The Design Of Temperature System Based On L298N In Biosensor

The biosensor is an instrument which is sensitive to biological material and changed the concentration signal to the electrical signal for measurement. It is an analysis tool and system for recognizing immobilized biological material and transducer. The biosensor has the function of receiver and transducer. This method is also used to measure the refractive index (RI) of solution. The measurement of refractive index is widely used for probing environment and biological pharmacy, but the problems to be solved are the rapid measurement and measurement of micro-concentration. Several methods, including diffraction, interferometry, wave guiding and Plasmon sensing, can be used to detect micro-concentration and have highly detection limit. But they all have shortcomings. In the measurement the stable temperature system is necessary. In this paper, we design a micro-interferometric backscatter detector (MIBD) based on backscatter for measuring the refractive index in the solution and mainly describe the temperature system used in the MIBD.The temperature system used in the MIBD is contained temperature sensor, signal circuit of temperature difference, driving circuit for TEC, control circuit for single chip processor, sofiware of real-time measurement and design of mechanical structure. In this paper we explain the principle of TEC based on semiconductor materials and optical measurement, present the temperature circuit and measurement principle of the MIBD system. In this system, we use the Pt100 as the temperature sensor. We use the operational amplifier and ADC (analogue-to-digital converter) as the collection of temperature signal. Using this system, the temperature accuracy was controlled to reach 0.1℃between 20℃and 40℃. Finally we accomplish the MIBD system for measurement of refractive index.