QR scan difficulty · measured
Not every phone reads the same QR codes.
The QR code was invented for messy factories
In 1994, Denso, a Toyota-group parts maker, made the QR code for its factory floors. A barcode held about 20 characters, so workers scanned about ten for each product. “It was more like a job to read the barcode than to make the product,” recalls Masahiro Hara, who led the work. And “if the barcodes were contaminated with oil, they would become unreadable.”
So the new code had to “hold up against oil and grime.” It repairs itself: its error correction, the kind used on music CDs, restores the content even when up to 30% of the code is dirty or damaged. Hara credits the factory on site: “If I had been involved in code development at an IT company, I would not have successfully created the QR Code.”
More than a billion phones read fewer codes than an iPhone
On every iPhone, the Camera reads codes with Apple’s scanner. On Android, the Camera and QR button mostly open the maker’s own scanner, such as Samsung’s or Huawei’s Scan Kit; on Pixel, the QR button opens Google’s ML Kit. Google’s scanner also comes with Google Play services, so apps on most Android phones can use it; WhatsApp and Instagram carry it.
The gap opens on harder codes
Each row is one set of codes, and each mark one scanner. The band, and the number at the right, span the Android scanners.