alt Hacker NewsA PCB business card with a batteryless LED, powered by the phone that taps it
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is it possible to do this with a wearable? say jewelry? i've been fascinated with the whole digital to physical world dislocation and this inspires me to dust off an old idea of around the world "collecting" passport stamps but the only way to actually collect them is by a physical tap. similarly, i can see jewelry that lights up upon being tapped by a phone or together. fun
2nd one this week on this site. must be a trend or something?
one of the coolest things I've ever seen
at least https://news.ycombinator.com/item?id=49478426 shared a github.
website is down
Author here. One thing that didn't make it into the post: there are no hand-drawn traces on this board. I find mouse-driven PCB layout maddening, so the whole card is a Python script driving KiCad's API—antenna coil, lettering, everything. Retuning the antenna meant changing one number and re-running the script, which as a hardware novice was the difference between finishing this and giving up.
The chip is NXP's NTAG I2C Plus. I picked it for the energy-harvest pin (that's what lights the LED) and only realized later that it ships without NDEF formatting—which is why every consumer NFC app refused to touch it. Sending it raw write commands through Core NFC turned out to be much less scary than I expected: the part that matters is about 60 lines of Swift.
I still can't get over JLCPCB assembling ten of these for about $75.
We just did this https://news.ycombinator.com/item?id=49478426 this is starting to become the risc v of fpga resumes. It's certainly work and making anything that exists and works even somewhat is commendable but it's getting played out