COVER STORY
Unlocking the future of sensing Advanced low-power, high sensitivity IR sensing for presence and motion detection
In a world increasingly driven by automation, intelligence, and energy efficiency, the ability to detect presence and motion with precision and minimal power consumption is more critical than ever. Whether you’re building smart lighting systems, enhancing industrial automation, or developing next-generation security solutions, sensors with a compelling blend of performance, sensitivity, and simplicity – all in a compact, low-power package are a must. In this month’s edition, Andrew Pockson, engineering manager at Anglia, introduces the STHS34PF80, a cutting-edge infrared (IR) sensor from STMicroelectronics, designed to redefine how we perceive and interact with our environments. The article covers the technology behind the sensor, its key features and an overview of the applications it can address.
What Is the STHS34PF80?
The STHS34PF80 from STMicroelectronics is a factory- calibrated, uncooled infrared sensor built on advanced Thermal MOS (TMOS) technology, offering a transformative approach to motion and presence detection. Unlike traditional passive infrared (PIR) sensors, which rely solely on detecting movement and typically require bulky, custom-designed Fresnel lenses to focus infrared signals, the STHS34PF80 can operate with no lens at all and still detect human presence at a distance up to 4 metres, thanks to its highly sensitive MEMS-based architecture. This not only simplifies system design but also reduces component count and cost.
This broad spectral sensitivity ensures reliable detection in diverse environments, from residential spaces to industrial settings, without requirement for external optics in many cases or complex calibration routines.
The technology behind the innovation: TMOS At the heart of the STHS34PF80 lies TMOS (Thermal MOS) technology, a proprietary innovation by STMicroelectronics. This approach uses a MEMS-thermally-insulated gate to concentrate infrared radiation onto an isolated MOS transistor array. When IR radiation reaches the gate, it biases the transistors, enabling the sensor to detect temperature changes remotely.
This method offers two major advantages over conventional PIR sensors: Higher sensitivity: TMOS sensors can detect subtle temperature variations, making them ideal for applications where precision is paramount. Stationary object detection: Unlike PIR sensors, which require motion to trigger detection, TMOS sensors can identify the presence of still objects – opening up new use cases in security, automation, and energy management.
Key features
At its core, the sensor measures the infrared radiation emitted by objects within its 80° field of view, converting thermal energy into electrical signals via a thermally insulated gate structure. This information is then digitally processed by the onboard ASIC, which can be programmed to monitor motion, presence, or an overtemperature condition. The sensor can detect both moving and stationary objects with exceptional precision – an ability that PIR sensors fundamentally lack. The result is a sensor that can reliably identify human presence even when the subject is still, making it ideal for applications such as smart lighting, occupancy monitoring, and energy-efficient building automation.
Operating across a wavelength range of 5 µm to 20 µm, the STHS34PF80 is finely tuned to capture the thermal signatures of people and objects with remarkable accuracy.
10 October 2025 Components in Electronics
The STHS34PF80 is packed with features that make it a standout choice for developers and system integrators: High-sensitivity IR detection for both motion and presence Detection range up to 4 metres without the need for a lens (for objects ~70 x 25 cm²)
Integrated silicon IR filter for enhanced signal clarity 80° field of view, ideal for wide-area coverage Factory calibrated for plug-and-play integration Low power consumption – just 10 µA supply current Smart embedded algorithm for presence/motion classification
Digital interface via I²C or SPI Programmable Output Data Rates (ODRs) from 0.25 Hz to 30 Hz
One-shot mode for ultra-low-power applications Compact LGA 10-lead package (3.2 x 4.2 x 1.455 mm) RoHS and ECOPACK compliant
Performance that speaks for itself The STHS34PF80 doesn’t just promise performance – it consistently delivers it with precision and reliability. At the heart of its capabilities is an infrared sensitivity of 2000 LSB/°C, allowing it to detect even subtle variations in thermal radiation across its field of view. This high sensitivity is complemented by an impressively low RMS noise level of just 25 LSBrms, ensuring clean, accurate signal acquisition with minimal interference – critical for applications where false positives or missed detections can compromise system integrity.
In addition to its motion and presence detection capabilities, the sensor integrates a local temperature sensing function with an accuracy of ±0.3 °C, enabling it to serve dual roles in both environmental monitoring and predictive maintenance scenarios. Whether you’re tracking occupancy or monitoring heat anomalies in industrial equipment, this level of precision ensures dependable data for smarter decision-making.
Engineered for resilience, the STHS34PF80 operates across a wide industrial temperature range of -40°C to +85°C, making it suitable for deployment in both indoor and outdoor environments. From climate-controlled smart homes to rugged industrial facilities, the sensor maintains consistent performance regardless of ambient conditions. These specifications position the STHS34PF80 as a versatile and robust solution for designers seeking high-performance infrared sensing in compact, low-power systems.
Why choose the STHS34PF80 over PIR sensors? The STHS34PF80 offers a clear technological leap over PIR sensors, especially for applications that demand precision, compactness, and digital integration.
Applications across industries
The versatility of the STHS34PF80 makes it suitable for a wide range of use cases, below are some applications where this sensor is already being successfully deployed. Smart home and building automation: Detecting human presence in rooms to automate lighting, HVAC, and security systems. Unlike PIR sensors, the STHS34PF80
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