Make: JavaScript Robotics

Chapter 7. An Indoor Sundial

By Lyza Gardner

It’s entirely absurd to design and construct an indoor sundial like the one shown in Figure 7-1, which is why it’s so fun to do so. We’ll craft our sundial as a tongue-in-cheek nod to the astronomical timepieces that have existed for millennia.

Unlike traditional sundials, which require a clear day and an outdoor location, we’ll use our own “sun” and position it as needed to tell, roughly, our own local solar time.

A horizontal-style sundial is typically disk shaped, constructed with a hand or pointer, called the gnomon, which is aligned to true north (or due south in the southern hemisphere). The gnomon rises away from the center of the disk at an angle equivalent to the local latitude. ...