The Design Of PSD Signal Processing Circuit Base On MSP430

The Position Sensitive Detector is a kind of untouched and precise photoelectric sensor, which is applied in laser-distance-meter and collimator. As the preliminary work for the LRS(Laser Ranging System) base on position sensitive detector, this thesis designed a effective system circuit for the driver and data acquisition of PSD device.In this paper, a new scheme of double-PSD detection method based on MSP430F149 MCU is introduced. We have designed the A/D acquisition circuit, the circuit of amplifier, the circuit of protection, the RS485 communication circuit and the LCD display module. The software is programmed through IAR Embedded Workbench, which can help the system to work well, also can verify the real-time operation of the system. With the Ouguang HY0202 pin-cushion type PSD, we develop a new method of detecting system which has an optional difference-mode input signal from a pair of PSDs. The system can work in either single-PSD mode or double-PSD mode by using a switch. The new method combined the C430 language in software and has carried by MSP430F149 MCU. The result of the experiment shows that, the system can work out a steady and precise position data. By using the appropriate light source and optical filter, in single-PSD mode the position accuracy is 8.70% while in double-PSD mode, the position accuracy is 2.54%. Finally, the analyses results proved that this system is appropriate for the practical application. This paper studied the characteristics of the system and how to improve it.