Just before arduino became a thing I had an idea to create a device that could read your your text messages by tapping out morse code on your skin somewhere, like your hip or arm.

It would never be able to keep up with modern levels of connectivity, but at the time I thought the bit rate might be high enough to be interesting.

But by the time arduino landed I was more interested in visual information radiators. I soured on the whole idea when I discovered that flow control hardware wasn't on any of these boards. Made it feel very much like sticks and rocks.