IoT Toll Fingerprint Authentication

I’m building a three-stage authentication flow for an automated toll plaza and want the core logic to run on an ESP8266/ESP32. The critical layer is biometric security, so fingerprint scanning will be the user’s decisive checkpoint before the barrier lifts.

System outline
• Stage 1 – the node wakes when a vehicle is detected and prepares the sensor stack.
• Stage 2 – the traveller places a finger on the scanner; the board must capture, match locally, then encrypt the result.
• Stage 3 – the ESP transmits the signed approval to my cloud endpoint; only a positive response prompts the relay that opens the gate.

What I need from you
1. Firmware (Arduino IDE or ESP-IDF) that handles sensor drivers, match-on-device logic, and secure HTTPS/MQTT messaging.
2. A concise wiring diagram and BOM showing the fingerprint module, ESP, relay, power regulation, and any level-shifters.
3. A short setup guide so I can flash, enrol prints, and test end-to-end on my bench.

Acceptance criteria
• First print-to-decision time under 2 s.
• TLS-encrypted traffic validated with a self-signed certificate I’ll supply.
• Clean, well-commented code that compiles without warnings.

If you have prior work with well-known fingerprint modules (R503, GT-521), let me know; otherwise I’m open to your recommended part as long as it fits the ESP’s UART/SPI constraints.