Wemos and Max6675 example

In this example we take a look at the MAX6675 Cold-Junction-Compensated K-Thermocouple-to-Digital Converter

The MAX6675 performs cold-junction compensation and digitizes the signal from a type-K thermocouple. The data is output in a 12-bit resolution, SPI™-compatible, read-only format.
This converter resolves temperatures to 0.25°C, allows readings as high as +1024°C, and exhibits thermocouple accuracy of 8 LSBs for temperatures ranging from 0°C to +700°C.

Key Features

Cold-Junction Compensation
Simple SPI-Compatible Serial Interface
12-Bit, 0.25°C Resolution
Open Thermocouple Detection

Usually you use these in a breakout/module form and can also purchase a kit which includes a thermocouple. Here is a picture of the module that I purchased

MAX6675_module

Here are the connections , sometimes these are named differently on the modules, in particular the CS connection

Vcc connected to 3.3v
Gnd connected to Gnd
SO connected to Pin 6
SS/CS connected to Pin 7
CSK connected to Pin 8

Code

You will need the MAX6675 library – https://github.com/adafruit/MAX6675-library

#include "Max6675.h"
 
Max6675 ts(D6, D7, D8);
// Max6675 module: SO on pin D6, SS on pin D7, CSK on pin D8 of Wemos Mini
 
void setup()
{
 ts.setOffset(0);
 // set offset for temperature measurement.
 Serial.begin(9600);
}
 
void loop()
{
 Serial.print(ts.getCelsius(), 2);
 Serial.print(" C / ");
 Serial.print(ts.getFahrenheit(), 2);
 Serial.print(" F / ");
 Serial.print(ts.getKelvin(), 2);
 Serial.print(" Kn");
 Serial.println();
 delay(2000);
}

Results

Open the serial monitor window and you should see something like this

24.00 C / 75.20 F / 259.15 Kn
24.00 C / 75.20 F / 259.15 Kn
25.50 C / 77.90 F / 260.65 Kn
26.75 C / 80.15 F / 261.90 Kn
27.50 C / 81.50 F / 262.65 Kn
27.25 C / 81.05 F / 262.40 Kn

 

Links

You can pick up the module and a thermocouple for about $4

MAX6675 Module + K Type Thermocouple Thermocouple Sensor

3 COMMENTS

  1. C:\Users\Tslod\Documents\Arduino\libraries\MAX6675-library-master\max6675.cpp:9:24: fatal error: util/delay.h: No such file or directory

    #include

    ^

    compilation terminated.

    exit status 1
    Błąd kompilacji dla płytki WeMos D1 R1.

    Can you help me?

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