My awesome macropad!

Im attempting to build a little keypad that plugs into mac to add layers to the keyboard. Think G-Shift. This way, I can just press a little button with my left hand and access a whole world of hotkeys with my right. For example, I HATE the little tiny arrow keys and the fact they are so far from my hand makes them impossible to use. Now imagine you can just press a button and use I, J, K, and L. So much nicer. Want to change caps lock to another key, but all your regular keys are used up? Solution: just use a layer! This will be heavily relying on Karabiner Elements to do the layering, I'm just making the button, which will have some other cool elements.