A Miniaturized Optical Sensor for Fire Smoke Detection

We present an innovative optical smoke sensor based on a novel technique that we call `single particle light-scattering imaging'. A diffraction pattern is created by the interaction of a light beam with fire smoke particles [1] [2]. This pattern is then collected by a holed CMOS image sensor and can be interpreted to determine the optical proprieties of fire (or non-fire) particles. This technique allows us to differentiate the type of fires at very low concentration of smoke particles and to avoid the usual false positives.We describe the sensing technique, the architecture and fabrication of this novel sensor as well as characterization results, which are in good accordance with our theory-based predictions. In particular, we show that it is possible to differentiate calibrated particulates of different sizes.