Hacker News Reader

Comment by latchkey | Hacker News Reader

I have a large project that uses qrcode stickers to identify hardware. I tried with barcodes and found that iOS doesn't scan them as quickly or easily.

Why do we use barcodes?

View on HN

There is a massive industry, sets of standards, and infrastructure relying upon barcodes. For example, anyone who does ships product to their partners as part of an EDI/X12 workflow utilizing advances shipping notifications, will need to be able to generate a UCC compliant shipping label.

Warehouse management systems, same story. In fact, in supply chain, QRCodes are extremely rare. All the portable "brick on a stick" wireless terminals rely upon barcodes.

Production workflow, where jobs move from station to station often rely on barcodes to identify jobs and components.

Not to mention the most obvious one: shopping. Cash register scanners don't do QRCode. They follow the UPC standard along with the entire retail industry. That's likely never going to change.

Hmm, a lot of the in-store imagers/readers are 2D capable now (eg: readers at HD and Kroger in USA). Not all, but when these facilities get a hardware refresh they get 2D - but still have nothing to read. Scanners have to be deployed first, then 2D can move to on-package

No, it's just not that simple. It's not a question of what readers are capable of. It's multiple universal standards that would have to change, and for what? Packaging has a bad enough time with UPS codes getting distorted to the point of being unreadable, and that would be even worse with 2D codes. Furthermore, 2D codes take longer to decode.

1D scanners are able to scan the entire surface of an object to find the codes quickly, or even two surfaces at the same time. Think cashiers again, quickly plowing through a cartload of merchandise. They don't have to aim to do that. They just have to know what side the barcode is on. It's a non-trivial engineering issue to make 2D as efficient to scan as 1D.

There is absolutely no reason to move to 2D codes for the majority of existing 2D applications.

It is simpler technology, just 1D.

You can read it with a led or laser, a motor with a mirror, a filter, a photodetector and a cheap microcontroller that cost cents.

The technology is so simple. A point of light moves and you get an output of ceros and ones, edges are supersharp.

There are lots of cheap chinese guns with the components already integrated.

If you have already a video camera and big microprocesor, QR are much better.Scanning barcodes with cameras is tricky, because barcodes edgess are blurry.

Professionals are going to use a gun anyway so it makes sense for them.

> Why do we use barcodes?

Barcode readers are cheaper.

Also, QR codes don’t work too well with damaged or faded paper. Think receipts. 1D barcodes work much better there as there’s redundancy in the second direction. Basically, QR codes do have the advantage in the density department, but are more complicated (relatively) to parse and more susceptible to damage. Tradeoffs that depend on your situation.

This just isn't true. QR codes have a high degree of redundancy built into them via error correcting codes. For example there is the famous case of a bitcoin private key being recovered from a small amount of a qr code and a blurry shot of the full one[0].

[0] https://www.freecodecamp.org/news/lets-enhance-how-we-found-...

I think the average QR code has what, 15-30% redundancy?

a 100 pixel high 1d barcode is 10,000% redundant in one axis :)

I found that if you damage one of the edges (with the positioning markers), most software will fail to read it.

My job involves scanning damaged codes of both types on a regular basis. QR codes are way more reliable than you'd expect, and will often scan even with partial codes, on damaged labels. Barcodes meanwhile always need a complete code to work.

Actually barcode readers are expensive. Barcode printers are cheap though.

[Edit] I misunderstood the context as being optical scan codes vs other technologies, not 2d vs 1d

Barcodes are easier and more reliably scanned by dedicated devices; QR codes are easier and more reliably scanned by general-purpose devices like phones.

I've used scores of different hardware readers (zebra, motorola, star, el-cheapo, etc). All of them read 2d faster than they read 1d. And we get a higher first-try success on 2d. IIRC 1d was like 80% and 2d was over 95%

There are many 1d standards. How many did you try?

C128(ABC) and 39 got the most testing (other players in my space like C128). I'd also like to add that the fail rate on C128 increased as the encoded values got complex. That is to say 15 numeric chars was "very reliable" but 17 alpha-numeric+1 symbol had was "very unreliable"

And if you're in the <12 digits only space C128 is still a safe choice

That's an interesting observation. I'd expect C128 to be good because the checksum character should reject most bad scans.

Yessir, that's my (perhaps unclear) point. Give it the trigger on the "complex" C128 and we get a read fail. But scan success on attempt 3 or 4. QR scans with high success on first bread.

Does QR include some kind of error correction code? That would be far more sophisticated than a checksum, and lead to more salvageable results from bad scans.

Reply on news.ycombinator.com