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<\/p>\nThe field of control engineering began with mechanical clocks thousands of years ago.<\/p>\n
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SUN – WATER & SPRINGS<\/b><\/p>\n
II.A.1 SUN CLOCKS to fight starvation<\/b><\/p>\n
Everyone is familiar with sun dials which can mark the hours of the day based on the position of the sun, but sun was also used to mark seasons. The Fajada Butte at Chaco Canyon, New Mexico uses a dagger of light filtered between boulders on a rock wall to show how close we are to the next equanox or solstice. Tracking the moon and sun over seasons was important for telling farmers around the planet when to start planting or when to harvest. Clocks were a tool used against the forces of starvation as entire seasons of crops could be destroyed by planting too early, or harvesting too late.<\/p>\n
II.A.2 WATER CLOCKS for justice, industry and art<\/b><\/p>\n
6000 Years ago<\/b> in China, Egypt and Greece we used water clocks to measure the passing of hours. Ancient Greeks figured out how to use gears and wheels to make draining water consistantly drain, the clock was called a \u201cclepsydra\u201d. Why would early people need to know the passing of hours in what many people today view as a era with a \u201csimpler\u201d life \u201cwithout all the technology\u201d?<\/p>\n
Early uses:<\/p>\n
![\"\"](\"http:\/\/www.edisontc.org\/ui\/files\/2022\/11\/WaterClock-drain700.jpg\")
The \u201cInvention\u201d of Hours:<\/b><\/p>\n
With the water clock the Egyptions divided the day into 12 units of daylight, and 12 of night time. This worked during the equanox (2 days a year) and the rest of the days the \u201chour\u201d would vary in length. Hipparchus of anchient Greece proposed that the 24 parts of the day should remain equal in length, and the idea of the \u201chour\u201d was born. There was a problem however, the average person was not located near or did not have a sophiscated water clock. With most people being unable to keep track of the consistant hour they did not adopt the idea. It was only 1400 years later that Europe changed to a true \u201chour\u201d being exactly 1\/24th of an earth\u2019s single rotation.<\/p>\n
Minutes! Who Needs Them?!<\/b><\/p>\n
When Hipparchus took the sexagesimal system already used to divide up a circle into 60 parts to divide the hour into 60 parts, his idea was once again fell on deaf ears. Peasants and leaders alike didn\u2019t see the need to be so detailed as to use Hipparchus\u2019s 60 minutes and 60 seconds, so it took over a thousand years before these incriments of time became standardized and adopted by the masses.<\/p>\n
![\"\"](\"http:\/\/www.edisontc.org\/ui\/files\/2016\/02\/Picon-Ammeters300-1.jpg\")
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II.A.3. SPRINGS for Kings, War and Cuckoo Sounds<\/b><\/p>\n
If you remember from Unit 1 it was types of round springs which allowed us to first accurately measure the quantity of electricity in an electric meter. Two hundred years before that these springs gave us grandfather clocks and wind-up clocks.<\/p>\n
Advantages:<\/p>\n
Pendalums:<\/b><\/p>\n
Due to the experience of creating water clocks, the basic gearing of \u201cclock hands\u201d was already understood, so how could we make a predictable and uniform oscillation to replace the spinning water driven wheel? A pendalum was the answer.<\/p>\n
Taking a rigid swinging rod with minimal resistance at the bearing was an obvious answer to creating an oscillation. What was not obvious was how to keep it swinging. The invention of the spiral spring would help.<\/p>\n
Turn the knob (transfer energy from the human) this tightens the spring (stores a reservoir of energy), and through gearing keep giving a little \u201cpush\u201d to a pendulum to keep it going. From here we can let each swing move a wheel that drives the seconds in the clock gearing.<\/p>\n
The escape wheel turns and the anchor fork both nudges the pendulum to keep it going, and it stops the escape wheel. It’s necessary to stop the escape wheel so the springs don\u2019t just use up all the energy.<\/p>\n