Andy Geppert's Raspberry Pi RP2040-Powered SAO Demo Controller Delivers Easier Badge Hacking

Designed to sit between a badge and an SAO, or to take the place of a badge, the SAO Demo Controller eases development and showcasing.

Gareth Halfacree
2 months ago β€’ Badges / HW101

Mechatronics engineer and maker Andy Geppert is no stranger to badge life, having designed a number of Simple Add-Ons [SAOs] β€” but his latest creation is designed to make life easier when it comes time to testing an demonstrating them: the SAO Demo Controller.

"There are two intermediate needs to avoid having a dark and motionless SAO on your badge," Geppert explains of the problem he set out to solve. "A) The need to demonstrate what our SAOs are capable of. B) The option to use the SAO without creating firmware on every badge you want to use the SAO with. To meet those two intermediate needs, this project was conceived."

The SAO Demo Controller is, effectively, a man-in-the-middle gadget with one SAO plug and one SAO socket β€” allowing it to sit between any badge and any add-on following the Simple Add-On standard. The controller itself has an on-board Raspberry Pi RP2040 microcontroller, which can host work-in-progress firmware and demo applications to show off SAO capabilities β€” without having to program the badge itself, and even without having to use a badge at all.

"Additional features of the SAO Demo Controller are: Dual SAO plug mounting option. Option to connect the SAO plug header vertically (edge) or horizontally," Geppert writes. "Right-angle pass-through adapter. Use it the bare board as a right angle adapter for your SAO, with pass-through functionality. Connect I2C accessories. Add one or two QWIIC/STEMMA QT sockets to leverage those broad I2C ecosystems. Experiment with the RP2040-Zero as an accessory to your badge via I2C or UART."

The project is documented on Hackaday.io; at the time of writing, Geppert had not yet released design files for the board.

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