Single Digit Clock!

In this tutorial I present to you the construction of a clock with a single digit, made of paper and cardboard. A simple and spectacular project that combines design with microcontrollers and does not require a 3D printer

1.Arduino Nano

2.button

3.breadboard

4jumper wires

5.servomotor SG90 x7 pieces

8.infrared module

9.RTC Clock module DS1307

10.Arduino IDE

11.Visuino software

12.cardboard

13.colored paper

14 glue and hot glue (glue gun)

15.cutter

16.scissors

17.ruler

The construction of the display is the most delicate part of this project. for the base of the display, I chose a thicker cardboard that I cut from an A4 paper, on which I pasted a black colored paper for the background.

I cut the 7 segments of the display from a thinner cardboard, a white box. On the back I pasted black paper to "get lost" in the background, and on the front I chose the color green. You can use any other color combination, but the black background hides the servos better. You choose the color of the segments to be in contrast with the color black, white, green and yellow.

The vane that attaches to the servo motor wheel I glued one in the center of the vane to each of the 7 segments with hot glue with a gun, as you can see in the images. The elements are light, they are made of thin cardboard and paper and do not cause stability problems.

I glued the actuators using the same method, also with hot glue. Attention: observe exactly the placement of the motors, with the gear and the connecting wires exactly as you see in the photos, otherwise the elements will rotate in the opposite direction.

Before inserting the segment into the servo motor wheel, move the position of the servo motor gear to the middle of the stroke. To be able to move 90 degrees in one direction, 90 degrees in the other direction. Practically position the wheel in the middle.

1. The electrical diagram is presented in the attachment. We distinguish pins D2...D8 which are the control pins of the 7 servomotors. Pin D2 is assigned to segment "a" of the digit, D3 to segment "b"....up to D8 assigned to segment "g'". Be careful to put the servomotors in this order to the Arduino pins, otherwise the characters will be wrong.

1. see in the attached images what are the elements of the digit a....g and their placement in the number

1. Attention: supply 5 volt energy to the servomotors separately from the Arduino microcontroller. It cannot support the current consumption of such a large number of servomotors and you risk damaging it! The power supply of the servomotors must be at least 5 volts/2 Amps!

1. We load the code in Visuino or Arduino IDE. You can find the code in IDE format in the attachment, as well as the Mitov libraries. If you use the Arduino IDE, copy the "Mitov" folder to the Arduino libraries folder in My Documents.
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3. since a time setting system is difficult to achieve with a mechanical display with a single digit, the time setting is done at a time established in the code. See in the video how you can change the time if you want. It is set at 12:00 am. Take as reference a clock and at 12:00 press the reset button of the Arduino Nano, at this moment the clock is correct.
4. https://app.box.com/s/aynowhr3pwuut4y9otc2zcw6vy3oa7u2 Mitov Libraries

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2. After loading the code into the Arduino, we feed the servomotors and press the test button. The display should count from 0...9 for 10 seconds at a faster rate. After the ten seconds, all the elements are in the standby position, the one seen in the photo, no segment is visibly colored in green.

1. At 12 a.m. briefly press the reset button on the Arduino board. At this moment the watch is ready for use.

1. Because a mechanical display with a single digit could not sustain repeated movements continuously and for the protection of the servomotors, the clock will show on the display only when the infrared module detects an obstacle. When an obstacle is detected, the watch will show the exact time in cycles for 3 minutes, after which it will switch to stand by waiting for a new command. Attention to the battery on the DS1307 module, the 3 volt one. Make sure that it is in good condition so as not to lose the time settings in case of an accidental interruption of the power supply.
2. Enjoy!