Hi-Link LD1125H 24GHz Breathing Detection Radar Sensor Module - FMCW Modulation, Serial Output

The LD1125H operates from a 3.3V to 5V DC power supply. It draws approximately 80mA during operation. Ensure your power source can provide stable voltage within this range to guarantee proper sensor functionality and output signal integrity.

The module uses 24GHz FMCW radar technology to analyze micro-Doppler signatures. It is specifically tuned to detect subtle periodic movements, such as chest motion from breathing, allowing it to confirm human presence even when the target is not walking or making large gestures, unlike standard motion sensors.

The sensor outputs ASCII data strings via a 3.3V TTL serial (UART) interface. To connect to a 5V Arduino, use a logic level converter on the sensor's TX line. You can then read the data using a SoftwareSerial or HardwareSerial port and parse the predefined ASCII commands for presence status and distance.

The sensor provides two key range specifications: it can detect static human presence (via breathing) at distances greater than 4 meters, and it can detect moving targets at distances greater than 8 meters. The actual range can be influenced by installation angle, environment, and target size.

While 24GHz radar can penetrate certain thin, non-conductive materials like drywall or plastic, performance is highly dependent on material thickness and composition. It is designed for line-of-sight or through-enclosure detection in controlled scenarios, not for reliably sensing through standard building walls.