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Comment by semireg | Hacker News Reader

I bought a hundred different label printers off eBay/amazon so I could reverse engineer and test all the different protocols. Now my app works with most label printers on the market and manufacturer’s send new models to me without even asking.

I personally answer every support email. My wife once asked me how many customers I had. Then she asked how many email support emails I’ve handled over the same time period. They were about equal (5 figures over 5 years)!

https://label.live/

Edit: on second thought, maybe I did things that DID scale. Hmm…

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Do you have a hilarious test suite that physically prints 30 complex designs to ensure things are ostensibly working? Do you have a room with dozens of the printers live at a given time?

Yes, I have a room with 100 label printers. They aren’t powered on. If I make changes to the built-in driver then yes, I take out the printers and make sure they function as expected. The way my app works is by sending raster images to the printers (vs explicit commands for text, barcode, line, etc). Because of this, much of the pixel-perfect testing can happen via PDF generation, which is the other core feature of Label LIVE - submitting PDFs to operating system printers (drivers), or generating and saving PNGs/PDFs to the file system.

I imagine a giant knife switch on the wall outside the room, to power up all the label printers at once while you're safely outside wearing a lead apron.

I once visited a HP site in Italy where they had hundreds of inkjet printers on racks running tests. I think it was reliability testing rather than software.

Interestingly, and perhaps ironically, Label LIVE is used by FAANG to print labels for their mobile testing labs where hundreds of mobile devices run their apps on real hardware, server racks, super computing clusters, and labeling prototypes.

Cries with the demise of the original Symbol. (It's owned by Zebra now.)

A giant university student housing department changed their FMMS system from Apple Newton MessagePad 130 from Symbol MC50's in the spirt of Barcodes and database for all the things! In that era, I had ~50 unique smart PDA-barcode scanners on my desk.

Wow. I didn’t know this history. Poor MessagePad… Eat up Martha!

It was one of the last known large-scale users. They were pretty durable and it was needed as they were used outside and in spaces with humidity, dirt, etc.

The final contenders came down to the MC9000, MC50, and MC430. The MC9000 was "too expensive" despite meeting all of the requirements, so the MC50 was chosen.

PS: I acquired an eMate 300 because it's quirky and interesting.

>My wife once asked me how many customers I had. Then she asked how many email support emails I’ve handled over the same time period. They were about equal

That's similar to me. Roughly the same amount of support emails and customer orders. The funny thing is when I looked deeper most people raising support issues didn't buy and most people who bought never raised a support issue.

On the subject of label printers one of the things I'm looking forward to in retirement is never touching a printer driver for a label or receipt printer again. They caused me so much aggravation.

True story in the asymmetry of support vs sales. My “best customers” are the people who google for a solution, download, it works, and they buy a license. Done and done.

How long did each reverse engineering take you? This seems like something that would require scale, so well done.

An hour to a few days. Sometimes a week of back and forth to 1) make it work, 2) make it work right, and 3) make it work fast.

Many times there’s a PDF for the printer “language.” Think ZPL or TSPL. But even then, each printer has quirks (two incompatible settings) or a setting that’s unitless (dots? mm?) and the best way to nail it down is by using a USB sniffer, capturing the commands, and then implementing similar custom controls and logic in the app.

Amazing!! Now I want a label printer just to test this.

Barcode apps and libraries that render and scan can do the same without consumables.

True story. You can play with the app by downloading and installing. By default it generates PDFs.

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