Ahmsville Labs' Pico Dev M3 Turns a Raspberry Pi RP2040 Into a Feature-Packed Rotary Encoder Knob

Featuring a 3D-printed smooth-turning housing and a resolution up to 36,000 steps per revolution, this dev board will turn heads.

Gareth Halfacree
10 days agoHW101 / 3D Printing

Nigeria-based Ahmsville Labs has launched an interesting development board, which pairs a Raspberry Pi RP2040 dual-core microcontroller with a high-resolution magnetic rotary encoder on a round PCB — designed for insertion into a 3D-printed knob housing.

"The Pico Dev M3 is a development board based on Raspberry Pi's RP2040 microcontroller chip," the company explains of its design. "The board is also a high-resolution magnetic rotary encoder when paired with a few 3D-printed parts, which makes this the perfect board for applications and projects that can benefit from having a rotary encoder — a good example is making macro pads, and other similar secondary controllers."

The circular PCB is built around the RP2040, a dual-core Arm Cortex-M0+ clocked at a stock 133MHz and with 264kB of on-chip static RAM (SRAM). To this Ahmsville Labs has added 2MB of QSPI external flash while bringing out 19 general-purpose input/output (GPIO) pins including 16 pulse-width modulation (PWM) channels, two analog inputs, two UART, two I2C, and two SPI buses.

The on-board rotary encoder offers a base 36-step resolution, extendable to 36,000 steps per revolution. Much of the circumference of the board, meanwhile, is festooned with a total of 18 individually-addressable LEDs — leaving room only for a USB Type-C connector to one side for data and power. The 3D-printable housing, meanwhile, turns the board into a rotary knob — albeit one that's entirely stand-alone.

Ahmsville Labs is selling the Pico Dev M3 on Tindie at $21.20 for the board alone or $41.50 with the rotary encoder hardware added. The company has pledged to release sample source code and the 3D print files for the encoder housing on the project's GitHub repository, but at the time of writing only a placeholder file was published.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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