Digital thermometer needs to collect temperature data and display temperature data
The main function of the digital thermometer is to display the temperature data collected. Although the function is very simple, the collection of temperature data and the drive display temperature need the assistance of a single chip computer.
Collecting temperature data
NTC can be used as a temperature sensor to collect temperature data. NTC is a negative temperature coefficient thermistor, the higher the temperature, the smaller the resistance, its resistance value has a certain relationship with the temperature. It can use a fixed resistance and NTC to form a partial voltage, the single chip computer through AD conversion to obtain the voltage value, and calculate the current temperature through the voltage value. The smaller the tolerance of the fixed resistance and NTC, the more accurate the temperature will be; The higher the precision of AD conversion, the more accurate the data obtained.
Van=5V (1 R2\/R1). After measuring the voltage of AN, the microcontroller can calculate the resistance value of NTC (R1), and calculate the current temperature according to the relationship between the resistance value of NTC and the temperature.
Digital temperature sensor can also be used to collect temperature data, digital temperature sensor is more accurate, it has a built-in acquisition, calculation of temperature data chip, can directly output temperature data, single-chip microcomputer through I2C\/SPI interface can directly read the temperature data.
Display temperature
After the temperature data is obtained, the temperature can be displayed with a digital tube or LCD. A simple digital tube or LCD is generally composed of seven segments to form an \"8\" word, and the corresponding number can be obtained as long as the corresponding segment is lit. For example, lighting the A\/B\/C\/C\/G segment on the digital tube will display the number \"3\".
However, the light of the digital tube or LCD segment painting, also need to participate in the microcontroller, taking the digital tube as an example, a single chip through the transistor can drive the digital tube display. According to the temperature change, change the number displayed on the digital tube can be.
Of course, the above is only the prototype of the digital thermometer, the general digital thermometer will come with other functions; Such as temperature unit conversion, temperature data recording, humidity, time, alarm clock, alarm and so on.
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