Today I tried to make something with the Arduino RGB LED matrix shield on hand. This idea came up when I was going to bed last night. I what to let the color of the matrix changing according to the change of my car engine’s RPM (or some other realtime data, maybe throttle position) as well as the character displayed on it.

This is what the RGB LED matrix is like when stacked on an Arduino board.

With the example code provided with the part, it’s really easy to get the matrix lit up and show some characters.

It doesn’t take me so much time to master the control of the RGB matrix while in my mind I am making a fancy device together with the vehicle OBD-II data readout that I already mastered and made into a library.

Now I got this on my car (see the video). The number displayed reflects the engine RPM or engine load percentage (e.g. 3 for 30%, 9 for 90%+). The color is also changed with the change of engine RPM (e.g. turning red after 6000rpm).
Some demostration videos: