标签：#ha

You scan one to pay at a sari-sari store, pull up a restaurant menu, or board a flight. The QR code has quietly become one of the most universal pieces of interface design on the planet. But it was never meant for any of that. The QR code was invented in 1994 to solve a very specific problem on a Japanese car factory floor, and the engineering decisions made under that constraint are exactly why it later conquered the world. A barcode problem on the assembly line In the early 1990s, Toyota's manufacturing arm had a data problem. Tracking thousands of distinct components through production meant scanning barcodes, and barcodes are stingy: a standard one-dimensional barcode holds roughly 20 characters. Workers were ending up with parts plastered in ten or more barcodes just to encode enough information, and each one had to be scanned separately. It was slow, and on an assembly line, slow is expensive. Masahiro Hara, an engineer at Denso Wave, a Toyota subsidiary, took on the challenge of designing something better. He wanted a code that could hold far more data, be read much faster, and tolerate the dirt, smudges, and odd angles of a real factory rather than a clean lab. Designing for speed and any angle The breakthrough was going two-dimensional. By encoding data in a grid of black and white squares rather than a single row of lines, Hara's team could pack in thousands of characters instead of a few dozen. The name they chose, QR for "Quick Response," was a direct promise about scanning speed. The most recognizable feature of a QR code, the three large squares in its corners, solves the hardest part of the problem: letting a scanner instantly find the code and work out its orientation no matter how the part is turned. Hara's team analyzed printed material to find a black-and-white sequence that almost never occurs naturally in text and images, and settled on a ratio of 1:1:3:1:1 for those corner markers. Because that pattern is so rare in everyday print, a scanner ca

Quoting from an email they sent: Hi Fabian, In May, we sent you an email announcing that starting today, the Claude Agent SDK, claude -p, and third-party apps built on the Agent SDK would stop drawing from subscription rate limits and move to a dedicated monthly credit. We're writing to let you know that we’re not making this change today. We’re working to update the plan to better support how users build with Claude subscriptions. What this means for you Nothing changes for now. Agent SDK, clau

Hi! me and my friends together built an 8 bit CPU implemented in Logisim purely from scratch. The control unit of this system does not implement the generic microcode ROM or any kind of RAM. This was made purely from discrete logic gates and coded the system to run different programs. key features: Custom 16-instruction Harvard ISA, 8-bit fixed format, 4 general purpose registers Hardwired control unit built entirely from AND/OR gate logic matrix Dual-phase clocking to eliminate race conditions