Introduction: Temperature Measurement Using MCP9803 and Particle Photon

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MCP9803 is a 2-wire high accuracy temperature sensor. They are embodied with user- programmable registers that facilitate temperature sensing applications. This sensor is suited for highly sophisticated multi-zone temperature monitoring system.

In this tutorial the interfacing of the MCP9803 sensor module with particle photon has been illustrated. To read the temperature values, we have used particle 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. MCP9803

2. Particle Photon

3. I2C Cable

4. I2C Shield for particle photon

Step 2: Hardware Hookup:

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

The MCP9803 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:

Lets start with the particle code now.

While using the sensor module with the particle, we include application.h and spark_wiring_i2c.h library. "application.h" and spark_wiring_i2c.h library contains the functions which facilitate the i2c communication between the sensor and the particle.

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

<p>#include<application.h> </p><p>#include<spark_wiring_i2c.h> </p><p>// MCP9803 I2C address is 0x48(72)</p><p>#define Addr 0x48</p><p>float cTemp = 0, fTemp = 0;</p><p>void setup()</p><p>{    </p><p>// Set variable    </p><p>Particle.variable("i2cdevice", "MCP9803");    </p><p>Particle.variable("cTemp", cTemp);        </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(0x60);    </p><p>// Stop I2C Transmission    </p><p>Wire.endTransmission();    </p><p>delay(300);</p><p>}</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(0x00);    </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] =;        </p><p>data[1] =;    </p><p>}        </p><p>// Convert the data to 12-bits    </p><p>int temp = ((data[0] * 256) + data[1]) / 16.0;    </p><p>if(temp > 2047)    </p><p>{        </p><p>temp -= 4096;    </p><p>}    </p><p>cTemp = temp * 0.0625;    </p><p>fTemp = cTemp * 1.8 + 32;      </p><p>// Output data to serial monitor    </p><p>Particle.publish("Temperature in Celsius : ", String(cTemp));    </p><p>Particle.publish("Temperature in Fahrenheit : ", String(fTemp));    </p><p>delay(500);</p><p>}</p>

Particle.variable() function creates the variables to store the output of the sensor and Particle.publish() function displays the output on the dashboard of the site.

The sensor output is shown in the picture above for your reference.

Step 4: Applications:

MCP9803 can be employed in a wide arena of devices which include personal computer and peripherals, hard disk drives, various entertainment systems, office systems and data communication systems. This sensor can be incorporated in various sophisticated systems.