Front Door Camera (Slave Unit)

Hardware: ESP32-CAM (AI-Thinker Model) with OV2640 Sensor.

Role in Project

This device acts as a "dumb" sensor for the main Doorbell Controller (ESP32-S3). It handles the specific timing requirements of the camera sensor to ensure clear images without "green tint" or stale buffers.

Interface

• Protocol: UART Serial (TX/RX)
• Baud Rate: 115200
• Wiring:
  • 5V/GND: Shared with Master
  • U0R (RX): Connected to Master TX (Pin 17)
  • U0T (TX): Connected to Master RX (Pin 18)

Logic Flow

1. Waits for character 'S' on Serial.
2. Double-Tap Capture: Takes one photo and discards it (flushes sensor buffer), then immediately takes a second photo.
3. Transmission:
   • Sends Image Size (4 Bytes).
   • Sends raw JPEG Data.

Flashing

• Board: AI Thinker ESP32-CAM
• Mode: DIO, 40MHz