LD1115H 24 GHz Human Presence Sensor Module with TTL Serial Communication for MicroMotion Detection Overview The LD1115H is a compact 24 GHz radar sensor module designed to detect human presence and micro motion. It communicates over TTL serial UART for straightforward integration with microcontrollers and single board computers that support TTL UART. The module is intended for projects and products that require reliable, contactless presence detection in small to medium indoor spaces. Key benefits Detects micro motion: Sensitive to small movements such as slight gestures or breathing, enabling presence sensing in lowactivity situations. Easy integration: TTL serial communication simplifies connection to common development systems and embedded controllers, reducing development time. Compact and lightweight: Small PCB form factor suitable for embedding in prototypes, panels, and final devices where space is limited. Versatile mounting: Designed for ceiling, wall, or enclosure mounting to provide reliable coverage for occupancy and presence tasks. Contactless detection: Operates without line contact, preserving hygiene and reducing mechanical wear compared to mechanical switches. Main functions and attributes Function: Human presence detection and micromotion sensing using 24 GHz radar technology. Communication: TTL serial UART output for presence and motion event reporting. Model: LD1115H. Size and form factor: Compact PCB module optimized for integration into devices and systems. Construction: Standard electronic components on PCB suitable for embedded applications. Performance: sensitivity to micro movements for applications such as occupancy sensing and touchless activation. Compatibility and integration Interfaces with microcontrollers and single board computers that support TTL UART. Works with common development workflows for rapid prototyping and product integration. Minimal wiring: typical connections include power, ground, TX, and RX for serial communication. Practical applications and scenarios 1) Smart lighting and energy management Mount the LD1115H in corridors, restrooms, or meeting rooms to enable lights to turn on only when presence is detected. Its sensitivity to small motions helps avoid falseoffs when occupants are stationary for short periods. 2) Occupancy sensing for HVAC and facility management Use the module to provide realtime occupancy signals to building systems for more efficient heating, ventilation, and air conditioning control. The module helps systems respond to actual presence rather than scheduled assumptions. 3) Touchless control and security Integrate the LD1115H into access control panels, automatic doors, or interactive kiosks to trigger actions when a person approaches. Its contactless detection supports hygienic operation and durable performance. Installation and usage tips Place the module where it can cover the intended area, such as a ceiling or wall location for room occupancy, or near an entry point for approach detection. Ensure reliable serial connection by using appropriate voltage levels for TTL UART on the host controller. Test orientation and mounting height to optimize detection coverage for the specific environment. Why choose LD1115H The LD1115H provides a practical combination of 24 GHz radar sensitivity and TTL serial ease of use in a compact module. It solves common challenges in presence detection by sensing small movements without physical contact and by offering a simple integration path into embedded systems and control architectures. What is included LD1115H sensor module with TTL serial interface on a compact PCB. Technical note This module uses 24 GHz radar technology and reports presence and motion events over TTL serial. Consult your system documentation for proper UART voltage levels and wiring during integration.