For Rudex we developed a purpose-built device that verifies identity (Face-ID) and sobriety (breathalyzer) in a single pass before every shift. The system is architecturally split into two services — an edge gateway on a Raspberry Pi that communicates with the physical breathalyzer over a serial link and runs even without internet, plus a central dashboard application where HR and shift supervisors see who passed, who didn't, and what happened. All controlled, all connected.
The story
Software and hardware shouldn't be a hard boundary — the serial link to the device and the central record, all developed by us.
Worth noting
Pre-shift alcohol checks at the industrial site were slow, done by people, and there was no systemic link to the worker's identity. Identity verification and the test itself were separate processes, so the record of who exactly was tested could be disputed. In manufacturing industries, where an intoxicated worker on the production line isn't just an HR problem. Plus two separate machines at the entrance mean two lines, double the long wait for a shift of 100+ people.
We developed the system as two interconnected services. The edge gateway runs on a Raspberry Pi with the device at the entrance and communicates with the physical breathalyzer over a serial link — the moment a worker approaches, the gateway runs Face-ID recognition, then sends a command to the breathalyzer, reads the result, and locally writes the event to its database. If the internet has gone down, the device still works: later it syncs all accumulated events with the central system as soon as the network is back. The central dashboard application has everything — HR sees attendance by shifts, shift supervisors have a scheduling calendar, and photos from Face-ID checks are kept in storage as evidence alongside every record. The system doesn't allow entry if either of the two checks fails, and every outcome leaves an audit trail.
Modules & surfaces
The hardware side requires different discipline from a web app — the device MUST work every shift, every day, even when the network goes down. So we designed the gateway as offline-first from the start, with its own database and later sync. Authentication speed was also critical: a 90-second entry per worker means a 30-minute queue at the gate when there are 100+ people. Every decision — the Face-ID model, the serial communication, even the choice of the Pi as the platform — had a clear reason tied to the actual conditions on site.
A pre-shift check that used to take minutes now takes seconds. Shifts begin only if both checks pass, with photographic evidence on every record. The network can fail — the device keeps working and syncs later. Rudex now has an unimpeachable audit trail for every shift, connected to the HR system and the company's full operational system.