Show HN: I made open source, zero power PCB hackathon badges
github.comI love getting cool swag from hackathons and I also love designing PCB's, so when my friend asked me if I would design hackathon badges for a large game jam in singapore, I was absolutely down!
The theme of overglade was a "The game jam within a game", pretty cool concept right! High schoolers from around the world were flown out to the event by hackclub after they spent about 70 hours designing their own game.
These badges needed to be really cheap and simple, because we were going to manufacture about a hundred in a pretty limited amount of time. I went with a zero-power approach, which means sticking with e-inks, and I decided to include NFC if the organizers wanted to introduce it into the roleplay of the event, and so participants could add their website or github if they so choose!
I used an RP2040-based architecture because it's really easy and cheap to get on the first try, and then added an ST25 passive NFC tag which was really simple to configure. The badge is in the shape of a ticket, because you got a "ticket" to the event after spending a lot of time designing games to qualify! 20 GPIO's are broken out onto the edges if you're ever in a pinch at a hackathon, and I wanted the badges to feel really fun so there's a lot of art designed by various people in the community!
The badge worked really well and I learned quite a lot in the process. My takeaways are to manufacture a BUNCH of extra badges, because some will end up breaking; to think about your PCB in 3D, because one of the inductors was a bit tall and caused more badges to break; and to have a strong vision of your final product, because it really helped me to create something unique and beautiful :D
I like to journal about all my projects, so if you'd like to read my full design process, feel free to take a look at my journal (https://github.com/KaiPereira/Overglade-Badges/blob/master/J...). If you also have any questions or feedback, I'd be happy to answer them! 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. This sounds really neat. Is it a commercial product or did you build them yourself? This is so cool. Could you share more about where I could find them? 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. 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! Interesting... RP2040 seems like maybe a bit overkill for a zero power badge. I've participated in writing some software for an RP2040 powered badge for the RVASEC conference in Richmond, VA, for several years, and the RP2040 is really nice to program for, and is quite powerful. https://www.youtube.com/watch?v=A5ZrHAXCFLA Yeah the RP2040 is a bit overkill, but it's really cheap to get from JLC, easy to prototype FAST and easy if anyone wants to reference the design and create/program their own badges. I have been looking at some other MCU's like the CH32 for future projects, so if you also have any suggestions for other ones, I'd love to hear them! how does "zero-power" work exactly? all power from NFC? 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. yes NFC and with an e-ink display no battery needed from there 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. 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! Awesome resources, thanks so much! Went to Treehacks at Stanford this Feb and they had PCB badges too! Gotta say these ones are much cooler tho :D Thanks so much! Do you ship internationally, also with complete setup of the hardware? We ordered the PCB's and badges separately, but it's extremely easy to assemble, you just attach the eink on using the FPC connector and the badges are already in a complete setup of the hardware if you get PCBA. You can make it more fun on yourself if you want to assemble them by hand and it's probably a bit cheaper, and JLC will ship to pretty much anywhere in the world. 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?