#Android
Labels Printing Off-Center? Calibrate the Print Offset Once
After getting the label printer to fire its printhead, the next problem was that the text missed the sticker. I stopped guessing and printed rulers and corner markers to measure it, then clearly separated paper size, printable area, and offset into three distinct values.
Mapping a Building by Phone and Finding True North with GNSS
ARCore gives room-corner coordinates in meters accurately enough to use, but its world frame has an unknown orientation, so the resulting plan is always rotated by some angle. The fix is to collect pairs of (AR position, GNSS reading) while working, then fit a rotation using weighted 2D Kabsch, with weights based on each fix's accuracy, to find both north and the origin's coordinates.
Decoding a Bluetooth Label Printer Protocol from btsnoop
My Bluetooth label printer only had a mobile app and no way to connect it to my own system, so I enabled HCI snoop logging on my own phone, peeled away HCI/ACL/L2CAP/RFCOMM one layer at a time with a short Python parser, and compared the results with open-source libraries until I could read the commands and print directly from a script.
Android Dev on MIUI/HyperOS — adb Traps on Windows
adb is not broken, but Git Bash mangles /sdcard paths, PowerShell produces 0-byte screenshots, MIUI/HyperOS blocks the first installation, and here-strings swallow backslashes when generating PHP code — real traps I hit while developing an Android app on Windows, with commands that actually work