“I had the calculator class running on my Mac. I had some Arduinos, seem to always have some about, and a 2.8” capacitive touchscreen from Adafruit. I put the two together and, well.. It just didn’t have enough RAM to do much. I got it to work. But I could only put on a subset of the buttons. Sad day, so I put it away and went on to other things. Then one day I ran across the Uncanny Eyes project by Phillip Burgess. That introduced me to the Teensy 3.2 µ processor. Its like an tiny Arduino with LOTS of RAM.”