Show HN: Open-Source eInk Bike Computer

(opentrailpaper.com)

74 points | by stingrae 1 hour ago

12 comments

  • mholt 19 minutes ago
    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!

  • tuchsen 37 minutes ago
    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

    • matsemann 0 minutes ago
      Ant+ is for connecting sensors and other stuff. Like heart rate monitor, power meter, control resistance on a trainer etc.
    • monknomo 25 minutes ago
      ant+ is a garmin protocol that is very common with fitness gadgets and in the bike world. It's a bit like bluetooth, but lower energy usage.
  • pilina 33 minutes ago
    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.
  • kccqzy 43 minutes ago
    Wow. You managed to receive ANT via BLE hardware?! I didn't know these two protocols were so similar.
    • stingrae 31 minutes ago
      yes. they luckily the same phy, 1 Mbit/s GFSK modulation.
  • evrimoztamur 43 minutes ago
    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...
  • dinan 40 minutes ago
    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.
    • stingrae 29 minutes ago
      i have ridden with this unit over five hundred miles and not had any issues. though SF Bay Area summers arent as tough as other places.
  • zsoltkacsandi 10 minutes ago
    I've found e-ink displays super fragile for this use case. They break from a little fall, or even from the constant shaking.
  • dumbmachine 31 minutes ago
    Wow, this is really cool. I really needed something for my neo retro build, this might just fit the bill.
  • memoryfault 24 minutes ago
    I love this. How do you house & secure your lily on your bike?
  • maxrev17 30 minutes ago
    Insane! Quality on the ANT too!
  • Lucasoato 36 minutes ago
    Any open source GPS locator for bikes?
  • arpanghoshal07 45 minutes ago
    great!