Join the discussion
Write your take first — we'll ask for email only when you're ready to publish.
- Hacker News
- I once sent a letter to a friend with a hand-written QR Code whose content was the typed letter.
It's cool for the receiver, but tedious for the sender (but it's a good way to help with difficult to read cursive).
by jiehong - Anyone else scan their random junk that has QR codes to see where it goes? I've found a fair number of stuff has codes that do nothing. Bought an extra garage door opener remote, qr code on it does nothing. Got some SwitchBot gear, qr codes do absolutely nothing.by zf00002
- They likely encode not URLs for the public, but internal identifiers that are only useful internally.by rossant
- >qr code on it does nothing
It's like in the 2000s when you opened an .exe and nothing seemed to happen ... bad news.
by moralestapia - I used to in the mid 2000s but they kinda lost their magic for me at some point. They briefly regained the magic when I realized I could encode arbitrary text and make my own, but then I had so much trouble scanning the giant QR code I made (from printer paper) that the magic was gone again.by opan
- I work in hardware manufacturing. Our PCBs have QR codes both on the silkscreen and on stickers, but they don't encode websites. Rather, they are part numbers and serial/lot numbers for traceability and to assist manufacturing/inventory. Unless you know our (and our upstream manufacturers') specific patterns, they'll be irrelevant to you.
- QR codes were invented for inventorying and labeling. Sending links to your phone is a side effect.by thesuitonym
- QR codes, like other barcodes, store information. They never "do" anything.
Or are you saying the ones you found failed to checksum?
by kqr - That’s fun. I also love QR codes so I created https://qr-mailbox.com it gives u a we based inbox which just a unique string that lets you receive messages. I thought since Covid qrs have become a thing and ppl know how to scan and messageby hmontazeri
- I've really enjoyed reading the Grid World piece linked at the bottom of the post: https://alex.miller.garden/grid-world/by jdranczewski
- > Note that a lovely reader informed me shortly after publication that indeed I can include my full domain name in a version 1 QR code by using all capital letters instead of lowercase. TIL that the "alphanumeric" character set for QR codes actually contains symbols for URLs like : and /.
This is a nice trick worth remembering. I have used it myself in the past. Handy not just for creating ultra small QR codes, but also for getting as much data as possible into the limits of the largest QR codes.
by p0se1d0n - I hand drew this on a whiteboard. It was a lot more work than I anticipated.
- By the way, I also coded a QR symbol generator in PDP-10 assembly language.
- I saw similar engraved and then inked onto wooden boards at a restaurant, sadly, despite the error handling, 3 out of 4 I tried were not scannable, the 1 I did manage to scan to me to a reviews site for the restaurant (where a lot of reviews said they struggled to make the QR work - likely not the feedback the restaurant wanted)! I guess it kept me entertained whilst waiting for the bill.by scraft
- yea - as nice as they can look, many scanners expect very high contrast and a clear, unbroken bright border around the whole thing (many stylized ones I see lack a border). lacking either will mean many failures.by Groxx
- There was a tweet a while back where I guy was riding a train in China and took a photo of the QR code for his seat. He mentioned that you can use the QR code to order food and drinks delivered directly to you.
About 5 minutes later there was another tweet from him where:
- someone saw the original tweet (Guy 2)
- scanned the QR code
- ordered the OP a drink
- added a note to the order saying it was from Guy 2
Always loved this story.
by alexpotato - This is cool but I sort of hoped they were going to encode it and calculate the pattern by hand. I wonder how long that would take.by pimlottc
- If someone needs a gift idea:
I used something like this on a large sheet and cut it into pieces for a puzzle gift to a website where people left comments. Nowadays even easier to generate nice temporary websites for such things.
- I’m picturing an acrylic version of it, or even some other fancier material.
The starter kit: a 21×21 board, with three 8×8 finder patterns, two 1×5 timing patterns, and 120 white and 119 black modules.
The Version 2 expansion pack includes a 25×25 board, two 1×4 timing patterns, one 5×5 alignment pattern, 76 white modules and 75 black modules.
And so on.
(I dunno about the desired ratio of individual black and white modules. I gather the general idea is to balance black and white, but does that include or exclude the fixed parts, where black is somewhat more common? Finder pattern is 33∶31 black∶white, alignment pattern is 17∶8, 1×5 timing pattern is 3∶2, 1×4 timing pattern is 2∶2.)
by chrismorgan - > (besides micro QR codes)
In case anyone else is interested: https://en.wikipedia.org/wiki/Rectangular_Micro_QR_Code
by thih9 - this makes me wonder if there is an `infinite` version of QR Code that can be streamed from a printer (well, I guess things can be chunked).by jiehong
- Rectangular Micro QR Codes are not ordinary Micro QR Codes.by p0se1d0n
- No, I don't think that's it! That's a "Rectangular Micro QR Code".
I think it's this: https://www.qrcode.com/en/codes/microqr.html
by Wowfunhappy - I feel like Meshtag[1] was built for exactly this. The trick is that the symbol doesn't encode the link the way a QR code does -- it just references one on their server, so the drawing can be loose and imperfect and still resolve. The flipside is of course that if Meshtag ever shuts down, every tag in the world goes dead.by sssilver
- This is a unique approach, I’ve never heard of this. Shame it seems to be not downloadable in my region.by towers
- That's the same as MS Tag (dead). Anything which involves an online lookup is always going to suffer from a single-point-of-failure.
QR Codes work even if the publisher shuts down.
by edent - From the update: "Why are QR Codes with capital letters smaller than QR codes with lower-case letters?" https://shkspr.mobi/blog/2025/02/why-are-qr-codes-with-capit... (https://news.ycombinator.com/item?id=43149077)by keane