DFRobot - mmWave - C4001 24GHz Human Presence Detection Sensor for Arduino & ESPHome (25 Meters, UART)

Upgrade smart automation with the C4001 24GHz mmWave Sensor. Unlike traditional PIR sensors that only detect large movements and fail when occupants remain still, this sensor utilizes advanced FMCW (Frequency-Modulated Continuous Wave) technology to detect micro-motions such as human breathing.

Engineered for long-range and high-precision applications, it accurately detects human presence up to 16 meters and motion up to 25 meters, making it ideal for large living spaces, long corridors, and comprehensive security monitoring.

Why Choose the C4001?

• True Presence Detection: Accurately senses people who are sitting, lying down, or even sleeping.
• High Environmental Immunity: Unaffected by temperature, humidity, dust, light, or noise.
• Long-Range Sensing: Covers areas up to 25m, significantly outperforming standard 9m or 5m radars.
• Effortless Integration: Designed for compatibility with Arduino, ESPHome, Home Assistant, and other popular DIY platforms.

Detection Range of millimeter-wave human body sensor

mmWave vs. PIR: Choosing for Occupancy Detection

PIR sensors are commonly used for motion-triggered applications. The C4001 also detects small movements associated with human presence, making it useful for occupancy projects where people may remain relatively still.

Simplified & Straightforward Integration

The C4001 24GHz mmWave sensor is designed for easy implementation. With a simple wiring setup, the C4001 can be operational within a project in a short amount of time.

Wiring diagram of the C4001 millimeter-wave human body sensor and Arduino Uno

How It Works: The FMCW Advantage

The C4001's precision is derived from its Frequency-Modulated Continuous Wave (FMCW) radar technology. It continuously emits a signal and analyzes frequency shifts in the return wave. This method allows it to determine an object's distance and, through the Doppler effect, detect microscopic movements—such as breathing—which is the key to its unparalleled static presence detection capability.

Flexible Installation Options

For optimal performance, the installation method should be chosen to suit the intended application. Top-down installation is ideal for room-wide coverage, while tilted or horizontal installation is better for directional sensing in specific zones.

Top Installation Diagram of millimeter-wave human body sensor

Bottom Installation of millimeter-wave human body sensor

Horizontal Installation of millimeter-wave human body sensor

C4001 24GHz radar for long-range indoor sensing: up to 16m for human presence and up to 25m for motion detection. Distance measurement is specified from 1.2m to 25m. Detection results depend on installation and the target; these ranges describe different sensing tasks, not one interchangeable maximum.

• Human detection: Detection range up to 16 meters and motion detection range up to 25 meters.
• Distance detection: Range from 1.2 meters to 25 meters.
• Velocity detection: Range from 0.1 meters per second to 10 meters per second.
• Strong anti-interference capability, unaffected by snow, haze, temperature, humidity, dust, light, noise, etc.
• High and low-level output control through I/O ports.
• Input and output control via serial port.
• Small size, easy to integrate.

• Occupancy-Based Bathroom Automatio: Ensures lights and exhaust fans remain active as long as the space is occupied, then shut off automatically when vacant. This provides a hands-free, convenient, and energy-efficient solution.
• Presence-Triggered Monitoring Projects: Unlike motion detectors prone to false alarms from environmental factors, the C4001 detects actual human presence. This allows for security systems that provide more meaningful alerts when individuals linger in a protected area.
• Occupancy-Based Lighting and HVAC Control: In offices or living spaces, the C4001 24GHz mmWave sensor enables precise occupancy-based control of HVAC, air purifiers, and lighting systems.

• Operating Voltage: 3.3V / 5V
• Operating Frequency: 24GHz
• Modulation Mode: FMCW
• Maximum Motion Detection Range: 25m
• Human Presence Detection Range: 16m
• Distance Measurement Range: 1.2m to 25m
• Velocity Measurement Range: 0.1 m/s to 10 m/s
• Beam Angle: 100° x 40°
• Communication: I/O, UART
• Default Baud Rate: 9600
• Operating Temperature: -40℃ to 85℃
• Dimensions: 26mm x 30mm

• C4001 mmWave Presence Sensor 25m × 1
• 5-pin header × 1