The Design Of Signal Acquisition And Processing System For Spectrometer Based On Mobile Phone

Spectrometer is widely used in the qualitative and quantitative analysis of the material composition,Traditional spectrometers is bulky and expensive.It is not a commercial instrument.With the coming of the mobile Internet era,phone has become a most popular and essential personal equipment.The combination of smart phone and spectrometer has broad market prospects.This combination will make the spectrometer a universal instrument.In this paper,based on the Near-infrared(NIR)digital-micromirror-spectrometer developed in our laboratory,our goal of research is the combining signal processing system with the mobile phone.This thesis carries out scheme of the whole design after studying the NIR spectra characteristics of spectrometer and its application requirements,designs spectral signals for conditioning circuits and data for wireless transmission systems,meanwhile develops the mobile terminal spectrum software,finally,tests and verifies the hardware and software system,realizes signal acquisition and processing system based on mobile phone.The main research works are as follows:1 After the research on the miniature spectrometer and related products both home and aboard,propose the research objectives and main contents of this paper based on digital–micromirror-spectrometer and development trend.2 This paper analyzes the characteristics of the spectral signal acquisition and processing system and application requirements,and completes the selection of the whole system: select Bluetooth 4.0 as the design of the wireless communication;CC2541 wireless chip is adopted to realize the wireless transmission of data by low power Bluetooth BLE protocol,and determine the overall structure of this paper and the technical route.3 Determination of signal acquisition scheme based on mobile phone;Research the principle of lock-in amplifier,signal filtering and A/D conversion,according to the characteristics of the spectral signal and the requirements of the spectrometer determine the parameters of system.Complete the design of acquisition and conditioning circuit.4 Research on the scheme for wireless data transmission;Design of the hardware for wireless communication system which is used for Android smart phone;Research on the working principle of BLE protocol stack,complete the software design of CC2541 and mobile communication;Realize the wireless communication between spectral data acquisition system and smart phone.5 According to the functional requirements of the spectrometer software for the mobile phone,complete the overall design of the mobile terminal software system,develop the application software for Android mobile phone using JAVA in the Eclipse integrated development environment,program the software module function,and check the software system out.6 Finish the experiment and analysis,and build test platform which can test and verify the conditioning circuit,data acquisition module and Bluetooth communication module.The test experiment shows that the system can extract of weak signal,the sampling rate is 342 SPS,the wireless transmission speed is 1.4KPS,and its range of wavelength is 800-1900 nm,the resolution is 20 nm.