Design Of A Portable Fluorescent Optical Fiber Measuring Instrument For PO₂ Based On DSP And STM32

Measuring oxygen content has become one of the most important things in many scientific researches and practical applications in recent years,such as biotechnology,marine science,biology,chemical analysis,food industry,and in medicine.At present,there are three major methods known for determination of oxygen levels.These are the classical Winkler titration,electroanalytical and photo-chemical methods.Considering operation,real-time,reliability,the consumption of object and so on,we acknowledge that there are many disadvantages in these methods.However,Fluorescence fiber oxygen sensor overcomes the above shortcomings,and meanwhile makes remote sensing and instrumentation miniaturization come true.In this paper,we present and implement a portable,real-time,low-cost,miniaturized fluorescence fiber biomedical oxygen sensor and detection system,which based on the core-controller DSP and STM32,realizing the real-time optical detection for the oxygen concentration.The principle is to achieve an oxygen partial pressure by measuring the fluorescence intensity and lifetime.In this system,the excitation light is produced by driving the blue LED at first.Secondly,the excitation light transmitted through the optical fiber to the oxygen-sensitive film prepared by the Ru?dpp?3²⁺,the organic modified sol-gel?ormosil?,and the polyurethane hydrogel.Then the fluorescence phase shift signal is generated between the absorption peak of the sinusoidal excitation signal and the emission peak of the oxygen-sensitive indicator.At the same time,the fluorescence phase shift signal is constantly processed by signal processing circuit and digital quadrature phase locked signal conditioning system which is based on DSP.At last,the system uses the STM32 controller to calculate and display the real-time of pO₂.Based on the research background and development status of fluorescence optical fiber sensor,the significance and application prospect of this project are discussed in this paper.In summary,the contents of this paper is divided into the following sections:?1?The introduction and simulation of the fluorescence fiber optic sensor pO₂ and the whole system is modular analysis.We build desired emulation platform according to the module,and simulate and analysis each module,we can verify the entire system works reliability and stability.?2?According to the design requirements,and the detection principle and the working performance of the system,we select the appropriate sensor materials,analysis theory and repeated test trial and error,and synthesis of oxygen-sensitive membrane sensor required.And according to the respective requirements,we will optimize the design in order to meet the design requirements of the system.?3?In this paper,we utilize digital phase-locked demodulation technology to realize real-time fluorescence signal processing and analysis.According to system design requirements to select the appropriate DSP digital processor and the corresponding system controllers and modules required to build systems to achieve real-time signal processing circuit processing system,working reliability and design miniaturization.?4?Testing the entire system as a whole,we will further optimization according to the experimental results and design requirements.The goal is to further expand its application areas and diversify application requirements.