btreichel wrote:That sounds like a scaling issue. A 2 point calibration would fix that. P.s. don't know if that is supported, etc. But simpliest 2 point is an ice bath, and boiling water.

Great idea! What is the appropriate way to do an ice bath?

Here's a description from Thermaworks on how to create a proper ice bath:
http://www.thermoworks.com/thermapen101 ... an_icebath

Thank You Susan!

Stryofoam cup, ground ice, water. Simple. For the hot side I set my Bonavita pot to 210, 211. If your not a sea level, no 212 for you.

I think i have a bad TC4 board as the temperature readings on the TC4 behave weird, the readings change even though the temperature stays constant. I ordered a phidget to double check the second output from the probes and if they look good, then I'll have to hunt for another TC4 or a TC4C if possible.

You could just switch it all to an arduino, with 3 1-wire TC's for about the same price. Thats if my memory of the price of a phidget is correct. (uno ~ 30, 3 1-wires 45).

Make sure your cell phone is no where near the unit. Mine was causing flucation in my Hottop K style.

That's a good point. I think I will remove the Bluetooth module i attached to the Arduino board and use a a usb cable.

I removed the Bluetooth module from the TC4 board and the power supply from the Arduino board. I attached the USB cable to the Arduino board and read the temps via Artisan. The temps were very stable, but as soon as I attached the power supply to the Arduino board, the temp readings came back garbage. It appears that the board works correctly if only the USB cable is attached, without the power supply.
When I had the HC-06 attached I noticed that I could change the baud rate and still get a reading via Artisan, that was strange. My next experiment is to remove the USB cable, re-attach the HC-06 bluetooth module, but use a voltage divider for the RX pin and see if the temp readings come back correctly.

Sounds like a grounding issue.