Interfacing a Thermocouple with Arduino platform can be easily done by integrating a MAX31855 to your project. This IC is a Cold-Junction Compensated Analog to Digital Converter amplifier especially design for use with a Thermocouple. The converter provides 14-Bit of digitized temperature data with 0.25°C resolution and can be used with most of common Thermocouple types. MAX31855 module sends serial data to Arduino by SPI protocol. 3 I/O are required to establish the interface: data out, chip select and clock. The temperature readings are shown on the 4 Digit 7-Segment LED display with integrated TM1637 chip. LED module also uses a serial interface for communication with Arduino. I’ve published a number of projects based on this popular chip. Here is link to a 3 Digit LED counter based on TM1637. Now back to a Thermocouple design. Next the design schematic is shown.
Arduino sketch for present circuit can be downloaded at this link. The current setup was tested with K-Type thermocouple taken from a multimeter kit. It seems to operate as expected and shows a correct temperature value. I only have one thermocouple so I can not perform any extensive testing. Here is the prototype board I’ve used to test this design.
