ESP32 Project for detecting a Light change from Red to Green

Purpose

• Check out the video of it in action
• I don't like having to watch a red light until it turns green, so I made the green light alert. As of now, it sends me an alert over bluetooth when the light turns green. It's using Edge Impulse.

#Hardware needed ( so far )

• esp32s3 sense
• A basic on/off switch
• A liPo battery like this
• An android phone (for now)

This repo contains:

• esp32_serial_camera_viewer: native macOS C++ viewer for JPEG frames over serial
• esp32_camera_viewer: native macOS C++ viewer for HTTP MJPEG streams
• serial_saver: native macOS C++ serial packet receiver that saves images into trafficimages/
• arduino/esp32_serial_camera_sender: Arduino sketch that either sends camera JPEG frames over serial or runs on-device traffic-light detection

Desktop build

Requirements:

• CMake
• OpenCV

Build:

cmake -S . -B build
cmake --build build

Arduino project

Open this sketch in Arduino IDE:

arduino/esp32_serial_camera_sender/esp32_serial_camera_sender.ino

Default target board profile is Seeed Studio XIAO ESP32S3 Sense. If your hardware is different, edit:

arduino/esp32_serial_camera_sender/camera_pins.h

Key camera and serial settings live in:

arduino/esp32_serial_camera_sender/config.h

If you are using an OV5640 autofocus module, also install the Arduino library OV5640 Auto Focus for ESP32 Camera. The sketch enables autofocus automatically when that library is available.

Traffic-light detection currently runs entirely on the ESP32-S3 using RGB565 frames and heuristic color/blob logic. It reports the red lamp location plus an inferred green-lamp ROI every 500 ms.

Optional debug MJPEG streaming is available over Wi-Fi. Enable it in config.h by setting:

• kEnableDebugMjpegStream = true
• kWifiSsid
• kWifiPassword

Debug endpoints:

• /stream for MJPEG
• /capture for a single JPEG
• /status for JSON detector status

This is intended for debugging only and can be disabled cleanly without affecting the main detector flow.

When the ESP32 finds a red light, it also sends two packetized JPEG images over serial:

• the full frame where the red light was found
• the inferred green-light ROI

Build and run the image saver:

cmake -S . -B build
cmake --build build --target serial_saver
./build/serial_saver --device /dev/cu.usbmodem1101

Saved images are written to:

trafficimages/

Serial run

Find the serial device:

ls /dev/cu.*

Run the macOS viewer:

./build/esp32_serial_camera_viewer --device /dev/cu.usbmodem1101 --baud 921600

Press q to quit.

Do not open Serial Monitor at the same time.

If camera init fails on your ESP32-S3 board, the usual cause is a mismatched camera pin map rather than a desktop-side issue.