Tinkering with Time

Protocols and Programming Many embedded systems need to make use of synchronized time information. In this article, Jeff explores the history of time measurement and how it has led to NTP and other modern technologies for coordinating universal date and time. Using Arduino and the Espressif System’s ESP32, Jeff then goes through the steps needed to enable an embedded system to request, retrieve and display the synchronized date and time to a display. It’s been said that ”If you are on time, you’re late,” or, “To be early is to be on time.” It’s all relative. If you go to a meeting and people are already there, you feel as if you are late. If you are the first to arrive, you wonder if you’ve got the schedule wrong, and then you check your watch or phone for the time. Time can be troublesome for us, because the present is an ever-changing instant where the past meets the future. We cruise through life when all players reference the same moment, but should we become out of sync, the ride gets bumpy. We can imagine that in humanity’s early times the first concepts of time were cyclic periods—like day/night, seasons and life/death. Our fundamental measurement of a day directly relates to our life and history, and seems to tie all nature together. But what about those activities that occur within the confines of each day? Some way of defining the parts of a day were needed. At the time, we had one division—day/night—with most considering the start of a day to be daybreak or sunrise, and the start of night to be sunset. Since daytime was directly related to the sun’s position, the day could be divided into two parts based on whether the sun was rising in the sky or falling back toward the horizon. Observing the sun’s shadow gave way to the first sundials, which provided a visual indication of time relative to sunrise and sunset without physical divisions. One such division of the day was religious in origin: canonical hours or peri