MEMS optical position sensor for sun tracking

We demonstrate a sun tracking sensor fabricated in the MultiMEMS SensoNor process. The sensor uses a quadrant photodetector to determine the position of a projected shadow. Differential measurement of pairs of photodiodes allows simultaneous dual-axis readings. The sensing structure was manufactured in the commercial MultiMEMS process, so it can be easily reproduced in large quantities. The device was tested from -45° to +45° to verify performance. Results show a linear correlation between a mapped output and angle of incident light with an R² value of 0.995. The small size, robust structure, and minimal post-processing make it well-suited for sun tracking applications.