The D6T non-contact MEMS thermal sensor from Omron can reliably detect the presence of humans in an area, even if they aren’t moving (see the figure). This type of thermal sensor is an alternative to pyroelectric sensors, or PIR detectors, in security and building automation applications. While standard thermal sensors are only able to measure temperature at one contact point, the new sensor can measure the temperature of an entire area without contact.
The D6T thermal sensors combine a MEMS micro-mirror structure for efficient IR radiation detection with a high-performance silicon lens to focus the infrared rays onto its thermopiles. Proprietary ASICs then make the necessary computations and convert sensor signals into digital I2C outputs. All components were developed in-house and are fabricated in Omron’s own MEMS facilities. The result is high ±1.5°C accuracy with excellent noise immunity (measured as noise equivalent temperature difference) of 140 mK.
Omron says sensitive IR temperature sensors, like the D6T, provide a more reliable basis for switching off lighting, air conditioning, and other services when the space is empty. Conventional sensors often fail to distinguish between an unoccupied space and a stationary person. This feature is a particular issue in healthcare system design, when detecting the presence of bed-bound patients in a room. Unusual changes in temperature can also be used in other ways, such as to detect line stoppages, identify hot spots before a fire breaks out, or in clinical applications to check whether a patient has left the bed.