I designed a bunch of business card prototypes, exploring what designs you could do within the limits of industrial PCB design constraints.

I made ones for a bunch of logos that I liked.

The cards are just an ATtiny24a and a charlieplexed LED matrix. The battery is a tabbed CR1616, which is the same thickness as the PCB, and installed it in a matching drill hole in the PCB. Unfortunately this requires soldering.

The animation is trigerred by a resistive touch pad. Unlike capacitive touch, resistive touch does not require an active ciruit to operate, so the microcontroller can remain in ultra low power sleep until activated, though the sensitivity depends on the dryness of your fingers. You could design a circuit that uses virtually no power at all using this method.

With a low part count this allows a cost effective design.

Since I wanted to leave the main field of the card as clear of traces as possible to make space for art, this project inspired me to create my first algorithmic LED optimization program to assign nodes in the charlieplex topology as efficiently as possible. I spent way too much time on this but the difference was dramatic.