Jonathan Broadwell Unveils New Serial Wombat 8B Smart Expansion Boards

Maker Jonathan Broadwell is back on the crowdfunding circuit with four new additions to his Serial Wombat 8B development board expansion platform: a high-side driver, low-side driver, infrared transceiver, and an I2C multiplexer with input/output expansion.

"The Serial Wombat 8B is [a] microcontroller preprogrammed with firmware that turns it into an I2C peripheral that provides smart I/O [Input/Output] expansion to solve common interfacing problems — ADC [Analog to Digital Conversion], PWM [Pulse-Width Modulation], servo, GPIO [General-Purpose Input/Output], rotary encoder reading, H-bridge interfacing, and more," Broadwell explains. "As a separate microcontroller it can offload annoying or interrupt intensive I/O tasks from your main board. It's open-source firmware running on an inexpensive [WCH Electronics] CH32V003 microcontroller. The hardware designs are open-source hardware. You don't program a Serial Wombat board. You command it in real time like any other I2C device using available Arduino, Python/MicroPython, or C# libraries."

The Serial Wombat 8B itself launched via crowdfunding back in April last year, as a successor to the original Serial Wombat range. Broadwell's new boards are designed to expand the Serial Wombat 8B's capabilities in four task-specific directions — starting with the high-side driver board, which uses Texas Instruments TPS4H160-Q1 high-side switches to deliver support for eight loads at up to 2A each with pulse-width modulation (PWM) control and current feedback with fault detection over I2C.

The low-side driver board, meanwhile, offers eight PWM-capable outputs at up to 4A per channel with a limit of 8A per board plus 24V-capable inputs. An infrared transceiver board — dubbed the "RemCon board" by Broadwell for its likely application in remote control projects — adds both transmission and reception of IR signals, with encoding happening in the on-board Serial Wombat 8B controller to offload from the host microcontroller. Its initial release will support the NEC protocol, its creator says, while "other protocols may be added in the future." Finally, the multiplexer board offers four I2C sub-busses for connecting multiple devices sharing the same I2C address to a single host.

All boards include the WCH CH32V003 microcontroller with Serial Wombat 8B firmware on-board, and are being made under open-hardware licenses with permissive MIT-licensed firmware. "Every PCB has either a URL or QR code that takes you specifically to documentation for that board printed directly on the silkscreen," Broadwell notes of the boards' ease-of-use, along with the promise of over 130 pages of documentation covering the whole Serial Wombat ecosystem. "I even registered an additional domain (https://serwom.com) to facilitate putting a direct URL on really small boards."

Broadwell's new crowdfunding campaign is now live on Kickstarter, with pricing starting at $49 for all four new boards or $99 for a full set of all 11 Serial Wombat 8B boards; all hardware is expected to ship in June this year, but is only available to backers in the United States.