UPDATE (4/27/2021): Peter "Bobricius" Misenko has now opened up sales of bare prototype PICOmputer PCBs for anyone eager to try building their own, offering a bundle with back-panel and front plate for $10 on Tindie. No components are included, however, and the current board design does not yet include Ethernet or microSD support.
Original article continues below.
Misenko's design for a handheld, self-contained portable computer based on the Raspberry Pi Pico microcontroller development board has reached near-full functionality — two months after the design was first teased.
Launched earlier this year as the first, but far from the last, outing for Raspberry Pi's in-house RP2040 microcontroller chip, the Raspberry Pi Pico has proven popular — and Misenko was among the first to pledge support for the part with a handheld computer design, acting as a precursor for a MicroPython-based implementation of his Armachat off-grid wireless communication platform.
Now, Misenko's prototype is ready — and it's a pocket-size powerhouse of basic computing, capable of running MicroPython, CircuitPython, Arduino, and straight C/C++ programs. "There is nothing [else inside]," Misenko shows in a short video demonstration, "just Raspberry [Pi] Pico."
The Raspberry Pi Pico is used to drive a range of accessories, starting with a compact microswitch keyboard based on the design used in Misenko's Armachat family. A small form-factor IPS display, offering 240x240 resolution, is found at the top-right, while on the rear there's a piezoelectric buzzer and a mounting point for an optional LoRa radio module — currently untested, Misenko admits.
An interesting design twist sees the system, dubbed the PICOmputer, receive two USB ports, one above the other: The micro-USB port on the Raspberry Pi Pico is used for programming, while a second USB Type-C cable can be used to power the device. The sandwich-style board design takes advantage of the castellated header on the Raspberry Pi Pico to solder it as a surface-mount module, and includes spare GPIO header pins broken out to the top of the board.
More details are available in the description of Misenko's demo video, where he has also teased plans for a revised design which will add a micro-SD card and headers for an optional Ethernet networking module. While Misenko has said the board will be "cheap," no price has yet been disclosed.