A developer has created Park07/amradio, a formally verified FPGA-based AM radio broadcast system for emergency alerts in unmanned tunnels. The system uses a Red Pitaya FPGA to transmit 12 simultaneous AM carrier frequencies between 505-1605 kHz, with pre-recorded audio messages and dynamic power scaling. The Rust + JavaScript architecture features an event-driven pub/sub model and stateless UI that treats the hardware as the source of truth.

What sets this project apart is its formal verification of the hardware watchdog timer using bounded model checking and k-induction. The verification proves 14 safety properties across all possible states and inputs, including guarantees that the watchdog trigger only fires after a 5-second timeout and that warnings occur before triggering. Six cover scenarios were also validated, ensuring the system behaves correctly during the complete warning-to-trigger lifecycle. The formal proof uses reduced clock frequencies for tractability but applies to the full production implementation.

The system includes a fail-safe hardware watchdog that kills RF output if the GUI heartbeat stops for 5 seconds, requiring manual operator reset to restore transmission. This makes it particularly suitable for critical infrastructure where unmanned operation and guaranteed fail-safe behavior are essential requirements.