# 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