Which DFRobot mmWave Human Presence Sensor Should I Choose?

DFRobot offers several mmWave human presence sensors for different project requirements, from basic presence detection and Home Assistant automation to long-range sensing, fall detection, and sleep monitoring.

The key is not simply choosing the sensor with the longest detection range. Different models vary in detection capability, interface, operating frequency, software integration, and intended application.

This guide compares the current DFRobot mmWave sensor lineup and helps you choose the right model based on what you want to build.

Quick Answer: Choose by Application

If you already know your project goal, start here:

DFRobot mmWave Sensor Comparison

For Home Assistant: Choose the Fermion: C4002 mmWave Human Presence Sensor

If your main goal is building room occupancy automation with Home Assistant, the Fermion C4002 is the most directly targeted model in the current DFRobot lineup.

Unlike a conventional motion-only trigger, the C4002 detects:

• Motion
• Micro-motion
• Stationary human presence

Its product page specifically describes detecting a person who is sitting, reading, typing, or sleeping.

Static presence detection reaches up to 10m, while motion detection reaches up to 11m.

More importantly for Home Assistant users, DFRobot provides a verified ESPHome YAML configuration. After deployment, the sensor can expose entities including:

• Occupancy
• Distance
• Energy

in Home Assistant.

The C4002 also allows the detection distance to be configured so the active sensing area can be adapted to the room layout. This can help limit detection to areas such as a sofa or workspace while reducing unwanted detection from adjacent spaces.

Choose the C4002 if:

• You are building with Home Assistant
• You want ESPHome integration
• Your goal is room occupancy rather than just motion detection
• You need to detect people who may remain stationary
• You are building smart lighting, HVAC, or occupancy automation

Key Specifications

• Frequency: 24GHz–24.25GHz
• Motion detection: up to 11m
• Micro-motion / stationary detection: up to 10m
• Detection angle: 120° × 120°
• Interface: UART + configurable OUT
• Light detection: 0–50 lux
• Operating voltage: 3.6–5.5V

For Long-Range Presence Detection: Choose the C4001 Long-Range Sensor

For projects where detection distance is the main requirement, the long-range C4001 provides the largest listed sensing range in the current DFRobot mmWave lineup.

It supports:

• Human presence detection up to 16m
• Motion detection up to 25m
• Distance measurement from 1.2m to 25m
• Velocity measurement from 0.1m/s to 10m/s

It uses 24GHz FMCW radar and can detect human presence as well as motion.

The existing product page highlights applications including:

• Large living spaces
• Long corridors
• Smart bathrooms
• Security monitoring
• Occupancy-based energy management

The product page also states compatibility with Arduino, ESPHome, and Home Assistant.

Choose the C4001 Long-Range Sensor if:

• You need substantially longer range than a typical room sensor
• You need presence detection across a large space
• You also need distance or velocity information
• You are building corridor, large-room, security, or energy-management projects

For Arduino or ESP32 Projects Requiring I2C: Choose the Gravity: mmWave C4001 Sensor

The Gravity C4001 is a good option when the communication interface is a key requirement.

Unlike the UART-focused long-range C4001, the Gravity C4001 supports both:

• I2C
• UART

It also uses DFRobot's Gravity PH2.0 connector.

The sensor is compatible with:

• Arduino
• Raspberry Pi
• ESP32
• ESP8266

Its two detection ranges should again be distinguished:

• Human presence: up to 8m
• Motion: up to 12m
• Distance measurement: 1.2–12m
• Velocity measurement: 0.1–10m/s

Choose the Gravity C4001 if:

• You need I2C
• You prefer the Gravity connector ecosystem
• You are building with Arduino, ESP32, ESP8266, or Raspberry Pi
• 8m human presence / 12m motion range is sufficient
• You also need distance or velocity measurement

For Fall Detection: Choose the C1001 60GHz Sensor

The C1001 serves a different role from the C4001 and C4002 sensors.

Rather than focusing primarily on general room occupancy, it includes built-in functions for:

• Human presence detection
• Fall detection
• Sleep monitoring
• Breathing detection
• Heart-rate detection

For fall detection, the sensor uses its built-in algorithm to recognize human postures, including a person lying down.

The product page states that it can report:

• Fall incidents
• Duration of immobility
• Periods of physical inactivity

The sensor has a listed maximum detection distance of 11m and a radar detection angle of 100° × 100°.

Because the system operates without capturing images, the C1001 can be used in privacy-sensitive environments such as bedrooms and bathrooms.

Choose the C1001 if:

• Your project specifically requires fall detection
• You want a camera-free sensing approach
• You need to detect human presence as well as falls
• You are developing an elderly-care or indoor safety prototype

Important

The C1001 is not a certified medical device and is not intended for diagnostic or therapeutic use.

For Sleep, Breathing, and Heart-Rate Monitoring: Choose the C1001

The C1001 also includes a dedicated sleep monitoring mode.

According to the current product specifications:

• Sleep detection distance from the chest: 0.4–2.5m
• Breathing and heart-rate detection distance: 0.4–1.5m
• Breathing measurement range: 10–25 breaths/min
• Heart-rate measurement range: 60–100 beats/min

Its sleep monitoring mode tracks human presence and movement and analyzes body movement and respiratory-rate changes during the night.

Choose the C1001 if:

• You are building a contactless sleep-monitoring prototype
• You need breathing-rate output
• You need heart-rate output within the sensor's stated measurement range
• You want sleep-related sensing without a camera

These functions should be treated as sensing and development capabilities rather than medical diagnostic functions.

For Simple Embedded Presence Detection: Choose the 24GHz Human Presence Sensing Module

This compact 24GHz FMCW module is intended for relatively straightforward embedded projects.

It can detect both:

• Moving humans
• Stationary humans

It can also output target distance information.

Its key specifications include:

• Detection range: 0.75–6m
• Measured blind zone: 30cm
• Detection angle: ±60°
• Distance resolution: 0.75m
• UART
• GPIO high/low-level output
• Operating voltage: 5–12V

The module has a narrow form factor with a width of 7mm, making it suitable for integration into devices where installation space is limited.

Choose this 6m Presence Module if:

• You need presence detection within approximately 6m
• UART or simple GPIO output is sufficient
• You want to embed the radar module into another device
• You do not require Home Assistant-specific integration, I2C, fall detection, or sleep monitoring

How to Choose: 5 Questions to Ask

1.Do You Need Home Assistant?

Yes → Start with the Fermion C4002 Sensor.

It has the clearest official Home Assistant integration in the current lineup, including ESPHome compatibility and a verified YAML configuration.

2.Do You Need Fall Detection or Sleep Monitoring?

Yes → Choose the C1001 60GHz Sensor.

Fall detection, sleep monitoring, breathing detection, and heart-rate detection are specific built-in functions of the C1001.

Do not assume that a general C4001 or C4002 presence sensor provides the same functions.

3.Do You Need the Longest Detection Range?

Yes → Consider the C4001 Long-Range Sensor.

It provides:

• 16m human presence detection
• 25m motion detection

This is the longest listed motion detection range among the DFRobot mmWave sensors compared in this guide.

4.Do You Specifically Need I2C?

Yes → Choose the Gravity C4001 Sensor.

It supports both I2C and UART and provides configurable I2C addresses of 0x2A / 0x2B.

5.Do You Only Need Basic Presence Detection?

Then you may not need one of the more application-specific models.

For shorter-range embedded sensing:

24GHz Human Presence Sensing Module: up to 6m, UART + GPIO.

For general room presence and Home Assistant:

Fermion C4002: 10m stationary presence / 11m motion.

For longer-range sensing:

C4001 Long-Range Sensor: 16m presence / 25m motion.

Choosing according to the actual sensing task is more useful than simply selecting the model with the highest maximum-distance number.

The most important distinction is not simply 24GHz vs 60GHz or 6m vs 25m. Start with the function your project actually requires—room presence, long-range sensing, interface compatibility, fall detection, or sleep monitoring—and then choose the sensor designed around that requirement.