Calibrating Thermistors for the Arduino

This is my first post about my current geek project: building a wireless thermometer/alarm/data logger for my Weber smoker. Until now, I’ve been using a Maverick/RediCheck wireless unit which is merely OK. The wireless signal tends to be really flaky and it has only one temp probe. There are multi-probe units available, they’re still missing other features I’d be interested in such as logging the data for generating graphs, measuring ambient temperature outside and setting multiple alarms (for both the food and smoker temperature too high/low).

For my food and smoker temp measuring needs, I picked up 3 food safe probes from Thermoworks for $8/ea. Unfortunately, the probes come with no technical documentation and my email to the company requesting information was ignored. Contrary to my initial thoughts, these probes are not the same as those sold by Maverick or Amwei. I was however able to determine they are NTC thermistors and some searches turned up a way to convert the resistor readings into actual temperatures. Continue reading