I use a general‑purpose ESP32 board (ESP‑WROOM‑32) with a dual‑core 240 MHz processor, built‑in WiFi and Bluetooth, and plenty of free GPIO pins as the sensor node.
For each ultrasonic sensor, I send a 10‑microsecond pulse on the Trig pin.
Requesting http://<ip>/distance returns JSON with null for no echo.
The camera module includes an OV2640 camera, 4 MB of extra memory (PSRAM).
It serves a control page at http://<ip>/, and the live MJPEG video stream is at http://<ip>:81/stream.
I decided to keep sensing and streaming on separate ESP32 boards to avoid pin contention, limit memory pressure, and simplify wiring; the sensor node uses a 10 µs trigger and a 60–120 ms inter‑sensor delay, while the camera node streams QVGA JPEG frames on a dedicated port.