Understanding the NTC Sensor
Before we delve into the exciting process of interfacing the NTC sensor with an Arduino Uno, let's take a moment to understand what an NTC sensor is and how it works. NTC sensors are widely used for temperature measurement due to their varying resistance with temperature changes. As the temperature increases, the resistance of the NTC sensor decreases, and vice versa. This unique characteristic makes NTC sensors invaluable for creating accurate temperature measurement systems.How NTC Sensors Work
NTC sensors are made of semiconducting materials that exhibit the NTC effect. This effect causes the sensor's resistance to decrease as temperature rises. The relationship between resistance and temperature follows a well-defined curve, usually provided by the sensor manufacturer. This curve helps us convert the resistance values into corresponding temperature readings.Components You'll Need
Before we dive into the nitty-gritty of connecting the NTC sensor to the Arduino Uno, let's gather the components you'll need for this project: Arduino Uno Board NTC Sensor (Type: Specify the type you're using, e.g., 10K ohms NTC) Resistor (10K ohms) Breadboard and Jumper Wires.Choosing the Right NTC Sensor
When selecting an NTC sensor for your project, it's crucial to consider its resistance at room temperature and the range of temperatures you intend to measure. Different NTC sensors have varying resistance values at a given temperature, so ensure that the sensor's characteristics align with your project requirements.Interfacing the NTC Sensor with Arduino Uno
Now, let's roll up our sleeves and get into the heart of the project – interfacing the NTC sensor with the Arduino Uno.Step 1: Circuit Setup
Begin by placing your Arduino Uno on the breadboard. Connect the 5V pin of the Arduino to the positive rail on the breadboard and the GND pin to the negative rail. Next, connect one leg of the NTC sensor to the 5V rail and the other leg to the negative rail through a 10K ohms resistor. This forms a voltage divider circuit, allowing us to measure the voltage drop across the NTC sensor.Step 2: Analog Pin Connection
Choose an analog input pin on the Arduino Uno – let's say A0. Connect one end of a jumper wire to the junction between the NTC sensor and the resistor, and connect the other end to the chosen analog pin (A0). This connection will allow us to measure the analog voltage across the voltage divider.Coding the Arduino
With the hardware connections in place, it's time to write the Arduino code to read and convert the analog voltage into a temperature value.
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cpp
#define ntc_pin A0 // Pin,to which the voltage divider is connected#define nominal_resistance 10000 //Nominal resistance at 25⁰C#define nominal_temeprature 25 // temperature for nominal resistance (almost always 25⁰ C)#define samplingrate 5 // Number of samples#define beta 3950 // The beta coefficient#define Rref 10000 //Value of resistor used for the voltage dividerint samples = 0; //array to store the samples void setup(void) { Serial.begin(9600); //initialize serial communication at a baud rate of 9600} void loop(void) { uint8_t i; float average; samples = 0; // take voltage readings from the voltage divider for (i = 0; i < samplingrate; i++) { samples += analogRead(ntc_pin); delay(10); } average = 0; average = samples / samplingrate; Serial.println("\n \n"); Serial.print("ADC readings "); Serial.println(average); // Calculate NTC resistance average = 1023 / average - 1; average = Rref / average; Serial.print("Thermistor resistance "); Serial.println(average); float temperature; temperature = average / nominal_resistance; // (R/Ro) temperature = log(temperature); // ln(R/Ro) temperature /= beta; // 1/B * ln(R/Ro) temperature += 1.0 / (nominal_temeprature + 273.15); // + (1/To) temperature = 1.0 / temperature; // Invert temperature -= 273.15; // convert absolute temp to C Serial.print("Temperature "); Serial.print(temperature); Serial.println(" *C"); delay(2000); }
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