Size and shape:
The current implementation of the Haptic Input device is more a proof-of-principle that a handy wearable. The actuators in the frame are quite bulky and heavy, and the relay board is also quite big. However, one of the biggest problems is that the device gets very hot after ~10 minutes. I think there is a design flaw with the power supply. The actuators are just coils and I think that if they are activated they draw as much power as possible. Because the current power supply can deliver up to 10 Ampere, this is a lot of energy. Maybe it is better to use a lower Amperage. but take in consideration that there should still be enough energy to push into the skin.
Next versions should be a lot smaller and lighter. I can see two ways of doing this.
One is to use a flexible patch made out of some silicon rubber that can be glued onto the skin. In the patch channels should be made and connected to a grid of cavities. Using air pressure individual cavities can be inflated to generate the input patterns.
Another option is to use electricity directly to stimulate the skin receptors directly without touch. This should make the device a lot simpler and smaller. A 12V battery should be sufficient to power the device and stimulate the skin.