A Data Acquisition And Processing System For Spectrometer Based On STM32MCU

The spectrometer can take advantage of the characteristic spectrum of thesubstance, and make the qualitative and quantitative analysis on its composition andcontent, the spectrometer is applied in almost all fields of science, such asmetallurgical, geological exploration, environmental protection and marinedevelopment, etc. With the development of the modem techniques, miniaturespectrometer has become a research focus worldwide and is the trend of thespectrometer. As an important part of spectrometer, data acquisition and processingsystem is one of the key techniques to realize miniaturized request.In this thesis, a detection system for miniature spectrometer is developed, whichcan realize spectral data acquisition, processing, transmission, storage and imagedisplay. To get a high resolution spectral data, a3648pixels linear CCD, that isTCD1304, is chosen as the detector. Through the optical system, the light expose tothe CCD receive interface, the spectral data that after the CCD conversion, are givento the low-noise amplifier LT6231for strengthening, and than send to themicroprocessor within the analog to digital conversion. The microprocessor used inthe system is ARM-based32-bit STM32high-density performance line MCU, whichbuilt-in multi-channel12-bit ADC that can realize the spectral data acquisition; andthe data can be processing by the software to obtain14-bit accuracy. The data arestored in SD card that in the system, while transported into the computer thought theUSB interface. The software about spectral collection and analyzing, has beenachieved many functions such as spectral wavelength calibrating, spectrum displayingand storage. During the development, the following works have been finished:1. According to the characteristics of spectrometer detection system, itestablish the corresponding overall implementation program, including theselection and location of CCD; the selection and functions ofmicroprocessor; the display and functions of application software on the computer.2. The hardware circuit of the detection system is designed, including CCDdriving circuit, the collection circuit of analog to digital conversion, thetransportation circuit of USB, the memory circuit of SD card and the basicconfiguration of the microprocessor circuit.3. The software based on the microprocessor is realized, which is able toimplement the driving signal of CCD, control the integration time of CCD,produce the trigger signal of analog to digital conversion for dataacquisition, realize the driving of underlying USB, which can communicateto computer by the software.4. The application software on the computer has been achieved, which is basedon the Visual Studio2008integrated development platform. The applicationcan receive spectral data from the microprocessor thought the USB, andfinish wavelength calibrating, and display the spectral image aftersmoothing and filtering the data.The schematic and PCB is designed with Portel99se, and the design of software,debugging and final realization of each logic module is completed using RealViewMDK. To test the quality of the detection system, the WDM1-2gratingmonochromator in our laboratory is used, which has the Czerny-Turner opticalplatform, and the low-pressure mercury lamp and low-pressure sodium lamp aremeasured; it is the result that can accurately distinguish three mercury lampcharacteristic lines of green and yellow, and the location of the double sodium yellowlines. The resolution of CCD pixel is0.019nm. Experimental results show that thedetection system can be successfully completed spectral data acquisition, processingand display, and reached a high spectral resolution.