Master's Thesis: Design of a miniature laser measurement head based on BEA's ASIC

Abstract

BEA Sensors is a leading company in the design of detection sensors for automatic doors. One of its main goals is innovation. Their sensors are based on three different technologies: RADAR, LiDAR or active infrared. In this master thesis, the miniaturization of a LiDAR sensor is carried out. This sensor measures the time-of-flight of laser light pulses to determine distances. From the measurement of the dis- tance, it can be deduced whether a door should open or not. The miniaturized sensor performs single-point measurements and is based on BEA’s ASIC, which is responsible for measuring the time-of-flight. This work involves designing the electronic circuit schematic, the PCB, and the embedded software required for the sensor’s operation. To achieve the sensor’s miniaturization, rigid-flex PCB technology is used. This approach combines the use of a flexible PCB with that of a rigid PCB. This enables the integration of multiple interconnected PCBs around the optical block used for emitting and receiving the laser pulses. The resulting miniaturization of the sensor offers a new field of applications thanks to its small size, which is approximately four times smaller than typical sensors from BEA. It also enabled reducing the sensor’s consumption to 0.5W while keeping an equivalent accuracy (±1cm at 10m). Its reduced dimensions enable use in tighter areas, where BEA’s standard sensors cannot be easily deployed. For instance, this sensor may be well-suited for securing door pinch zones.