Dell XPS 15 7590 Fingerprint Reader on Linux: Goodix 27c6:5395
How I used OpenAI Codex to get the Goodix 27c6:5395 fingerprint reader working on a Dell XPS 15 7590 with Omarchy and Arch Linux.
Writing
HireFlow: keeping the hiring workflow clear
A position board, candidate context, and traceable team decisions in a compact private application.
The field around an interdigitated sensor
An electrostatic model of the electrode geometry used in my capacitive-sensor research.
Cooling and warming a capacitive ice sensor
Temperature and oscillator measurements from the January 2–3, 2026 experiments.
A thermocouple reader on Raspberry Pi Pico
MAX31855 decoding, Pico wiring, and a serial command for entering the USB bootloader.
A sensor oscillator in ngspice
The timing calculation and simulation of a Schmitt-trigger RC oscillator for capacitive sensing.
Reading a MAX31855 thermocouple with Rust on ESP32
Decoding a four-byte SPI response and adding temperature to an oscillator measurement loop.
ESP32 Rust setup on macOS: build, flash, and read serial output
Toolchain setup and the espflash 4.3.0 workaround used with an ESP32-D0WD-V3.
Measuring a signal period on ESP32 with Rust
A polling frequency meter: edge timing, timeouts, averaging, and the limits of a loopback test.
Where a Node.js API spends its time
Request timing, database pools, caching, and what changes when an API runs in several processes.
React hooks: state, effects, and stale results
Working through derived state, effect cleanup, and when memoization helps.
A first classifier, with a test set
A small scikit-learn example, followed by the evaluation mistakes that can make a good score misleading.
Code that is easier to change
Notes on naming, validation, types, and the cost of splitting code into smaller pieces.