Balazs' HaLiTerm Mini Is an Ultra-Compact All-in-One Powered by a NanoPi NEO Air and RP2040

Pseudonymous maker and self-described "perpetually hobby-hopping person" "Balazs" has taken an earlier project, the HaLiTerm handheld Linux terminal, and considerably shrunk it down to create the pocket-friendly HaLiTerm mini — with sacrificing functionality.

"This is a tiny serial terminal with a memory in pixel display and a built-in NanoPi NEO Air," Balazs explains of the svelte gadget. "This device is a serial terminal based on the [Raspberry Pi] RP2040 microcontroller. The NanoPi NEO Air is connected over UART to the RP2040. The display is a Sharp memory-in-pixel LCD display connected over SPI."

The concept behind the HaLiTerm mini goes back to Balazs earlier HaLiTerm project, which, like its baby brother, houses a NanoPi NEO Air single-board computer alongside a Raspberry Pi RP2040-based Raspberry Pi Pico that acts as a serial terminal. Where the original model used a 5" 800×480 TFT panel and a keyboard made up of 71 full-size key switches, though, the HaLiTerm Mini is a lot smaller.

While mimicking its bigger sibling's design, the HaLiTerm mini swaps the 5" display for a 2.7" version with a 400×240 resolution. A 10,000mAh battery has been shrunk down to a 1,100mAh version, but — interestingly — the keyboard remains intact, albeit at a much smaller scale. "The keyboard buttons are made of two 3d-printed parts and are held in place by slots in the front PCB," Balazs explains. "It required a lot of tweaking and experimenting to get usable results."

While a fraction of the size of its predecessor, the HaLiTerm mini is fully-functional: there's the same NanoPi NEO Air single-board computer inside, and the same RP2040 microcontroller acting as a serial terminal. The smaller screen does mean a reduction in the amount of information displayed, though careful selection of a 5×10 pixel-perfect bitmap font means it's possible to squeeze 24 80-column lines on there and still have it be readable.

Design files and source code for the HaLiTerm mini have been published on Hackaday.io under a public domain license; a separate project page covers the earlier full-size HaLiTerm.