When you’re driving down the road, and someone is tailgating you, don’t you think it would be nice if you could actually communicate with the driver? Sure, there are some hand signals that you can always use, but those aren’t exactly polite. Well one hacker decided that they wanted to do that very thing, and set out to make an LED display that could convey messages to the person driving behind them.

The system is composed of a mesh grid with roughly 600 LEDs. These lights are controlled by an ATmega AT89C51 microcontroller, which stores the messages you want displayed. With the flip of a switch, you can kindly inform the people behind you to back off, go around, or just about anything else you can think of. If you should decide to undertake this project yourself, the first thing you should do is check your local laws regarding lights on your vehicle. Some areas won’t allow certain colored lights to be used, while other areas may prohibit the use altogether.

via HackADay