  To demystify the Digital Twin concept, we built a simple yet representative
thermal incubator system. The incubator is an insulated box fitted with a
heatbed, and complete with a software system for communication, a controller,
and simulation models. We developed two simulation models to predict the
temperature inside the incubator, one with two free parameters and one with
four free parameters. Our experiments showed that the latter model was better
at predicting the thermal inertia of the heatbed itself, which makes it more
appropriate for further development of the digital twin. The hardware and
software used in this case study are available open source, providing an
accessible platform for those who want to develop and verify their own
techniques for digital twins.
