Project13.Analog Temperature
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Description
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This module is based on the working principle of a thermistor (resistance varies 
with temperature change in the environment).It can sense temperature changes in 
the surrounding and send the data to the analog IO of Arduino board. All we need 
to do is to convert the sensor’s output data into degrees Celsius temperature via 
simple programming, finally displaying it on the monitor.

It’s both convenient and effective, thus it is widely applied to gardening, home 
alarm system and other devices.

Specification
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- Interface type: analog
- Working voltage: 5V
- Temperature range: -55℃～315℃
- Size: 30*20mm
- Weight: 3g

Connect
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.. image:: /img/connect/13_bb.png

Code
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.. code-block:: c
    
    int ThermistorPin = A0;
    int Vo;
    float R1 = 10000; // value of R1 on board
    float logR2, R2, T;
    float c1 = 0.001129148, c2 = 0.000234125, c3 = 0.0000000876741; //steinhart-hart coeficients for thermistor
    void setup() {
    Serial.begin(9600);
    }
    void loop() {
    Vo = analogRead(ThermistorPin);
    // R2 = R1 * (1023.0 / (float)Vo - 1.0); //calculate resistance on thermistor
    R2 = R1 / ((1023.0 / (float)Vo) - 1.0);
    logR2 = log(R2);
    T = (1.0 / (c1 + c2*logR2 + c3*logR2*logR2*logR2)); // temperature in Kelvin
    T = T - 273.15; //convert Kelvin to Celcius
    // T = (T * 9.0)/ 5.0 + 32.0; //convert Celcius to Farenheit
    Serial.print(Vo);
    Serial.print("Temperature: "); 
    Serial.print(T);
    Serial.println(" C"); 
    delay(500);
    }

Phenomenon
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.. image:: /img/phenomenon/13.jpg