picowallet: A stablecoin hardware wallet from three Amazon parts, no soldering.

picowallet is a hardware wallet for the USDS stablecoin, built from three off-the-shelf parts costing about $35 in total with no soldering required. A Raspberry Pi Pico 2 W, a Waveshare LCD board and an Adafruit ATECC608 secure-element breakout make up the device, and the signing key never leaves the chip. The vault contract, ChipAccount, moves USDS only with a valid P-256 signature from the current hardware key. One Dollar Audit engagement 850 reviewed the deployment on 2026-09-06 and reported 3 high, 3 medium, 4 low and 3 informational findings, and the article describes the project as a PoC, not an audit guarantee.