Special Passive Infrared Applications (SPIRA) is a research project specializing in low-cost, low-power and high-accuracy passive infrared occupancy sensors. SPIRA can be integrated into residential "smart home" and commercial HVAC systems in order to provide greater energy savings, while simultaneously addressing user requirements for cost, privacy, and usability.
Our innovation relies on the use of an "optical chopper' which acts like a clock hand that periodically interrupts the incident infrared (IR) radiation to the sensor and allows the device to detect both stationary and moving individuals. The electronic chopper operates in the 9-11 micrometer long wave IR region, where human skin radiates the most. Our first successful prototype was the RO-PIR (rotating passive infrared) sensor. In which we were able to detect human presence in the lab while remaining stationary.
Our team will evaluate several approaches for the chopper, such as new low-power liquid crystal technology with no moving parts. We will apply new signal processing techniques and machine learning to the infrared data, enabling differentiation between pets and people, and potentially sleep vs. active states.
The Stony Brook team received an award from ARPA-E’s Saving Energy Nationwide in Structures with Occupancy Recognition (SENSOR) program, which supports innovative and highly accurate presence sensors and occupant counters that optimize heating, cooling, and ventilation (HVAC) of buildings while reducing cost and slashing energy use.