2025
I wanted to give my girlfriend a unique and lasting anniversary gift. I made this small device that displays mostly memories, but also inside jokes, quotes, song recommendations, etc. It updates automatically every day to match the day of the year.
This is easily the smallest physical size product I've ever built. To save time and money, I deciced to use the Adafruit Feather ThinkInk board instead of making a custom PCB. The device also features a 2000 mAh LiPo battery for a years-long battery life, a USB-C port for charging and reprogramming, a pinhole reset button in the back and two buttons in the front for scrolling.
I had a cheap USB-C breakout that didn't end up working due to wrongly wired CC-pins. For the new breakout board I had to make a new internal brace (the green part).
New breakout soldered and attached to new brace along with buttons.
The front plate has two buttons.
Checking the board voltage after installing the battery.
The tolerances I had designed turned out to have been way too optimistic. The front plate stuck out from the enclosure slightly.
To counter the poorly fitting front plate I put black silicone glue all around it. Once dry, I scratched it slightly with 400 grit sandpaper which made its color match with the front plate.
The oak enclosure was finished with two coats of colorless furniture oil.
Routing the USB-C port to the outside of the enclosure turned out to take a huge amount of time because of the spatial constraints. If I were to build this again, I would implement everything necessary from Adafruit's design to a better form factor for the enclosure. This would eliminate the need for the secondary Type-C port and would allow to put the battery next to the board as opposed under it. This would save almost half of the thickness of the device. Maybe I'll do this for another anniversary years from now to also compare how far E-Ink technology has come.
