A PCB business card with a batteryless LED, powered by the phone that taps it (kevin.md)

61 pointsby thekevintang2 days ago19 comments

Neywiny 6 hours ago

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

taylorhou an hour ago

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

mahirsaid 44 minutes ago

2nd one this week on this site. must be a trend or something?

hexapus 5 hours ago

AI:DR

1shooner 4 hours ago

> Once you’ve felt that, you start seeing NFC taps differently. You’re not reading the tag. You’re powering it.

aselimov3 2 hours ago

I stopped at this line too. My AI detector is too bad right now

DANmode 4 hours ago

Your loss.

One of the best and most complete Hackaday posts I’ve ever read, lol.

Some stuff, it’s okay to let the robot do.

Finding and filling in a slick little BOM display component, for example: people don’t just come up with extra 30+ minutes to do that when they’re spending hours on a post.

aselimov3 2 hours ago

If I want to read a post about an NFC business card written by ChatGPT, I can ask it myself

bsder 2 hours ago

Without a repo link to design files, I have no evidence that this project is real and not marketing copy. Sorry.

I believe it's real, but there are no artifacts to corroborate. That's a poor article.

It is sad that the internet has devolved into this state.

Guvante 2 hours ago

They didn't even get a good photo of the final product...

The only shot I saw was "while I was writing them" why not show what it looks like while in use?

wolvoleo 2 hours ago

It's a great project, just sad the author fobbed off the blog post about it to AI and made it worse by doing that.

These days it's more important for a write-up to be real than to have snazzy wording. Especially to an audience interested in this kind of topic.

jppope 5 hours ago

one of the coolest things I've ever seen

chews 6 hours ago

at least https://news.ycombinator.com/item?id=49478426 shared a github.

fabioyy 5 hours ago

website is down

thekevintang 2 days ago

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.

gnabgib 6 hours ago

That made the post? Everything in your comment is in the post, AI summaries aren't very popular.

> I designed the whole board as code, which I’d recommend to anyone who, like me, finds dragging traces around with a mouse maddening. KiCad—the free PCB tool—has a Python API, so the entire card is generated by a script.

mzi an hour ago

My guess is that the whole project including the selection of chips was made by an AI.

willis936 5 hours ago

I can understand because I find MCAD drafting to be a chore and like that I can describe a script to generate geometry now for most things.

Even still, it's difficult for me to fully get it. There is so much art in ECAD layout. There are many dimensions to weigh and high levels of thought and care can result in a higher quality, lower cost product. Many nuances are not properly captured by simplistic automations or chatbots and won't be for some time. Things that accelerate schematic capture, layout capture, library management, and simulation are all useful tools. They're most effective when used with care and thoughtfulness.

King-Aaron 5 hours ago

> I still can't get over JLCPCB assembling ten of these for about $75.

I remember years and years ago I made some business cards out of 304 stainless with a laser etched design and bottle opener on the side (before that whole idea became mass marketed). It cost me over a hundred bucks for ten, wild that you can get whole pcb assembly done for less now days.