Specifically, Paper Mac reused an original Mac Classic II case, but the internal components were replaced by a Raspberry Pi 3 paired with a 16-color e-ink screen in grayscale produced by Waveshare. As for the software, instead of starting the Apple System 7 operating system, a customized software inspired by it is used, called Pseudo 7, which shows several images from the owner's Google Photos account.
Photo Credit: Dave Luna
Dave Luna commented on this process like this:
I didn't want to go through Google Photos API authentication, querying, and caching. There was nothing new or fun about this process. Instead, with this system the Chromecast would have done all the heavy lifting involved in managing the photos, while I would have learned more about the camera port that I had never used before.
To give even more "authenticity" to the 'work, Paper Mac uses an Arduino that converts the Apple Desktop Bus (ADB) to USB to use original Apple peripherals and produces classic Mac sounds via a set of USB speakers installed inside the case. Some keys have specific functions, such as activating clock mode with "C", taking a screenshot or turning off.