Amplifier In this project, you'll learn how to use a K-Type Thermocouple, a MAX6675 amplifier, and an ESP8266 NodeMCU board to read temperature. A K-type thermocouple is a type of temperature sensor that can measure temperatures from 200 to 1260oC (326 to 2300oF).

A thermocouple is a tool for figuring out how hot or cold something is. It is made up of two different metal wires that are joined together to make a junction. When the junction is heated or cooled, a small voltage is created in the thermocouple's electrical circuit. This voltage can be measured, and it shows how hot or cold the junction is. Thermocouples are used in everything from home appliances to industrial processes to making electric power to monitoring and controlling furnaces to making food and drinks to sensors in cars and aeroplane engines to rockets, satellites, and spacecraft. What is a thermocouple K-type? A thermocouple is a device made up of two different electrical wires that meet at an electrical junction called a "thermal junction." The temperature change at the junction causes a small but measurable change in voltage at the reference junction, which can be used to figure out the temperature. Different metals can be used to make a thermocouple. The voltage range, cost, and sensitivity will all depend on the metals that are used. The different types of thermocouples are B, E, J, N, K, R, T, and S. These letters stand for the standard metal combinations that make up each type.

The k-type thermocouple is the subject of our lesson. A k-type thermocouple has conductors made of chrome and alumel, and its temperature range is usually from 200 to 1260oC (328 to 2300oF). Amplifier MAX6675 We need a thermocouple amplifier to get the temperature from the thermocouple. The temperature that comes out of the thermocouple amplifier depends on the voltage read at the reference junction. The difference in temperature between the reference junction and the thermal junction affects the voltage at the reference junction. So, we need to know how hot or cold the reference junction is. The MAX6675 thermocouple comes with a temperature sensor that measures the temperature at the reference junction (cold-compensation reference) and amplifies the small voltage at the reference junction so that we can read it with our microcontrollers. The MAX6675 amplifier talks to a microcontroller using the SPI protocol, and the data is sent out at a resolution of 12 bits. Schematic of ESP8266 with K-type thermocouple and MAX6675 amplifier

Most of the time, you can get a k-type thermocouple and a MAX6675 amplifier in the same package. Here is a list of the most important features of the MAX6675. Please look at the MAX6675 datasheet for a more in- depth explanation. Direct digital conversion of k-type thermocouple output Cold-junction compensation Simple SPI-compatible serial interface Operating voltage range: 3.0 to 5.5V -20oC to 85oC is the range of operating temperatures. Temperatures can be read up to 1024oC (1875oF) and are accurate to 0.25oC. K-Type Thermocouple Interface with MAX6675 Amplifier. As we've already talked about, the MAX6675 talks to a microcontroller using the SPI protocol.

K-type thermocouple amplifier MAX6675 ESP8266 NodeMCU (read Best ESP8266 development boards) Switcheroos (female-to-female) Installing MAX6675 Arduino Library There are different libraries that can be used with the MAX6675 amplifier to get the temperature from a K-type thermocouple. We'll use Adafruit's max6675 library. To add the library to your Arduino IDE, do the following: Open the Arduino IDE and go to Sketch > Include Library > Manage Libraries . It should open the Library Manager. Look for " max6675 " in the search box and download the Adafruit library.

You need to put the code on your ESP8266 board. Don't forget to choose the board you're using in Tools > Board and the COM port your board is

connected to in Tools > Port. After putting the code on the ESP8266, open the Serial Monitor and set the baud rate to 9600. Press the RST button on the ESP8266. Every second, the Serial Monitor shows a new temperature reading.