Smart occupancy sensors

Two Doppler radar occupancy sensor systems built with low-cost, low-power CC2530 are shown. One uses quadrature receiver, the other employs passive sensor node as receiver. The 12-minute experiment in which the quadrature sensor was exposed to a range of different presence/interference scenarios demonstrates such smart occupancy sensors can accurately detect the true presence occupancy by extracting the human respiratory and heartbeat signals. The study on sensitivity and power consumption for the passive node sensor under CW, modulated CW, and packet operation modes indicates the most cost efficiency and power efficiency can be achieved by operating the sensor under packet mode with an optimum output power level.