Copy of Binary Coil-Spring Clock

This Geogebra simulation demonstrates how a series of springs could theoretically be used to construct a "binary clock." Depending on the age/power/compatibility/coolness of your device, you may have better luck downloading this construction and running it from the GeoGebra program rather than within a web browser.
In relation to each spring, what is the significance of the digits below them? How may one read the passing of time from these digits? What physical constraints might hinder or prevent the function of such a clock in the "real world?" Can you think of how pendulums might be utilized instead of springs in the design of a binary clock? In what way(s) might pendulums work better in the real world? What additional physical constraints might one encounter with pendulums?