ALPR / PRIVACY

ALPR PRIVACY / BUILD & USE

Wiring reference

Prototype signal assignments, with the boundaries of the current design made explicit.

Prototype signal flowGPS SDA and SCL connect to GPIO8 and 9. A maintenance button connects GPIO10 to ground. GPIO5 controls a compatible driver and indicator. The board SD interface uses its defined SD MMC pins.GNSS receiverI²C • 3.3 V logicESP32-S3 prototypeGPIO8 — SDAGPIO9 — SCLGPIO10 — buttonGPIO5 — outputSD_MMC pin map in table belowMaintenance buttonMomentary switch to GNDCompatible output driverRelay + LED interfacemicroSD storageBoard-specific SD wiringUse matched power and grounds. Film supply / vehicle wiring not shown.
Functional signal reference derived from the sketch; supply and protection circuits are intentionally not specified here.
SignalPrototype assignmentConnection / qualification
GNSS SDAGPIO83.3 V-compatible I²C SDA.
GNSS SCLGPIO93.3 V-compatible I²C SCL.
Maintenance buttonGPIO10INPUT_PULLUP; momentary switch to GND.
OutputGPIO5Active-high control signal to a compatible driver; LED needs a suitable current-limiting circuit.
SD CLK / CMDGPIO38 / GPIO34Matches the current sketch’s SD_MMC setup; verify board wiring.
SD D0 / D1GPIO39 / GPIO40Board-specific SD bus.
SD D2 / D3GPIO47 / GPIO33Board-specific SD bus.

Before the final schematic

  1. Confirm the exact ESP32 board part number, revision and pin availability.
  2. Select a 3.3 V logic-compatible relay interface and document its supply, input behavior and load ratings.
  3. Specify the indicator LED resistor or driver.
  4. Confirm reverse-mode film behavior and its matching supply with the film manufacturer.
  5. Document fusing, reverse-polarity and transient protection, enclosure, grounding and connectors.

Continue to the bench assembly guide →