A practical method for calibrating NTC thermistors

A project log for The Cave Pearl Project

Creating a generic data logging platform that is easy to build & modify for many different environmental monitoring projects.

ed-mallonEd Mallon 04/22/2024 at 00:580 Comments

Much of the existing information on sensor calibration assumes a certain level of pre-existing equipment/capability. This creates a chicken & egg problem with white-paper procedures targeting an accuracy that can not be obtained unless all the supporting parts of the system meet or exceed that same specification. This is almost never the case in educational contexts where STEM instructors often pay for classroom materials out of pocket. This mismatch parallels the situation twenty years ago when audiophiles dismissed the early MP3 players because they sounded so crude, completely missing the point that regular people were using them while jogging through downtown traffic. They were a good enough solution to a problem that didn’t need anything better. 

From the beginning our project has been developing DIY logger solutions with that kind of 80/20 point in mind, and this thermistor calibration procedure hits that mark:

To my knowledge this is the first time anyone has used the water freezing process to calibrate thermistors, rather than the melting point of an ice slurry.