Overview

Thermocouples are very sensitive, requiring a good amplifier with a cold-compensation reference. The Adafruit MCP9600 does all that for you, and can be easily interfaced with any microcontroller or single-board-computer with I2C. Inside, the chip handles all the analog stuff for you, and can interface with just about any thermocouple type: K, J, T, N, S, E, B and R type are all supported! You can also set various alerts for over/under temperature, and read the thermocouple (hot) temperature and the chip (cold) temperature. All this over common I2C.

This breakout board has the chip itself, a 3.3V regulator and level shifting circuitry, all assembled and tested. Works great with 3.3V or 5V logic. Comes with a 2 pin terminal block (for connecting to the thermocouple) and pin header (to plug into any breadboard or perfboard).

The Adafruit MCP9600 features:

  • Works with any K, J, T, N, S, E, B and R type thermocouple
  • Datasheet rated for:
    K Type: -200°C to +1372°C
    J Type: -150°C to +1200°C
    T Type: -200°C to +400°C
    N Type: -150°C to +1300°C
    E Type: -200°C to +1000°C
    S Type: +250°C to +1664°C
    B Type: +1000°C to +1800°C
    R Type: +250°C to +1664°C
  • Resolution of ±0.0625 °C - note that K thermocouples have about ±2°C to ±6°C accuracy
  • Internal temperature reading
  • 3.3 to 5v power supply and logic level compliant
  • I2C data connection
adafruit_products_MCP9600_Top_Headers.jpg
The board comes with a terminal block and header if you would like to solder them on (or not).

Pinouts

Power Pins

  • Vin - this is the power pin. Since the sensor chip uses 3 VDC, we have included a voltage regulator on board that will take 3-5VDC and safely convert it down. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V micro like Arduino, use 5V
  • 3Vo - this is the 3.3V output from the voltage regulator, you can grab up to 100mA from this if you like
  • GND - common ground for power and logic

I2C Logic Pins

  • SCL - this is the I2C clock pin, connect to your microcontroller's I2C clock line.
  • SDA - this is the I2C data pin, connect to your microcontroller's I2C data line.

Alert Pins

  • A1 - A4 - Alert 1 - Alert 4 output pins

Address Pin

  • ADR - Allows for setting I2C address

Arduino

Wiring

Connecting the MCP9600 to your Feather or Arduino is easy:

  • If you are running a Feather (3.3V), connect Feather 3V to board VIN
  • If you are running a 5V Arduino (Uno, etc.), connect Arduino 5V to board VIN
  • Connect Feather or Arduino GND to board GND
  • Connect Feather or Arduino SCL to board SCL
  • Connect Feather or Arduino SDA to board SDA
  • Connect thermocouple + to board screw terminal +
  • Connect thermocouple - to board screw terminal -

The final results should resemble the illustration above, showing an Adafruit Metro development board.

The MCP9600 will return a temperature for the hot junction even if there is no thermocouple connected. There will not be an error!

Installation

You can install the Adafruit MCP9600 Library for Arduino using the Library Manager in the Arduino IDE:

Click the Manage Libraries ... menu item, search for Adafruit MCP9600, and select the Adafruit MCP9600 library:

Also get the Adafruit BusIO library

Load Example

Open up File -> Examples -> Adafruit MCP9600 -> mcp9600_test and upload to your Arduino wired up to the sensor.

Upload the sketch to your board and open up the Serial Monitor (Tools->Serial Monitor). You should see the the values for hot junction, cold junction and ADC.

Example Code

The following example code is part of the standard library, but illustrates how you can retrieve sensor data from the MCP9600 for the hot junction, cold junction and ADC values:

#include <Wire.h>
#include <Adafruit_I2CDevice.h>
#include <Adafruit_I2CRegister.h>
#include "Adafruit_MCP9600.h"

#define I2C_ADDRESS (0x67)

Adafruit_MCP9600 mcp;
Adafruit_I2CDevice i2c_dev = Adafruit_I2CDevice(I2C_ADDRESS);

void setup()
{
    Serial.begin(115200);
    while (!Serial) {
      delay(10);
    }
    Serial.println("MCP9600 HW test");

    /* Initialise the driver with I2C_ADDRESS and the default I2C bus. */
    if (! mcp.begin()) {
        Serial.println("Sensor not found. Check wiring!");
        while (1);
    }

  Serial.println("Found MCP9600!");

  mcp.setADCresolution(MCP9600_ADCRESOLUTION_18);
  Serial.print("ADC resolution set to ");
  switch (mcp.getADCresolution()) {
    case MCP9600_ADCRESOLUTION_18:   Serial.print("18"); break;
    case MCP9600_ADCRESOLUTION_16:   Serial.print("16"); break;
    case MCP9600_ADCRESOLUTION_14:   Serial.print("14"); break;
    case MCP9600_ADCRESOLUTION_12:   Serial.print("12"); break;
  }
  Serial.println(" bits");

  mcp.setThermocoupleType(MCP9600_TYPE_K);
  Serial.print("Thermocouple type set to ");
  switch (mcp.getThermocoupleType()) {
    case MCP9600_TYPE_K:  Serial.print("K"); break;
    case MCP9600_TYPE_J:  Serial.print("J"); break;
    case MCP9600_TYPE_T:  Serial.print("T"); break;
    case MCP9600_TYPE_N:  Serial.print("N"); break;
    case MCP9600_TYPE_S:  Serial.print("S"); break;
    case MCP9600_TYPE_E:  Serial.print("E"); break;
    case MCP9600_TYPE_B:  Serial.print("B"); break;
    case MCP9600_TYPE_R:  Serial.print("R"); break;
  }
  Serial.println(" type");

  mcp.setFilterCoefficient(3);
  Serial.print("Filter coefficient value set to: ");
  Serial.println(mcp.getFilterCoefficient());

  mcp.setAlertTemperature(1, 30);
  Serial.print("Alert #1 temperature set to ");
  Serial.println(mcp.getAlertTemperature(1));
  mcp.configureAlert(1, true, true);  // alert 1 enabled, rising temp

  mcp.enable(true);

  Serial.println(F("------------------------------"));
}

void loop()
{
  Serial.print("Hot Junction: "); Serial.println(mcp.readThermocouple());
  Serial.print("Cold Junction: "); Serial.println(mcp.readAmbient());
  Serial.print("ADC: "); Serial.print(mcp.readADC() * 2); Serial.println(" uV");
  delay(1000);
}

You should get something resembling the following output when you open the Serial Monitor at 9600 baud:

Downloads

This guide was first published on Jun 12, 2019. It was last updated on Jun 12, 2019.