Originally, I bought an "Arduino" Mega 1280 on Ebay. I didn't realize I was buying a counterfeit board, but the price was terrific and I should have known. I wanted the mega because it had more ports and more memory, so I assumed that meant I could do more with it than the other boards. Unfortunately, I found that I couldn't use a lot of the standard shields that are available. I bought a PoE (Power over Ethernet) shield from Sparkfun that didn't specifically say what boards it worked with, and discovered that it would not work with the Mega boards. The digital pins on other boards are combined with other pins, but on the Mega, the digital pins moved to the end of the board. I tried a workaround, but had no luck so I went ahead and bought an Uno board.
The mounting holes are a bit different on this board than they are on the longer Mega board
. I made some more standoffs for the Uno and mounted it to the Plexiglas alongside the Mega.