Protective Stop
An open source safety stop for robots and industrial machines, with its assurance case written in public alongside the device.
A PoE- or USB-powered ESP32-S3 remote sends operator intent to the machine ten times a second over an encrypted link. When the messages stop, because the operator let go, the link dropped, or the remote lost power, the machine brings itself to a controlled halt rather than losing power where it stands. The project targets SIL 3 under IEC 61508 and PL e under ISO 13849. The firmware runs lockstep across both cores, the protocol library sits on its own certification track behind a MISRA checker, and a chaos proxy in the test suite mangles the network on purpose. Software is Apache-2.0, hardware CERN-OHL-P-2.0, documentation CC-BY-4.0, and the open items are recorded as open items.
