DFRobot C4001 Radar Sensor - 24 GHz mmWave, up to 25 m, UART

DFRobot C4001 mmWave Radar Sensor 24 GHz - Presence and Motion Detection up to 25 m

The DFRobot C4001 is a millimeter-wave radar sensor. It detects whether someone is in a room - even if they are sitting still, reading, or sleeping. This is exactly where conventional PIR motion detectors fall short, since they only respond to movement.

The module operates at 24 GHz and uses FMCW modulation. This allows it to detect not only presence, but also measure a target's distance and speed. The sensor detects presence up to 16 m, and motion and distance up to 25 m. Radar operates independently of light, dust, fog, temperature, and ambient noise.

To get started, the digital switching output is all you need: it switches on as soon as someone is detected - no serial programming required. For more advanced use, read measurements such as distance and speed via the UART interface and configure sensitivity and detection range. This makes the sensor suitable for both introductory classroom projects and advanced maker applications.

Highlights

• Presence detection up to 16 m, motion and distance detection up to 25 m
• Detects stationary people, not just movement
• Distance measurement from 1.2 m to 25 m, speed measurement from 0.1 m/s to 10 m/s
• Detection range of 100° horizontal x 40° vertical
• Unaffected by light, dust, fog, temperature, and noise
• Two output options: UART for measurements and configuration, digital switching output for simple applications
• Operates at 3.3 V or 5 V, compatible with Arduino, ESP32, and Raspberry Pi
• Compact 26 x 30 mm board with integrated antenna

Applications

• Lighting that stays on as long as someone is in the room
• Smart home and building automation, for example via ESPHome
• Classroom projects on sensors, radar technology, and automation
• Occupancy detection in rooms, workspaces, and hallways
• Distance and speed measurement in robotics and model-building projects
• Contactless activation of indicators, announcements, or displays

Technical specifications

Package Contents

• 1x DFRobot C4001 mmWave Radar Sensor 24 GHz (SEN0609)
• 1x 5-pin header