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  • Writer's pictureAtchareeya Jattuporn

Midterm : Whole World Clock


My sister, my mom, and I are in a different corner of the world. I always confuse when thinking about when is the best time to call them. So I decided to make this clock to observe the time in every corner of the world.

This clock will only indicate the hours of each time zone. Users can notice which hand is which timezone by viewing the base of the clock, which will be a label showing the timezone of each hand. Before plugging in the clock, the user has to rotate the last hand of the clock (+12) to match the 12 o'clock. and then the clock will calculate the time.

I also did this digital sketch to test the idea. The visual was not as interesting as I thought.

Coding & Circuit

I used the RTC library for the Arduino and set up the time base on Epoch time.

At the beginning of the sketch, the Arduino will get the time from the RTC library and set up the clock hand to the angle of the time now.

In order to calculate the angle, I found this tutorial to set up an accurate angle for the stepper motor. Here is the explanation of my calculation

My stepper motor is Nema17 which has 200 steps.

Each step will rotate 1.8 degrees. (360 / 200)

In an hour, the clock will rotate 30 degrees. (360/12)

So the motor should rotate 16.67 steps when the hour has passed (30/1.8)



I cut the acrylics and woods with the laser cutter. I decided to attach the motor on the side of the clock. I'm almost happy with the fabrication part except the piece is not symmetrical because of the motor attachment. To improve it in the future, I would love to find another way to attach the motor.

Movement testing

My feeling after the observation

- The clock is ticking every hour and there is motor sound when it ticks. So, I feel like it is an alarm that the hour has passed and how fast the time flies in a day.

- I really loved the movement of all the hands. I imagined all the clock in the world is laying on top of each other, the hour hand going to look like this.

Room for improvement

- I want to add Neopixels to indicate the day and night. The light will turn on that time zones are daytime otherwise the light is off.

- It would be nice to find a way to set the angle of the hands. Right now, I have to adjust it manually.

- I also want to smooth the movement of the clock right now it has a very sharp movement.


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