A Differential Scanning Calorimeter Using a Cellphone and GUI-O User Interface

In this month’s article, Brian describes how he built his latest version of a Differential Scanning Calorimeter—the first version of which he designed 20 years ago.

- By Brian Millier

In this article I'll be describing the most recent version of a Differential Scanning Calorimeter (DSC) that I originally designed for use in university Material Science teaching labs. I have built many of these units over the last 20 years, though this latest version differs from past units in that it uses a cellphone as the user interface. All previous versions were connected to, and controlled by, a PC.

The following summary, which describes a basic DSC instrument, is part of a conference presentation titled “Teaching Materials Science in the Lab: Learning Stuff from the Ground Up,” which I co-authored with Gianna Alemán-Milán, PhD, and Mary Anne White, PhD, and can be found on the Circuit Cellar Article Materials and Resources webpage [1].

A DSC measures the power necessary to establish a nearly zero temperature difference between a substance and a reference material as the two specimens are subjected to a temperature scan over a region of interest. This involves heating (and, optionally, may involve cooling), at a user-selected temperature scan rate. Throughout the scan, the temperatures of the sample and reference are kept the same by varying the power supplied to each of the sample and reference heaters. The energy required to do this is a measure of the enthalpy, or heat capacity changes, in the sample relative to the reference.