A Small Thickness Measurement System Based on PSD and FPGA

Considering that the requirement of industrial manufacture, a small thickness measurement system based on PSD and FPGA is presented. It takes S3931 PSD of one dimension as position detection device, which is made by Hamamatsu in Japan, A FPGA produces logic control signals for the whole system, An AT89S51 single chip works as the core processor of the system. By two laser triangulation, the small displacement is converted to differential voltages, and after amplification and A/D transformation, 8-bit parallel data is send to single chip from FPGA by external interrupts, and the final calculation results output to the LCD display module. After digital micro meter calibration, we get the small thickness. Experiments show that the detection accuracy of the system is not less than 10um.