What to do when you find a single keyboard key connected to a plug? Listen to a good podcast and hack together a physical escape key as a gift for someone who just plunked down a ton of money for one of the new MacBook's without a real ESC key. The inexpensive DF Robot Beetle Arduino Leonardo clone and Arduino Keyboard library make it trivial to send the ESC keypress to your computer. The button is connected to Ground and D9 (I included a 10k-ohm pullup to +5V since there were a couple of feet of wire to the button). The LED on D13 indicates the button is pressed. Code was trivial (in a follow-on post). Most of the time was spent cutting a squarish hole for the USB connector with an X-acto knife in the plastic enclosure. You'd need a USB Type-B to USB C cable to really use this with a new MacBook Pro.
LOL. I know! But I don't have a new MacBook :-(. One would have to buy a USB C to Micro USB cable for this to work. I thought about trying it out at an Apple store but not sure if those people have a sense of humor...
The funny thing is that the new Macbook doesn't even have a USB type A port ;-)