Show HN: I made open source, zero power PCB hackathon badges(github.com)
94 pointsby kaipereira19 hours ago5 comments
  • wiether37 minutes ago
    Not directly related to the submission content, but trying to monitor trends: I understand there's the "no capitalization" one at the start of sentences and for the "I".

    Apparently OP is not following this one, but I see that _some_ proper nouns are not capitalized (like github, singapore, overglade...) while others are.

    Should I update my userscript to handle an incoming new trend?

  • sen8 hours ago
    That's very cool.

    I have a few ePaper picture frames that don't use any power, and when you tap your phone to them it uses the power-over-NFC to boot itself and update the photo you send to it. It's such a cool idea and something I always felt like could be used more for displays that don't need to update very often.

    • larelli2 hours ago
      This sounds really neat. Is it a commercial product or did you build them yourself?
  • robertclaus10 hours ago
    How much did they end up costing? We do a similar PCB medallion every year for another event and haven't been able to get quite that fancy due to cost. We usually only manage to get some LEDs and a processor in our lower budget range.
    • kaipereira10 hours ago
      The total ended up being about $10/badge for 60 (5 for badge, 5 for eink), and we made the mistake of not ordering enough, so we ordered a couple more that were about $1 more expensive each. We bought all the badges from JLC and the prod files are in the repo if you want to see how much they come to in higher order quantity!
  • bschwindHN6 hours ago
    Very cool! Quick question: did you use a plugin to generate the NFC antenna?

    The routing and layout looks nice. The end result is great! I bet it was satisfying to get it working on the first try.

    • kaipereira6 hours ago
      I used https://eds.st.com/antenna/#/ to get an antenna that fit with a target inductance of 4.7uH and then used https://github.com/nideri/nfc_antenna_generator to create the footprint which I slightly modified for the board! You can read a bit more about it in the journal (JOURNAL.md)!

      It was really satisfying to get everything working (especially the NFC because I've found RF to be a bit tricky), but the eink logic was actually a bit of gamble, because I broke my only eink while prototyping so the production batch was the first test of the driver. So always carry spare components when designing prototypes!

  • NooneAtAll38 hours ago
    how does "zero-power" work exactly? all power from NFC?
    • kaipereira8 hours ago
      So the eink holds its state once it’s programmed so you do need an initial program of the badge through USB-C, and then the NFC uses passive RF harvesting.
    • cactacea8 hours ago
      yes NFC and with an e-ink display no battery needed from there