Show HN: Open-Source eInk Bike Computer

The semi-interactive walkthrough on the website is really cool, great way to show the UX.

I've always wanted to use a round display and an 18650 to plop a mini bike computer into my headset (replacing the cap). There was a Kickstarter years ago for a project doing that, but it seems to have fizzled out

Within 10 seconds I was convinced I needed to try this.

For me, the next step for this is taking all the sensor data recorded for a ride, and loading it into my own fitness tracking database that I own, control, and isn't tied to someone else's profits.

There’s no mention of the wheel sensor. How does it get the bike telemetry?

I love my eInk displays, I love my bike head unit.

But I don't see how they both fit together honestly.

  The pros of eInk:
  - low energy usage -> don't matter, current GPS units have +30 hours of battery life already
  - low eye strain -> don't matter, you don't look at the screen for hours at a time
  - visibility -> don't matter, current GPS units adapt to ambient light
  - angle visibility -> don't matter, the screen is right in front of you

  The cons of eInk:
  - refresh rate -> yeah, I don't want the map display to be laggy
  - visibility in the dark -> tunnels, tree cover... I don't want to my GPS to be invisible
  - lack of color -> colors provide lots of information on the map display

This is great, I just saw your post on X. I'm also building a bike computer!

eInk is the right display tech. I think this will do really well.

That said, I don't love needing a separate device, I really prefer to just plop my phone on my handlebars. So I'm building a bike computer app for iPhone: https://x.com/mholt6/status/2090529441944687087 (trying to get Apple to approve my developer account / business info, but they're hung up on my website of all things).

Phones are definitely not ideal in terms of display and energy use, but, I have found that with proper optimizations, energy use is a non-issue. To offset display problems, the app has several ride modes: a rich map display with 3D road or satellite view; a high-contrast wireframe map that looks great at both high and low refresh rates because it has no analog-style gauges; an instrument panel dashboard view; and a voice-only mode that has big touch zones for on-demand voice updates, using a state of the art mobile voice synthesis model. For connected radars, the app also renders radar data and has a screen like Tesla/Rivian's autonomy displays.

The app automatically manages thermals by switching modes to preserve battery life.

In my testing so far, by managing energy, making really good voice feedback, and using high-contrast screens (every mode other than the "rich" map), even a dimmed iPhone display is quite a usable bike computer in high-altitude sunlight.

But man, that eInk looks so clean and nice. Definitely the superior display! Nice work and I hope to learn some things from it!

Very cool! I made something similar recently with my Xteink X4 ereader - difference being it served as a UI for sensors connected to my phone. Getting the ESP32 to communicate directly to ANT sensors is pretty wild!

Wow. You managed to receive ANT via BLE hardware?! I didn't know these two protocols were so similar.

Hey this looks neat, I’ve been thinking on trying something similar. I’ve not encountered the ANT protocol, what bike ya using? Is it a higher level thing that your display is giving you, or something your controller uses? I know Bafang uses CAN protocols in their newer e-bike systems and a lot of manufacturers (especially Chinese) use a proprietary UART protocol to stitch things together on the cheaper end.

The mess of different implementations makes it really hard to hack on and share this kinda stuff.

AI does make it really easy to figure out these protocols now so that’s nice I guess. I just flipped my bike upside down and hooked up a logic analyzer and it took LLM no time to figure it out… it is really impressive

Would love to see video of the application in action. Was recently researching eink displays for motorcycle navigation, but the refresh rates were not up to par for realtime automotive navigation..

Battery of my Cubot King Kong Mini is slowly dying. I use it with OpenTracks to record my commutes and use as bikecomputer and sometimes Osmand+ for offline navigation. I am searching for alternative, which needs to be waterproof and cheap (my commutes luckily includes downhill trails sometimes - I dont want to break expensive device). The title gave me high hopes, but I suppose I need to keep searching.

Very cool. I was messing around vibe-coding an HR monitor on a LilyGo T5.

My thought was I'd love to set an HR zone and then connect it to my e-MTB and have it change power to keep me in a zone.

The refresh rate on my device was horrible, and the models (this was a few months ago) struggled to create a historical line plot of my HR.

Wow, this looks amazing!

I hope we can get a better suited hardware though. Larger buttons, smaller device overall. 4.7" sounds huge, almost size of a phone.

Very cool! Did you consider Protomaps for the map tile format at all? It's a pretty clever way of storing everything in a single file and their tooling is pretty nice.

I can't imagine using this in the Netherlands with random rain. The tradeoffs are hard to accept, wondering how it looks and performs in various weather conditions, and if a physical buttoned shell is worth it...

Does this work well in direct sunlight? I know a lot of e-paper panels struggle to refresh in strong sunlight. The waveshare panels look very faded if they update while exposed to UV.

Wow, this is really cool. I really needed something for my neo retro build, this might just fit the bill.

Insane! Quality on the ANT too!

I've found e-ink displays super fragile for this use case. They break from a little fall, or even from the constant shaking.

awesome stuff. I have a Wahoo bike comp but would love to use an OSS alternative

the dealbreaker for me is whether it could eventually work with the Garmin Vario radar (which the Wahoo supports with a nice visualization) -- that is _literally_ a life saver and I no longer ride without it.

I love this. How do you house & secure your lily on your bike?

Any open source GPS locator for bikes?

Damn, this looks cool

Funny, I just got done researching the Coros Dura, another eInk bike computer.

This is cool, but I bet it will be a grind trying to get to Garmin levels of battery life. They just have it nailed, and an Edge 550 that's ¼ this size can run for over a day, despite its emissive display, and they don't seem to suffer from display scaling since the larger Edge 1050 runs for even longer. That is to say that the larger battery in a larger device more than compensates for the higher display power requirement.

Anyway one thing I think would be nice is if the GPS radio can become a peripheral. Then with that architecture could the head unit just get GPS from your phone?

great!

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