Intro: 8*8 LED Dot Matrix Clock
I got an LED module a few days ago and was thinking about using it for playing Tetris or a Snake game, but I thought that would be lame. So I thought: “why not make a watch?”
As there are only sixty-four dots on one Matrix module, I had to make a smaller dial and figure out a new way to show figures on the screen. Check the video below and guess what time it is.
Beep beep beep! Can you read it? It’s between 11:59 and 12:00.Let me show you how to read it:
Step 1: How to Read
The red dot in the center turns on and off at 1 second intervals continuously, representing seconds.
The blue section represents the hours. Starting at the top, each corner of the square represents 12, 3, 6 and 9.
The orange section represents the quarter of the hour. 0 - 14 is shown in the upper right corner, 15 - 29 is shown in the lower-right corner, 20 - 44 is shown in the lower-left corner and 45 - 59 is shown in the upper left corner.
As you can see in the video, when the triangle is shown in the upper left corner, 14 red LEDs along the outer perimeter are active. That means it’s 59 minutes past the hour. (45 + 14 = 59 minutes).
Then the dots in the upper right corner are brightened. Fifteen red LEDs are active, which represents zero.
I use 15 active red LEDs to represent 0/15 so as to make all dots brightened when 9:15 shows up on the LED module. You can also change the code and use 15 inactive LEDs to represent 0/15.
Confused? This is not intentional, forgive me!
Showing the time on an LED matrix can be tricky, so I used the following system to achieve it:
Eight is an even number, so if the number of activated LEDs that are brightened in any row were an odd number, the overall image shown on the LED module would be asymmetric. I tried as many possible solutions to the problem and then figured out the above way to display the time on the LED matrix.
See below for information about how to make this fancy dot matrix watch:
Step 2: COMPONENTS
Step 3: CONNECTIONS
Connect all the components using the diagram below for reference:
Note: SCL & SDA on Uno is on the left of the digital interface Aref. To find it, you may check the back of UNO first.
Step 4: INSTALLATION OF THE LIBRARY FILE
Step 5: RECOGNIZE THE ADDRESS OF DOT MATRIX MODULE
I2C address bit
There are three vacant pads on the back of the module. Zero represents off; 1 represents short-term connection.
Step 6: CODE BURNING
Once you fully understand the code, you can edit it and display time on the dot matrix watch in a different way. Be creative!
Please see the attachment to find the code