You're driving around aimlessly when you suddenly notice that, in the car just behind you, there is a beautiful and cheerful girl, singing by herself. Wouldn't it be nice to communicate with her, to throw away an innocent compliment and "attract" her attention? Or maybe you really need to notify something on the road, call names, make fun or even advertising something: your company, a trademark, your candidate, whatever. This project is about creating a smart sticker that would enable all these sort of things to happen.

With four 8x8 red LED dot matrix boards, like the ones available in DX, I was able to buld a 16x16 matrix board, sizing approximately 6.5x6.5 centimetres. It's little, but yet very visible. The downside of my final board is that each one of the tiny 8x8 matrix boards ended up in one different position, implying on several calculations to translate a 16x16 matrix into 4 8x8 rotated matrix at once.

After spending some time toying around with the source code, I realized that it would be very difficult to rely on the Arduino to make all calculations/translations in runtime and yet display the information within an acceptable time. So I decided to create a drawing board, with HTML& Javascript, to help me out with the drawing issue, and coded all the necessary math in PHP for translating the 16x16 matrix into 4 8x8 matrices.

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This board can be seen in http://www.carr3r.com.br/matrix . I also coded a PHP script that calculates all the frames necessary to fade in and fade out an image, so all the Arduino was to do is to read an array of matrices and display each element of it (actually it slides a frame towards left, right, up and down - http://www.carr3r.com.br/matrix/transition.html).

The video below shows the current state-of-art of this project.

Next steps:

  • Create several animations;
  • Install an infra red sensor, so I can control what the board displays with an ordinary infra red remote control.

 

 

Updated on March 24, 2014

Material list:

Circuit Diagram (made with Circuit Diagram and GIMP):

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Necessary library: LedControl.zip (documentation)

Source code: _16x16RedDotMatrix.ino