Hi-Link LD1115H 24GHz Micro-Motion Radar Module - TTL Serial Interface

Standard motion detection (PIR) senses gross movement across infrared heat zones. The LD1115H's 24GHz micro-motion detection uses Doppler radar to sense subtle, sub-wavelength movements like chest motion from breathing or finger twitches, providing presence sensing even when a person is largely stationary, which is critical for accurate occupancy monitoring.

Connect the module's VCC (3.6-5V) and GND to your microcontroller's power pins. The TX pin of the module connects to an RX pin on your Arduino/ESP32 for receiving ASCII data packets over TTL serial. You can also configure a separate output pin to act as a simple high/low trigger. Use the Serial library to parse the human-readable data strings for presence status and signal strength.

Yes, the module is configurable via serial commands sent to its RX pin. You can adjust parameters like the detection threshold, hold time (how long the output remains active after detection), and the operating mode. Refer to the Hi-Link datasheet for the specific command set to tailor the sensor's performance to your application's environment and required sensitivity.

The LD1115H is designed for low-power operation suitable for always-on IoT applications. Exact current draw varies with configuration and detection activity, but it typically consumes tens of milliamps during active sensing. Its 3.6V minimum operating voltage also makes it compatible with battery-powered projects using a 3.7V Li-ion cell.