Gravity: mmWave C4001 24GHz Human Presence Detection Sensor (12 Meters, I2C & UART)

The Gravity: C4001 is a 24GHz millimeter-wave radar sensor designed for precision human presence, motion, distance, and speed detection up to 12 metres. Unlike traditional infrared sensors, it reliably detects stationary individuals whether sitting or sleeping, without being affected by ambient light, temperature shifts, or acoustic noise. It is ideal for makers and students building smart home automation, security, and environmental monitoring projects using Arduino, ESP32, or Raspberry Pi.

Static and moving presence sensing

Operating at 24GHz, this mmWave module detects static human presence up to 8 metres and human motion up to 12 metres across a wide beam angle. Because it tracks micro-movements, it reliably maintains detection when occupants are seated or sleeping without triggering false negatives.

FMCW distance and speed measurement

Using Frequency Modulated Continuous Wave radar technology, the C4001 delivers continuous real-time distance and velocity tracking. It accurately measures target distances from 1.2 to 12 metres and records movement speeds between 0.1 and 10 metres per second.

Versatile mounting configurations

The module accommodates multiple installation methods including top, bottom, horizontal, and downward-tilted orientations to suit different room layouts. Correct orientation ensures optimal coverage across its 100 by 80 degree detection field.

Dual I2C and UART connectivity

Equipped with a Gravity PH2.0 4-pin connector, the sensor supports both I2C and UART communication protocols at 9600 baud. It operates on 3.3V or 5V logic, making it directly compatible with Arduino, Raspberry Pi, ESP8266, and ESP32 microcontrollers.

All-weather anti-interference design

Measuring just 22 by 30 mm, the sensor operates reliably across an industrial temperature range of -40 to 85 degrees Celsius. Its millimeter-wave signal is immune to common environmental disturbances such as dust, humidity, haze, temperature changes, and ambient noise.

Downloads & documentation

• Product wiki (DFRobot)