I am using a MAX31855 to measure a thermocouple (TC). In my system I also have an LED array (18 LEDs) and some stepper motors.
Normally the TC reads 23C (my room). As soon as I switch on the LEDs, it shows 50C - WTF? :o If I move the steppers, the TC goes haywire, jumping between 0 - 200C and also giving errors on some readings.
I tried adding lots of caps, made a low-pass filter to power the MAX31855, etc. Nothing works. I'm out of ideas.
The MAX31855 is powered by the Arduino MEGA 5V line (from USB) while the rest of the components are off a LM7806 6V regulator which is getting juice from a power supply (~10V in).
Who has some ideas?