People are obsessed with the time and the weather. We’ve talked about the weather since we were all cave dwellers hunting with spears. But the time is a different matter. Sure, people always had the idea of the passage of time. The sun rising and setting gives a natural sense of days, but daylight and dark periods vary by the time of year and to get an accurate and linear representation of time turns out to be rather difficult. That is unless you are a Greek engineer living in Alexandria around 250 BC.
Legend has it that and engineer working in his father’s barbershop led him to discover not only the first working clock, but also the pipe organ, launching the field of pneumatics in the process. That engineer was named Ctesibius and while his story is mostly forgotten, it shows he has a place as a historical hacker.
You might think there were timekeeping devices before 250 BC, and that’s sort of true. However, the devices before Ctesibius had many limitations. For example, a sundial can tell time, but only if the sun is shining. At night or during a storm it is worthless.
The funny thing about clocks is that the more intriguing they are to look at, the more precious time is wasted. This steampunk clepsydra is no exception. A clepsydra, or water thief clock is an ancient design that takes many forms. Any clock that uses the inflow or outflow of water to measure time could be considered a clepsydra, even if it uses electronics like this steampunk version.
[DickB1]’s sticky-fingered timepiece works by siphoning water from the lower chamber into the upper chamber on a one-minute cycle. An MSP430 and a MOSFET control the 12 V diaphragm pump. As the water level rises in the upper chamber, a float in the siphon pushes a lever that moves a ratchet and pawl that’s connected to the minute hand. The hour hand is driven by gears. A hidden magnet and Hall effect sensor help keep the clock clicking at one-minute intervals.
Although [DickB1] doesn’t tell you exactly how to replicate this clock, he offers enough information to get started in designing your own. Take a second to check it out after the break.
We recently went through our twice yearly period of communal venting called adjusting for daylight saving time (DST), or British Summer Time (BST) as it’s called in the UK. But why are we changing the time? Seriously, who caused all this? Does it do any good? Do we still need it? And what can we do about it? As it turns out, most of us want it, as you’ll see below.
There are few things to which we pay as much attention as the passage of time. We don’t want to be late for work, or a date. Even more importantly, we don’t want to age and die. Good time keeping is an all important human activity, and we started to worry about it as soon as we abandoned our hunter-gatherer lifestyle and agriculture and commerce emerged.
Measuring time needs two things: a repetitive process to mark equal increments of time, and a way of tracking and displaying the result. The first timekeeping devices relied of course on the movement of the sun. Ancient Egyptians, around 3500 BC, built obelisks that, by casting a shadow on the ground at different positions, gave an approximate idea of the time. Next came the use of some medium that was consumed at a regular pace: candle, incense, water and sand clocks are examples. A great advancement came with the advent of the mechanical clock, and here is where the escapement mechanism appears.