I could not really find any great Blender models of the Arduino Uno on the internet, so I decided to make my own. Mine was made entirely from scratch and does not use any image textures (except the wood in this demo). It features most of the details of the Uno, but does not have the printed circuitry. It was modelled off an image and some eyeballing for sizes, so it may not necessarily be to scale, but it looks close enough for Blender work. Even the text is there, using the default Blender font. The Arduino logo is actually a mesh of a circle. The most notable chips have the proper text on them, and the plugs even are shaped like sockets.
See the bottom of this post for the .blend files, or read more to see how it was done.