MCP9808 is a highly accurate digital temperature sensor ±0.5°C I2C mini module. They are embodied with user- programmable registers that facilitate temperature sensing applications. The MCP9808 high-accuracy temperature sensor has become an industry standard in terms of form factor and intelligence, providing calibrated, linearised sensor signals in digital, I2C format.

In this tutorial the interfacing of the MCP9808 sensor module with arduino nano has been demonstrated . To read the temperature values, we have used raspberry pi with an I2c adapter.This I2C adapter makes the connection to the sensor module easy and more reliable.

Step 1: Hardware Required:

The materials that we need for accomplishing our goal includes the following hardware components:

1. MCP9808

2. Arduino Nano

3. I2C Cable

4. I2C Shield for Arduino nano

Step 2: Hardware Hookup:

The hardware hookup section basically explains the wiring connections required between the sensor and the arduino nano . Ensuring correct connections is the basic necessity while working on any system for the desired output. So, the requisite connections are as follows:

The MCP9808 will work over I2C . Here is the example wiring diagram, demonstrating how to wire up each interface of the sensor.

Out-of-the-box, the board is configured for an I2C interface, as such we recommend using this hookup if you’re otherwise agnostic. All you need is four wires!

Only four connections are required Vcc, Gnd, SCL and SDA pins and these are connected with the help of I2C cable.

These connections are demonstrated in the pictures above.

Step 3: Code for Temperature Measurement:

Let's start with the Arduino code now.

While using the sensor module with the Arduino, we include Wire.h library. "Wire" library contains the functions which facilitate the i2c communication between the sensor and the Arduino board.

The entire Arduino code is given below for the convenience of the user:

<p>#include<Wire.h></p><p>// MCP9808 I2C address is 0x18(24)</p><p>#define Addr 0x18</p><p>void setup()</p><p>{  </p><p>// Initialise I2C communication as MASTER  </p><p>Wire.begin();  </p><p>// Initialise Serial Communication, set baud rate = 9600  </p><p>Serial.begin(9600);    </p><p>// Start I2C Transmission  </p><p>Wire.beginTransmission(Addr);  </p><p>// Select configuration register  </p><p>Wire.write(0x01);  </p><p>// Continuous conversion mode, Power-up default  </p><p>Wire.write(0x00);  </p><p>Wire.write(0x00);  </p><p>// Stop I2C Transmission  </p><p>Wire.endTransmission();    </p><p>// Start I2C Transmission  </p><p>Wire.beginTransmission(Addr);  </p><p>// Select resolution register  </p><p>Wire.write(0x08);  </p><p>// Resolution = +0.0625 / C  </p><p>Wire.write(0x03);  </p><p>// Stop I2C Transmission  </p><p>Wire.endTransmission();</p><p>}
void loop()</p><p>{  </p><p>unsigned int data[2];    </p><p>// Starts I2C communication  </p><p>Wire.beginTransmission(Addr);  </p><p>// Select data register  </p><p>Wire.write(0x05);  </p><p>// Stop I2C transmission  </p><p>Wire.endTransmission();    </p><p>// Request 2 bytes of data  </p><p>Wire.requestFrom(Addr, 2);    </p><p>// Read 2 bytes of data  </p><p>// temp MSB, temp LSB  </p><p>if(Wire.available() == 2)  </p><p>{    </p><p>data[0] = Wire.read();    </p><p>data[1] = Wire.read();  </p><p>}    </p><p>// Convert the data to 13-bits  </p><p>int temp = ((data[0] & 0x1F) * 256 + data[1]);  </p><p>if(temp > 4095)  </p><p>{    </p><p>temp -= 8192;  </p><p>}  </p><p>float cTemp = temp * 0.0625;  </p><p>float fTemp = cTemp * 1.8 + 32;    </p><p>// Output data to screen  </p><p>Serial.print("Temperature in Celsius : ");  </p><p>Serial.println(cTemp);  </p><p>Serial.println(" C");  </p><p>Serial.print("Temperature in Fahrenheit : ");  </p><p>Serial.println(fTemp);  </p><p>Serial.println(" F");  </p><p>delay(500);</p><p>}</p>

In wire library Wire.write() and Wire.read() is used to write the commands and read the sensor output.

Serial.print() and Serial.println() is used to display the output of the sensor on the serial monitor of the Arduino IDE.

The output of the sensor is shown in the picture above.

Step 4: Applications:

MCP9808 Digital Temperature Sensor has several industry level applications which incorporate industrial freezers and refrigerators along with various food processors. This sensor can be employed for various personal computers, servers as well as other PC peripherals.