I've been looking for an e-ink maps/GPS device for years. I feel like turn-by-turn would be a waste of the e-ink, but more like, topo maps that I can use with a compass, and just power the device on for a moment whenever I want a new map tile.

But none of the e-ink devices I've found have an internal GPS chip, and I haven't dug deep enough to find if any have an internal UART or i2c pins to which I could attach one. (Nor do I have any clue how to make the OS see it after I do that.)

It looks like this is just using BlueNMEA to inhale GPS sentences from an external device, which is.... something, I guess.

Although not the most elegant solution I like the idea of it, both from a batterylife standpoint, as well as a legibility perspective.

Building a custom solution with some microcontroller a gps module and a small E-Ink display sounds doable and like a fun project.

For a small display, you might be interested in the Beeline products: https://beeline.co

I'm myself considering one of these.

I'm looking at https://beeline.co/pages/beeline-cycling for example, but it isn't clear what display they're using, it looks like regular LCD, not even anti-glare? What's nice with e-Ink, is that it's highly visible even in strong sunlight (extra so when they've focused on anti-glare), while LCD even with anti-glare can be difficult to see.

Simple and clever. One concern I have is in my experience the kindle displays are quite fragile, I would worried it would break mounted like that.

Such a rainy day! SCNR

From the article, it seems the project is based on a more advanced setup by David Schneider: https://spectrum.ieee.org/build-a-readable-bicycle-computer