In-Depth: Interfacing MAX6675 Thermocouple Module with Arduino

This project measures high temperatures by interfacing a Type-K thermocouple probe with an Arduino Uno via a MAX6675 breakout module. A thermocouple generates a very small, non-linear voltage differential based on the temperature difference between its hot measuring junction and its cold reference junction. Because this voltage output is on the millivolt scale and requires precise cold-junction compensation to yield accurate absolute readings, the MAX6675 module handles this heavy lifting. The MAX6675 integrates a built-in amplifier, an analog-to-digital converter (ADC), and a digital compensation circuit specifically tailored for Type-K thermocouples. It reads the raw analog output from the probe, digitizes it into a 12-bit resolution format, and communicates the temperature data to the Arduino Uno. Through the software interface using the Adafruit MAX6675 Library, the Arduino utilizes a synchronous Serial Peripheral Interface (SPI)-like protocol to request and receive the digital temperature data over designated digital pins via jumper wires. Once the Arduino reads this digital word, it processes the data into readable temperature units (Celsius or Fahrenheit) for display, logging, or control applications, enabling reliable thermometry in environments far exceeding the limits of standard semiconductor sensors like the TMP36 or DHT22.