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Measuring Time
The human mind has been fascinated by devices that keep track of time for thousands of years. A wide range of ingenious methods have been employed by different cultures including Chinese marked candles, Egyptian sundials and Roman clepsydrae, that used water pouring from a container to mark the passing hours. The classic hourglass (still useful for boiling an egg) led on to more sophisticated mechanical clocks from Europe. The development of these technologies has continued in search of ever-more accurate means to measure the passage of time. The evolution of the cheap wristwatch at the end of the 20th century used quartz crystals to keep time and they became the dominant timekeeping technology until the arrival of the smart phone. Today, we have atomic clocks that can keep an accuracy of one second in 300,000,000 years!
Coordinated Universal Time
The internet provides an opportunity to connect a range of devices that can sense the real world, talk to each other and exchange information thereby forming the internet of things (IoT). Of course, clocks are now one of the many devices that can access the internet to retrieve a time signal to display the time accurately anywhere in the world. In the internet age, Greenwich Mean Time, the world standard has been overtaken by coordinated universal time (UTC) to regulate clocks (and computers) around the world. In order to synchronise computer systems around the world, the Network Time Protocol (NTP) was invented and can ensure a computer has the correct time within a few milliseconds of UTC. As we now have the technology to accurately measure time from any location with an internet connection, perhaps our efforts should be put into creative ways to display the time after all, we dont have to worry about replacing the candles or turning the hourglass upside down any more. This clock design is based on LED neopixels (WS2812) which are strips of connected lighting elements. Each element is made up of red, green and blue (RGB) LEDs and the brightness of each colour can be independently controlled, providing a possible 16.8 million colours. A microprocessor is needed to retrieve the time from the internet and decode which LEDs to illuminate. It needs to generate the binary codes that are sent down a single wire to switch the individually addressable LEDS on and off. Neopixels are available as long flexible strips and matrices but this design uses a neopixel ring made up from four quarters that each have 15 neopixels. When soldered together into an almost continuous ring, the 60 neopixels can easily represent the 60 minutes found on a traditional clock face.

- 3D print the clock housing - files can be found on Thingiverse
- Quarter circle neopixels WS2812 15 pixels x 4
- ESP8266 Wemos D1
- Resistor 470
- Electrolytic capacitor 1000F
- M3 x 12 countersunk machine screws x 2
- M3 Nuts x 2
- Multistrand cable
- Single strand wire (for soldering bridges)
- Superglue
- Female Power Jack Socket
- M2 self tappers x 2
- 5V 3A power supply”

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