An ESP32-based presence detection system that automatically turns on/off fans and lights using a radar sensor and relay module. The system detects human presence and movement, providing hands-free automation for your home or office.

• Presence Detection: Uses radar sensor for accurate human presence detection
• Automatic Control: Turns fan/light on when presence is detected, off when no one is present
• Real-time Monitoring: Provides detailed target information including position, speed, and distance
• UART Communication: High-speed communication at 256kbps for reliable data transfer
• GPIO Control: Simple relay control via ESP32 GPIO pins
• Non-contact Detection: Works through walls, clothing, and in various lighting conditions

• ESP32 development board
• Radar sensor module (compatible with the protocol used in this code)
• Relay module (5V or 3.3V compatible)
• Fan and/or light fixtures
• Jumper wires
• Power supply (12V for fan, appropriate voltage for lights)
• Breadboard or PCB for connections

• ESP-IDF framework
• FreeRTOS (included with ESP-IDF)
• Standard ESP32 libraries

git clone <repository-url>
cd radar-sensor-control

# Set up ESP-IDF environment
. $HOME/esp/esp-idf/export.sh

# Configure the project
idf.py menuconfig

# Build the project
idf.py build

# Flash to ESP32
idf.py -p /dev/ttyUSB0 flash monitor

• main.c - Main application logic and initialization
• radar_sensor.h - Header file with radar sensor definitions
• radar_sensor.c - Radar sensor driver implementation (provided in paste.txt)

• radar_sensor_init() - Initialize radar sensor structure and pins
• radar_sensor_begin() - Configure UART communication
• radar_sensor_update() - Parse incoming radar data
• radar_sensor_parse_data() - Extract target information from raw data
• radar_sensor_get_target() - Get current target data
• radar_sensor_deinit() - Cleanup resources

• Initialize radar sensor on UART1
• Continuously monitor for presence
• Control relay based on detection status
• Log target information for debugging

• Baud Rate: 256,000 bps
• Data Bits: 8
• Parity: None
• Stop Bits: 1
• Flow Control: None

The radar sensor uses a specific frame format:

• Header: 0xAA 0xFF 0x03 0x00
• Data Frame: 24 bytes of target information
• Tail: 0x55 0xCC

• Position: X, Y coordinates in millimeters
• Speed: Movement speed in cm/s
• Distance: Calculated distance from sensor
• Angle: Direction of target relative to sensor

1. Power On: Connect power to ESP32 and radar sensor
2. Automatic Detection: The system continuously monitors for presence
3. Fan/Light Control:
   • Presence Detected: Relay activates (GPIO 1 HIGH), turning on fan/light
   • No Presence: Relay deactivates (GPIO 1 LOW), turning off fan/light
4. Monitor Logs: Use serial monitor to view detection status and target data

I (1234) RADAR_WATCH: Radar sensor initialized successfully
I (1456) RADAR_WATCH: Target detected - X: 850.00 mm, Y: 1200.00 mm, Speed: 15.50 cm/s, Distance: 1478.32 mm, Angle: 35.23°
I (1789) RADAR_WATCH: No target detected

Modify the detection logic in radar_sensor_parse_data() to change sensitivity thresholds.

Adjust the delay in the main loop:

vTaskDelay(pdMS_TO_TICKS(100)); // 100ms delay

Add more GPIO pins for controlling multiple devices:

gpio_set_direction(GPIO_NUM_2, GPIO_MODE_OUTPUT); // Second relay
gpio_set_direction(GPIO_NUM_3, GPIO_MODE_OUTPUT); // Third relay

1. No Radar Data Received

   • Check UART pin connections (RX/TX may be swapped)
   • Verify baud rate setting (256000)
   • Ensure radar sensor is powered correctly

2. Relay Not Switching

   • Check relay module power supply
   • Verify GPIO pin connection
   • Test relay module independently

3. False Detections

   • Adjust radar sensor position
   • Modify detection thresholds in code
   • Check for electromagnetic interference

4. Compilation Errors

   • Ensure all header files are included
   • Check ESP-IDF version compatibility
   • Verify component configuration

• Use ESP_LOGI() statements for debugging
• Monitor serial output for radar data
• Test relay independently with simple GPIO toggle
• Verify UART communication with oscilloscope if available

• Ensure proper electrical isolation between low-voltage control and high-voltage loads
• Use appropriate fuses and circuit breakers
• Follow local electrical codes and regulations
• Consider using optically isolated relays for better safety
• Test thoroughly before permanent installation

• Add web interface for remote monitoring
• Implement presence timeout delays
• Add motion-based sensitivity adjustment
• Include multiple detection zones
• Add smartphone app integration
• Implement energy usage monitoring

This project is licensed under the MIT License - see the LICENSE file for details.

For issues and questions:

• Check the troubleshooting section
• Review ESP-IDF documentation
• Create an issue in the project repository