In many households, especially those with more than one person, there’s some sort of central area with a whiteboard, series of sticky notes, or other means to convey messages to passerby. This works well enough, but of course this doesn’t allow you to update things off-site, or see the contents when you’re not at home. To solve this issue, robotics aficionado James Bruton created his own ePaper message board, controlled by a Raspberry Pi 4.
Bruton's first idea was to simply plug an ePaper panel to the Pi to act as an HDMI display. However, after finding a 10.3” HDMI model at well over $500, he instead looked at a smaller option that is controlled by a Raspberry Pi HAT, for about a tenth of the price. The issue here is that this smaller display doesn’t simply plug in and function as the Pi’s main screen, but needs a bit of driver setup to get working correctly.
After working that out, he then set it up to update via a Google Docs spreadsheet, which can be accessed from anywhere using a mobile phone. The Pi pulls info off of this document via the Docs API, using a service account and a Python script. The Pi checks the spreadsheet every five minutes, comparing cell data to what was stored previously, and updates the e-paper screen only if there’s been a change.
It’s a clever build, and something that could even use an older Pi model for better power efficiency. CAD and code are available on GitHub, and more info is available in Bruton's video description.