Hi All!
I'm playing with K-typr thermocouple (TC) and MAX6675 module. Hooked it up to Arduino Uno and loaded this example:
// this example is public domain. enjoy!
// www.ladyada.net/learn/sensors/thermocouple
#include "max6675.h"
int thermoDO = 5;
int thermoCS = 4;
int thermoCLK = 3;
MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);
//int vccPin = 3;
//int gndPin = 2;
void setup() {
Serial.begin(9600);
// use Arduino pins
// pinMode(vccPin, OUTPUT); digitalWrite(vccPin, HIGH);
// pinMode(gndPin, OUTPUT); digitalWrite(gndPin, LOW);
Serial.println("MAX6675 test");
// wait for MAX chip to stabilize
delay(500);
}
void loop() {
// basic readout test, just print the current temp
// Serial.print("C = ");
Serial.println(thermocouple.readCelsius());
// Serial.print("F = ");
// Serial.println(thermocouple.readFahrenheit());
delay(250);
}
MAX is reading the TC, Uno is reading MAX and sending temperature readings to serial monitor in Arduino IDE.
BUT THERE IS SOMETHING WRONG!
Is says there is 25 deg C in my room! This is not true for sure so i hooked this TC to my Fluke multimeter (it has K-type TC input) and it says 19,4 deg C. I've checked analog thermometer - Fluke reading is ok.
So why do i get so wrong readings from MAX6675?
I have 5 MAX6675 modules and 10 TCs. Tried different modules w/ different TCs - same thing so i think the problem may be in the code!?
Please help me to sort it out.
I found this vid:
The guy (i don't know what is he talking about though - german...) did the same thing as I and got ca. 28 eg C reading as room ambinet temp. It looks too much as well.