Interesting weekend project for those who still remember the awesome game or just to awake in your kids the knack for electronics here is the Space Invaders Button.
Fairly easy build, having the ATmega16P at the heart controlling an 8×8 bicolor LED matrix which will display animations of the gameâ€™s spaceships. Principle of operation is simple, the rows of the matrix are driven by a npn transistor in an emitter follower configuration.
This transistor provides the boost of current needed when two or more leds from the same row are on. The state of the ports driving these transistors is set on â€śhighâ€ť logic level. You can now command each LED to light the color you want by setting the assigned port to “0”.
The ATmega16P will draw a small amount of current and can be powered by a 3V cell battery. The PCB is of small dimensions since SMT components are used, it’s even smaller than the LED matrix and thus hides nicely behind it.
It’s an easy project with little chance of failing and offers a nice lesson on how to handle the ports of your microcontroller. If you are doing this just for fun and you donâ€™t care about dimension than the SMT can be avoided so that you can use the controller for other projects.
Space Invaders on a LED matrix: [Link]