There are many inexpensive options for Arduino compatible displays today. When I put this project together in 2011 I used two 20x4 blue LCDs which I show in the video below.
💡Lesson Learned: If I were to build this controller today I would probably use something like the 3.2 inch TFT LCD I used in my Arduino Accelerometer project, which you can pick up from Adafruit. You can also find these on eBay or AliExpress by searching for "3.2 inch TFT LCD" and usually go for less than $15! However, make sure they are Arduino compatible and the software libraries available for the Chinese imports may be a little trickier to use. I have one I've been meaning to try out. On the other hand, the Adafruit displays have a well-developed library with fonts, drawing utilities, and other things that are well tested which may be worth the additional cost for less frustration.
