April 19, 2026

Swipe cards? Nah—swipe the comments

Reading Input from an USB RFID Card Reader

Cool hack, but the crowd wants the model number—now

TLDR: A dev shares Go code to capture exclusive input from a USB RFID keyboard using a Linux trick. Top reaction: “Which reader is it?”—the missing model is the drama, because people want a plug-and-scan gadget they can actually buy.

A tinkerer shows how to tame a budget RFID card reader that pretends to be a keyboard, so card swipes don’t spam your entire computer. The trick: a Linux-only switch that gives one app exclusive access, and some tidy Go code to print the card number when you scan. It’s clean, it’s useful, and the author even side-eyes “fluffy Python” while name-dropping a Python example for the same job.

But the audience had one big vibe: name the gadget. The top—and basically only—comment roared what everyone’s thinking: which RFID reader is this? The irony wasn’t lost on readers; the post’s section called “The Name of the Beast” explained the Linux spell, not the actual device. Cue the running gag: great code, mystery hardware. People want a keyboard-style reader—the kind that types numbers into any app—so they can buy the exact thing and follow along.

Mini-drama alert: the gentle jab at Python vs. Go sprinkled a little language-war seasoning, even if no one swung chairs—yet. Bottom line: the guide nails the “don’t-type-everywhere” problem and shows where to find the device path, but the missing make-and-model is the cliffhanger keeping everyone refreshing the comments.

Key Points

  • USB RFID readers can appear as keyboards and send scans as keystrokes to focused applications.
  • Exclusive access to such devices on Linux can be achieved via the EVIOCGRAB ioctl.
  • The article provides a Go program that opens the device, applies EVIOCGRAB, and reads input events.
  • Device discovery is done via /dev/input/by-id to locate the correct event-kbd device.
  • The code maps key codes to characters and prints the RFID value upon Enter key detection.

Hottest takes

“they don’t specify which reader the entire article is about” — ranger_danger
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