苏州大学本科生毕业设计（论文）附件：外文文献资料与中文翻译稿外文文献资料收集：苏州大学应用技术学院 11电子班（1116405023）陆妍松Temperature sensor and wireless moduleThis paper is designed a DS18B20 temperature data acquisition system, the system mainly consists of the microcontroller circuit and a digital sensor DS18B20 based. Software, we use keil software writing and debugging the program, the hardware side, we passed Proteus circuit simulation software, hardware, and test, the system is simple, low power consumption, through LCD1602 display the measured temperature. Temperature measurement accuracy of the system is relatively high, and stable communication with the microcontroller and PC.DS18B20 temperature sensor is American DALLAS Semiconductors latest smart temperature sensor, an improved, compared with the traditional thermistor temperature measurement devices, which can be read directly measured temperature, and can be based on actual requirements through simple programming 9 to 12 to achieve a digital readout mode.This design is a simple and practical small digital thermometer, the main components used with a sensor 18B20, microcontroller AT89S52 , one of four common cathode LED, resistor capacitor number. 18B20 support bus line interface, measurement temperature range -55 to +125. Within range-10 to+85, accuracy of 0.5. 18B20 poor accuracy of 2. Temperature directly to the scene bus line digital transfer, which greatly improves the systems interference. The site is suitable for temperature measurement in harsh environments, such as: environmental control, equipment or process control, temperature and other consumer electronics products. The digital thermometer design is divided into five parts, the main controller, LED display section, the sensor part, the reset part, clock circuit. That is part of the master controller microcontroller for storing programs and control circuit; LED display section refers to the four common anode digital tube, to display the temperature; sensor part, that the temperature sensor is used to collect temperature, temperature conversion; reset section that reset circuit. The total process measurement is the temperature sensor to the external environment, and converted spread SCM, SCM after treatment to determine the temperature was passed to the digital display. This design can complete temperature measurement range is -55to +128, due to limited capacity, can not achieve the alarm function.DS18B20 works as follows:DS18B20 internal oscillator is a low temperature coefficient of the oscillation frequency of the oscillator with temperature changes very little, providing a stable frequency count pulse counter 1. A high temperature coefficient of the oscillation frequency of the oscillator is very sensitive to temperature oscillator provides a frequency varies with temperature pulse counter 2 count. Which also implies counting door, the door is opened when the count, DS18B20 on the clock pulse after a low temperature coefficient of the oscillator is counted, and then complete the temperature measurement. Counting the door open time is determined by the temperature, coefficient oscillator, before each measurement, the corresponding first base were placed in -55and subtraction counter a temperature register, subtraction counter 1 and the temperature registers are preset in the corresponding to a base value -55. Subtraction counter 1 low temperature coefficient of the crystal pulse signal generated by subtraction count down counter when a preset value reduced to zero value of the temperature register will add a subtraction counter preset 1 will be re-loaded, subtraction counter a re-start of the low temperature coefficient crystal pulse signal is counted, so the cycle until the count down counter 2 to 0:00, stop accumulating temperature register value when the temperature registers is the measured temperature value. As long as the count has not closed the door to repeat the process, until the temperature reaches the measured temperature value register value, which is the principle of DS18B20 temperature. In addition, due to the DS18B20 single wire communication is done sharing his strict concept slots, so the timing is very important to read and write.DS18B20 internal comparator to quantify the way to determine the temperature registers rounding the least significant bit. After two counter stops counting, the comparator will counter a count in the remaining value is converted to temperature values are compared with 0.25, if less than 0.25, the lowest bit temperature register is set to 0; if higher than 0.25, the lowest bit is set to 1; if greater than 0.75, the lowest bit temperature register is set to 0 and then carry. Thus, after comparing the value obtained after the temperature is the temperature of the value of the final register read, and its last representatives 0.5, rounding the maximum quantization error is 1/2LSB, namely 0.25. Temperature register temperature values expressed in n