Embedded System for Distance Measurement and Surface Discrimination Applications

The development of robotics and miniaturization has lead to the design of intelligent embedded sensors capable of measuring distance either on wide ranges or with high resolution. Yet, it is impossible to gather both information at the same time performing a single measurement. Furthermore, the enlightened surface type may be detected only under well-known experimental conditions. Computer processing is also often necessary to analyze the sensors data.In this paper, we report an embedded sensor capable of measuring distances with a resolution of 250 µm in a range of 2.7 m and of discriminating a wide variety of surface types. The embedded system is based on a phase-shift laser rangefinder, whose essential components are a Laser Diode (ML4412N) and its intelligent CMOS laser driver circuit, a CMOS Avalanche PhotoDiode (APD) and its transimpedance circuit and a CMOS Analog Neural Network.