Temperature Sensor Based on DS1820

An 8-pin microcontroller is used to build an accurate, small, and fast temperature sensor that will be used for logging temperature through a serial port.

The device is being powered by the serial port of the computer which eliminates the need for external supply. The serial port is also responsible for providing real-time data to the computer. There are no special programs required since the data can be processed easily. Four DS1820 temperature sensors can be interfaced where each has an absolute accuracy near 0.5°C and relative accuracy near 0.01°C.

The circuit can be identified by the built-in serial number and the cost is reduced due to the minimal parts count. The single-bit digital inputs can be assigned to the spare inputs while special versions can be made for exotic requirements such as additional sensors, long distance, low or high speed, or pedantic serial bus.

During the operation, the program fetches data from the sensors and sends it to the serial port repeatedly. The two protocols known by the program in the microcontroller are the serial protocol expected by the computer and the one-wire bus used by the temperature sensor for human reading.

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