absolutely love the DevTerm. While it doesn't have the sleek mini-laptop form factor of the Gemini PDA, it is far more powerful, has better support, is repairable and upgradeable, and is easier to use. If you are a fan of UMPCs--and have slim fingers--I recommend this device.

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[Last updated: 2023-08-01]