Monitoring Temperature with Arduino & Thermistor

How Easy Is It To Use a Thermistor With Arduino?

The thermistor is an essential tool for any avid tinkerer, but using one can sometimes be confusing. Many people wonder if it is easy to use a thermistor with Arduino. The answer is yes: thermistors are easy to use and it only requires a few steps to get started.

What is a Thermistor?

A thermistor is a temperature-sensing device that is used in many electronic applications. The device is made up of two types of materials that, when exposed to heat, produce different electrical resistance. This helps in sensing the temperature by measuring the resistance.

Choosing the Right Thermistor for Arduino

It is important to choose the right thermistor for your Arduino project. There are three main types of thermistor available: Negative Temperature Coefficient (NTC), Positive Temperature Coefficient (PTC), and Variable Resistor (VAR). Each type has its own advantages and disadvantages, so it is important to research which thermistor is best suited to your application.

Connecting the Thermistor to Arduino

Once you have decided on the type of thermistor you would like to use, it is time to connect it to your Arduino. The thermistor needs to be connected to two pins on the Arduino board. One pin should be connected to the 5V power supply, while the other should be connected to the Analog input. You then need to write a program that will read the value from the Analog input and convert it into a temperature reading.

Here is an example source code for using a thermistor with Arduino:

#define THERMISTOR_PIN A0
#define SERIES_RESISTOR 10000
#define THERMISTOR_NOMINAL 10000
#define TEMPERATURE_NOMINAL 25
#define B_COEFFICIENT 3950

void setup() {
  Serial.begin(9600); // initialize serial communication
}

void loop() {
  int sensorValue = analogRead(THERMISTOR_PIN); // read the value from the thermistor pin
  float resistance = SERIES_RESISTOR / ((1023.0 / sensorValue) - 1.0); // calculate the resistance of the thermistor
  float temperature = 1.0 / (1.0 / (TEMPERATURE_NOMINAL + 273.15) + (1.0 / B_COEFFICIENT) * log(resistance / THERMISTOR_NOMINAL)) - 273.15; // calculate the temperature in Celsius

  Serial.print("Resistance: ");
  Serial.print(resistance);
  Serial.print(" ohms - Temperature: ");
  Serial.print(temperature);
  Serial.println(" °C");

  delay(1000); // delay for one second before reading again
}

In this example, a thermistor is connected to analog pin A0 of the Arduino, with a series resistor of 10,000 ohms. The thermistor nominal resistance is also 10,000 ohms, the temperature nominal value is 25°C, and the B coefficient is 3950.

In the setup() function, serial communication is initialized at a baud rate of 9600.

In the loop() function, the analogRead() function is used to read the value from the thermistor pin. Then, the resistance of the thermistor is calculated using the formula for a voltage divider circuit. Next, the temperature in Celsius is calculated using the Steinhart-Hart equation, which takes into account the thermistor resistance, nominal resistance, nominal temperature, and B coefficient.

Finally, the resistance and temperature values are printed to the serial monitor using the Serial.print() function. The delay() function is used to wait for one second before reading the values again.

Benefits of Using Arduino

Using Arduino for thermistor projects has several advantages. Firstly, Arduino is relatively simple to learn and use, compared to more complex programming languages like C++. It also provides the flexibility to customize your project by adding additional components like sensors and displays. Finally, Arduino is compatible with many different operating systems, making it easy to develop code for different platforms.

Using a thermistor with Arduino is easy and can be a fun way to explore various temperature control projects. Whether you’re looking to control a robot or measure the temperature of your environment, Arduino makes it simple and relatively straightforward.