Show HN: Open-Source eInk Bike Computer

(opentrailpaper.com)

95 points | by stingrae 1 hour ago

19 comments

  • wiether 17 minutes ago
    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
    
    Anyway, as long as you have fun doing this and some people enjoy it also, congrats!
  • nickmcc 8 minutes ago
    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!
  • neoCrimeLabs 13 minutes ago
    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.

  • tuchsen 1 hour 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

    • __d 10 minutes ago
      ANT+ is basically dead because of an EU legal requirement to ensure that personal information is encrypted. So no new devices will be supporting it, and everything has to move to BLE.

      It was quite a rich ecosystem of sensor devices, especially for cycling, including speed and cadence sensors, heart rate monitors, power meters, lights, radar, etc.

      It has been extremely popular over the last 20 years.

    • matsemann 31 minutes ago
      Ant+ is for connecting sensors and other stuff. Like heart rate monitor, power meter, control resistance on a trainer etc.
    • monknomo 56 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.
      • jeffbee 11 minutes ago
        It also got nuked from orbit by European regulators. The ecosystem has a huge installed base but no future.
  • Rebelgecko 20 minutes ago
    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

  • __mharrison__ 24 minutes ago
    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.

  • mholt 50 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. It might need a UV filter.

    That said, I don't love needing a separate device (hence, I don't own any bike computer). This is just my preference, but 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!

    EDIT: Woah, you got ANT+ support using BLE radio? I am not surprised that that is possible, but dang, that must have been a clever LLM.

    • robot_jesus 12 minutes ago
      To each their own and the e-ink computer is a neat project. But I'm personally with you on not wanting a separate device. I have my iPhone and a quad lock case I swap on for rides.

      Not sure I'm 100% on board with the visual style of your interface (some of the metrics look like they'd be nearly impossible to read while riding 30mph down a gravel road) but I'd love to check it out once it's released.

      Do you have a way to sign up for release email or updates for your project?

      Good luck!

  • seemaze 23 minutes ago
    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..
  • pilina 1 hour 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 1 hour ago
    Wow. You managed to receive ANT via BLE hardware?! I didn't know these two protocols were so similar.
    • stingrae 1 hour ago
      yes. they luckily the same phy, 1 Mbit/s GFSK modulation.
  • evrimoztamur 1 hour 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...
    • matsemann 29 minutes ago
      Garmin Edge 10X0 series is touch only (except for pause and lap button). Was a bit apprehensive myself moving to 1040 from my old 5X0 series with buttons only, but no issues in weather so far. More reliable than a phone display with droplets.
  • dinan 1 hour 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 1 hour 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 41 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.
    • orbital-decay 24 minutes ago
      For all their readability benefits under direct sunlight, prolonged exposure also damages or kills them. You need at least a UV blocker for outdoor use, but the heat cannot be avoided.
  • dumbmachine 1 hour ago
    Wow, this is really cool. I really needed something for my neo retro build, this might just fit the bill.
  • jeffbee 14 minutes ago
    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?

  • maxrev17 1 hour ago
    Insane! Quality on the ANT too!
  • memoryfault 54 minutes ago
    I love this. How do you house & secure your lily on your bike?
  • Lucasoato 1 hour ago
    Any open source GPS locator for bikes?
  • arpanghoshal07 1 hour ago
    great!