Thermocouple

Note: most K-Type thermocouples have about ±2°C to ±6°C accuracy

Thermocouples

• SF K-Type 200 mm long SS probe 0 to 400°C
• Type K Glass Braid Thermocouple
• Type-K Glass Braid Insulated Stainless Steel Tip

AF thermocouple tutorial

 

Custom Option

   

Custom FeatherWing that accepts the mounting of either a Adafruit K-Type Thermocouple AD8495 Breakout, or a Adafruit MAX31856 Universal Thermocouple Amplifier This board allows you to connect a Type K thermocouple to the AD8495 Breakout and output to an analog input, or connect a Type K, J, N, R, S, T, E, or B type thermocouple to the MAX31856 Universal breakout and output to 4-wire SPI.  

 

Adafruit K-Type Thermocouple AD8495 Breakout

Adafruit K-Type Thermocouple AD8495 Breakout $12/ea.   Sensing Accuracy Range: ± 1°C around room temperature, ± 2°C for −25°C to +400°C.   Requires at lease one analog pin.   AF tutorial

 

Adafruit MAX31856 Universal Thermocouple Amplifier

Adafruit Universal Thermocouple Amplifier MAX31856 Breakout -210°C to +1800°C; $17.50/ea; SPI data output to any 4 digital I/O pins.   AF tutorial

 

Feather M0 Code

			/*
			  Adafruit MAX31856 Universal Thermocouple Amplifier
			  Product #3263

			  
			*/

			// M0  (Feather M0)
			// Make sure Arduino IDE board = "Adafruit Feather M0"

			//////////////////////////////////////////////////////////////////////////////
			// 300000 ms = 5 min
			// 60000 ms = 1 min
			// 10000 ms = 10 sec = 0.1 Hz 
			// 1000 ms = 1 sec = 1 Hz
			// 100 ms = 0.1 sec = 10 Hz
			// 10 ms = 0.01 sec = 100 Hz
			const unsigned long timerInterval = 1000;  
			unsigned long timerLast = 0;  // timer
			//////////////////////////////////////////////////////////////////////////////


			//////////////////////////////////////////////////////////////////////////////
			// Adafruit MAX31856 Universal Thermocouple Amplifier
			// Library: Adafruit_MAX31856   https://github.com/adafruit/Adafruit_MAX31856
			#include 
			// Adafruit_MAX31856(CS, MOSI/SDI, MISO/SDO, SCK)
			// Below for Feather M0 Basic
			//Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(A1, 23, 22, 24);
			//Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(A1);
			Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(A1, A4, A2, A5);
			// Below works on Arduino Uno  (must connect all wires)
			//Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(10, 11, 12, 13);
			//Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(10); // 11, 12, 13 hardware SPI
			//Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(4, 5, 6, 7);
			// Particle Argon/Boron:
			//Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(A1, D3, D4, D2);
			//////////////////////////////////////////////////////////////////////////////


			void setup() {  
			  Serial.begin(9600);
			  while (!Serial) {
				delay(1);
			  }

			  //////////////////////////////////////////////////////////////////////////////
			  // Adafruit MAX31856 Universal Thermocouple Amplifier
			  while (! Thermocouple.begin()) {
				delay(1);
			  }  
			  Thermocouple.setThermocoupleType(MAX31856_TCTYPE_K);
			  //////////////////////////////////////////////////////////////////////////////
			  
			  
			  Serial.println("Setup complete\n");
			} // setup()


			void loop() {

				
			  if (timerLast > millis())  timerLast = millis();
			  if ((millis() - timerLast) > timerInterval) {
				// Check and print any thermocouple faults
				uint8_t fault = Thermocouple.readFault();
				if (fault) {
				  if (fault & MAX31856_FAULT_CJRANGE) Serial.println("Cold Junction Range Fault");
				  if (fault & MAX31856_FAULT_TCRANGE) Serial.println("Thermocouple Range Fault");
				  if (fault & MAX31856_FAULT_CJHIGH)  Serial.println("Cold Junction High Fault");
				  if (fault & MAX31856_FAULT_CJLOW)   Serial.println("Cold Junction Low Fault");
				  if (fault & MAX31856_FAULT_TCHIGH)  Serial.println("Thermocouple High Fault");
				  if (fault & MAX31856_FAULT_TCLOW)   Serial.println("Thermocouple Low Fault");
				  if (fault & MAX31856_FAULT_OVUV)    Serial.println("Over/Under Voltage Fault");
				  if (fault & MAX31856_FAULT_OPEN)    Serial.println("Thermocouple Open Fault");
				  Serial.println(" ");
				} else {
				  // NOTE:  You can still have a wiring fault that is not detected, and
				  //        the temperature will be reported as 0.00
				  Serial.print("Thermocouple Temp: "); 
				  Serial.print(Thermocouple.readThermocoupleTemperature());
				  Serial.println(" C");     
				}
				timerLast = millis();
			  }
			  
			  // The yield() function allows ESP8266 microcontroller to run a 
			  // number of utility functions in the background, without causing 
			  // the ESP8266 to crash or reset. Include it within any 
			  // while() + digitalRead() and other loops;
			  yield();
			  
			} // loop()

			

 

Argon / Boron Code

			/*
				particle.io Argon
				device name: Argon_A
			 */

			// Create a timer executed every 25 seconds.
			const unsigned long timerA = 25000;  // 25000 ms = 25 seconds
			unsigned long timerAlap = millis();  // timer


			//////////////////////////////////////////////////////////////////////////////
			// Adafruit MAX31856 Universal Thermocouple Amplifier
			// Library: Adafruit_MAX31856   https://github.com/adafruit/Adafruit_MAX31856
			#include 
			// Adafruit_MAX31856(CS, MOSI/SDI, MISO/SDO, SCK)
			Adafruit_MAX31856 Thermocouple = Adafruit_MAX31856(A1, D3, D4, D2);
			double tempC = 0.0;
			//////////////////////////////////////////////////////////////////////////////

			int pinLEDWhite = A0; // A0 = D19


			void setup() {
			  pinMode(pinLEDWhite, OUTPUT);

			  //////////////////////////////////////////////////////////////////////////////
			  // Adafruit MAX31856 Universal Thermocouple Amplifier
			  while (! Thermocouple.begin()) {
				digitalWrite(pinLEDWhite, HIGH);
				delay(1);
				digitalWrite(pinLEDWhite, LOW);
			  }
			  Thermocouple.setThermocoupleType(MAX31856_TCTYPE_K);
			  //////////////////////////////////////////////////////////////////////////////

			  // Publish the value of tempC as a Particle variable.
			  // The frequency of publishing is managed by Particle. 
			  Particle.variable("tempC",tempC);

			  blinkLED(pinLEDWhite);
			  timerAlap = millis(); // reset the timer
			}   // setup()

			void loop() {
			  
			  if (timerAlap > millis())  timerAlap = millis(); 
			  if (millis() - timerAlap > timerA) {  
				 uint8_t fault = Thermocouple.readFault();
				if (fault) {
				  digitalWrite(pinLEDWhite, HIGH);
				} else {
				  tempC = Thermocouple.readThermocoupleTemperature();
				}
				
				blinkLED(pinLEDWhite);
				timerAlap = millis(); // reset the timer
			  }


			}   // loop()


			void blinkLED(byte ledPIN){
			  //  consumes 300 ms.
			  for(int i = 5; i>0; i--){
				digitalWrite(ledPIN, HIGH);
				delay(30);
				digitalWrite(ledPIN, LOW);
				delay(30);
			  }    
			} // blinkLED()

			

 

K-Type Thermocouple - Grove Option

-50 to 600°C, and the accuracy is ±(2.0% + 2°C).   Operating range -40 to +125 °C.  

Grove K-Type Thermocouple details from Seeed

Interface the Grove sensor with the Particle IoT device using either the Grove Shield FeatherWing - Wio Lite or the Grove Shield FeatherWing.  

 

 

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Projects

FeatherWing