STMicroelectronics STHS34PF80 infrared sensor

STMicroelectronics has launched the STHS34PF80, a novel human-presence and -motion detector to enhance security systems, home-automation equipment and IoT devices that typically use passive infrared (PIR) sensing.

The sensor contains thermal transistors that are designed to detect stationary objects, unlike conventional PIR detectors that require the detected object to be moving to produce a measurable response from the sensor. Also, while PIRs need a Fresnel lens to sense moving objects, ST’s detector enables simpler, lens-free construction.

The low power sensor is made using a combination of CMOS chip fabrication, silicon micromachining and low-voltage circuit design capabilities.

Featuring a smart algorithm for presence and motion detection, the infrared sensor targets alarms and security systems, home automation, smart lighting, IoT devices, smart lockers and smart wall pads. Its lens-free range of 4 m and 80° field of view cover a large area in front of the sensor. With operating current of 10 µA, power consumption is less than a conventional PIR, and the 3.2 x 4.2 x 1.455 mm surface-mount package is suited to automated high-speed assembly. The sensor has high resistance to unwanted effects of direct lighting and immunity to electromagnetic interference (EMI).

Drivers for the infrared sensor are available on GitHub. In addition, a ready-to-use library for compensating and detecting presence of people or objects is available in the X-CUBE-MEMS1 software package. Users can quickly start running simple applications, taking advantage of the STHS34PF80 and testing the results to begin creating an application.

The infrared sensor also contains thermal MOSFETs (TMOS) that are sensitive to the heating effects of infrared radiation incident on their gates, as well as digital readout circuitry integrated on the same chip using ST’s silicon-on-insulator (SOI) CMOS technology. The SOI’s architecture facilitates micromachining with ST’s MEMS (micro electromechanical systems) processes to thermally isolate the TMOS for accurate temperature sensing.