Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Operating Frequency	79 GHz
Detection Principle	Millimeter Wave Radar (FMCW)
Sensing Type	Non-Contact
Interface Protocol	UART / TTL
Supply Voltage	5.0V DC ±5%
Operating Current	< 60 mA
Detection Range	0 - 15 meters (adjustable)
Beam Angle	Horizontal 10°, Vertical 10°
Operating Temperature	-40°C to +85°C
Dimensions	25mm x 25mm x 3mm

6 reviews

Anonymous

Mar 31, 2026

Rating: 5/5

Reliable for harsh environments

Deployed three of these units in an outdoor agricultural setup. They have survived rain, dust, and temperature swings without issue. The non-contact nature means zero maintenance so far. Highly recommended for anyone building robust level sensing solutions.

Anonymous

Mar 23, 2026

Rating: 5/5

Solved our chemical tank monitoring issue

We needed a sensor that wouldn't react with mild acidic solutions. Since this radar module doesn't touch the liquid, it was the perfect solution. Installation was easy, and the readout is consistent. Will be ordering more for our other production lines.

Anonymous

Mar 20, 2026

Rating: 5/5

Compact and powerful

Impressed by the small form factor considering the performance. I am using this for a flood detection project near a riverbank. The ability to detect level changes without touching the water prevents biofouling. Documentation could be slightly more detailed, but the sample code helped get it running quickly.

Anonymous

Mar 18, 2026

Rating: 5/5

Excellent precision for industrial tanks

We integrated this LD7901B module into our prototype water storage monitoring system. The non-contact feature is a game changer as it eliminates corrosion issues common with probe sensors. Setup via UART was straightforward, and the data stability is impressive even with surface agitation.

Anonymous

Mar 17, 2026

Rating: 4/5

Good value for research projects

Purchased this for a university thesis on fluid dynamics monitoring. The accuracy is sufficient for our needs, and the price point is reasonable compared to industrial-grade alternatives. Just ensure your microcontroller can handle the UART baud rate correctly.

Anonymous

Mar 11, 2026

Rating: 4/5

Great module, needs careful calibration

The sensor works very well for detecting water levels in large containers. It took some time to tune the filtering parameters to ignore false positives from splashing, but once configured, it has been rock solid. The 79GHz frequency provides much better resolution than older 24GHz modules I've tested.

5 FAQ

Q: What is the maximum update rate for the distance data?

A: The standard output refresh rate is configurable via the UART command set, typically ranging from 10Hz to 50Hz depending on the selected detection range and filtering settings. Please refer to the AT command manual for specific configuration instructions.

Q: Can this sensor detect water through a plastic tank wall?

A: Yes, the 79GHz millimeter wave radar can penetrate non-metallic materials like plastic or glass. However, the wall thickness and material density may affect signal strength, so we recommend testing with your specific tank material to ensure optimal range.

Q: Does foam on the water surface affect the reading accuracy?

A: Heavy foam can attenuate the radar signal slightly, potentially causing minor fluctuations in the reading. However, the LD7901B includes digital filtering algorithms that help stabilize the output. For thick foam layers, you may need to adjust the sensitivity thresholds.

Q: Is there a library available for Arduino or ESP32?

A: We provide a basic C-language demo code and communication protocol documentation on our GitHub repository. While there is no official pre-compiled Arduino library yet, many users have successfully created their own drivers based on our provided examples.

Q: What is the power consumption in sleep mode?

A: The module supports a low-power sleep mode which reduces current consumption to approximately 10µA. It can be woken up via a specific UART command or a hardware trigger pin, making it suitable for battery-operated applications.

Explore your interests

STC32G12K128 STC8H8K64U Microcontroller Small System Core Board Development Board Emulator

$16.50

Youxin Electronics_STM32H743IIT6 Core Board System Board Learning Board STM32 Development Board

$118.00

Arduino DUE Development Board 32-bit ARM Controller A000062 Italian Official Original Import with Cable

$299.00

Ultrasonic Sensor HC-SR04 Ultrasonic Distance Measuring Module Bracket US015-025-026-100

$3.16

Serial SHT20 Chip Temperature and Humidity Sensor Test, SHT30 Chip Measurement and Monitoring Module by Viter Intelligence

$11.00

High-Speed Yabo Smart Raspberry Pi 4B Motherboard Development Board Accessories RaspberryPi 2G/4G/8G RAM Py

$494.30

Magnetic Circular Counting Chips, Two-Sided Flip Coins for Elementary Math, Kindergarten Early Education, Ten-Frame Matrix, Addition/Subtraction within 10 & 20, Teaching Tools

$11.90

3-Wire/4-Wire Flame Sensor Module, Fire Source Detection with IR Receiver, Flame Detection and Alarm

$1.08

SANSI White Label Class A Glass Graduated Cylinder C18 Micro-Precision Demulsification Cylinder with Scale Measurement Includes Certificate Ground Joint Stopper Hexagonal Bottom Borosilicate Glass Lab Equipment

$3.68

EV2400 Battery Unlock Fuel Gauge Programmer MSP430 HPA500 Evaluation Module Interface Board SMBus

$323.00

Cube Three-View Teaching Aid with Grid - 3D Geometry Observation Tool for Grades 4-5 Math (2cm Cubic Blocks Set)

$15.10

OrangePi Orange Pi Zero3 Zero 3 Development Board Allwinner H618 Orange Pi

$228.00

Digital 38KHz Infrared Receiver Transmitter Head Sensor Module Electronic Building Blocks Robot Infrared Communication Remote Control

$2.29

12V Stable Version Light-Control Switch No-Light Sensing with Extension Cable Photoresistor Plus Relay Module

$49.20

STM32 Smart Car 51 Microcontroller Arduino Obstacle Avoidance Chassis Kit Mecanum Wheel Robot Car

$40.80

Tech Small Production Small Invention DIY Piano Electronic Keyboard Real Playable Science Small Handmade DIY Materials

$33.00

HX711 Pressure Sensor Module Electronic Scale Bracket Weighing DIY Scale Pan Tray Set 5/10/40kg200

$3.28

Transparent 3D Geometric Model Perspective Decomposition Graphic Teaching Aid, Complete Set for Elementary Grades 1-6 Math

$6.80

Thin Film Pressure Sensor Display, USB Rechargeable Flexible Resistive Pressure Digital Display Module, Wide Range Wireless

$20.00

E18-D80NK Infrared Photoelectric Switch Diffuse Reflection Obstacle Avoidance Sensor Module 3-80CM

$12.60

LAN8720 Module Network Module Ethernet Transceiver RMII Interface Development Board Xinwei Electronics

$7.85

STC15W408AS Core Board Minimum System Board 51 Microcontroller Development Board TTSOP20 Learning Board

$18.47

New Version MEGA2560 R3 Development Board, Improved MEGA2560 R3 with Sensor Expansion Board

$13.68

Gradient Visual Illusion Kit: Electric Rotating Assembly Toy for Maker DIY, Paintable Handmade Model

$8.72

51/AVR Microcontroller Core Development Board STC89C52RC/51MCU Experiment Board/ATMEGA32 Learning Board

$37.90

[Trial Pack] Xianlang Complete Cat Treat Sticks Meal Packs Main Course Cans Freeze-Dried Cat Food Sample Snacks Gift Set

$15.00

5A Range Current Transformer Module Voltage Sensor Single-Phase AC Active Output Current Transmitter

$5.06

Foldable Clothes Drying Rack Floor Standing Home Balcony Bedroom Hanging Clothes Quilt Drying Artifact Outdoor Cooling Rod Indoor Drying Rack

$47.10

Metal Detector Module Non-Contact Metal Induction Sensor Detection Module Metal Detector

$8.70

RV1103 Miniature Linux Development Board: RISC-V Vision and AI with Ethernet Port

$53.10

For Arduino Development Board R3 Mainboard Microcontroller Module Kit Programming Learning Board Sensor Suite

$78.00

Xuefen Geometry Stamping and Tracing Set for Grades 1-2, 3D and 2D Ink Pads, Math Learning Tools, Cube and Cuboid Models

$4.51

Rubber Tire Toy 4WD Smart Car Wheels Car Model Robot Accessories (Suitable for 2mm Axle)

$0.50

AHT10 High-Precision Digital Temperature and Humidity Sensor Measurement Module I2C Communication Replaces sht20

$7.88

Digital 38KHz Infrared Receiver/Transmitter Head Sensor Module for Electronic Building Blocks Robots, Infrared Communication Remote Control

$2.80

51 MCU Minimum System STC89C52 DIP40 Through-Hole Smart Car Main Control Board Learning Experiment

$19.80

Outdoor Adventure Kids' Insect Observation Box with Magnifying Glass, Boys & Girls Toy for Exploration, Butterfly Catching and Fish Scooping Tools

$7.80

MPU-9255 9-Axis Attitude 3-Axis Electronic Compass Accelerometer Gyroscope Magnetic Field Sensor Module

$13.42

Freeze-Dried Chicken Treats for Dogs: Nutritious Weight-Gain Breast Meat Chunks for Puppies – Teeth Cleaning, Grain Mixing, Universal Use

$3.90

Ningbo Keli SQB Cantilever Beam Weighing Module Sensor 100kg 500kg 1t 2t 3 Ton Small Floor Scale Inductor

$48.00