The brain has over 25,000 nerves per sq cm meaning you can feel nanoscale ridges.
The brain can't handle all of those signals so it reduces the tactile resolution to 1 sq mm.
The brain naturally senses rhythm and patterns better than a static signal.
So we made the display as a large matrix of small, square millimeter vibrating pixels. They are designed to vibrate only about 10 microns, so they can be small and naturally vibrate in the region a brain can detect comfortably. Each pixel is a micro scissor lift which is driven by a simple electric signal.
I made the pixels to vibrate indefinitely and to never break even under compression from someone pressing down on them. The final design was made using photolithography and driven by laser cut piezo electric actuators, after comparing designs made from casting, 3D printing, and MEMS techniques.
The pixels are 5 mm long, by 5mm high.
Putting it to work
The final stage of the project were to pair different outputs to easily recognizable patterns that different people can discern.
It was combined with a computer vision program co-developed with MIT that can recognize emotion. The output of the computer vision program would then be pushed as a recognizable pattern on the device.