Waveshare RP2040-Zero, GPIO26 water NTC and GPIO27 case-air NTC. Each 10k NTC goes from ADC pin to ground, with an individual 10k pull-up to 3V3. Build with the included GitHub Actions workflow; download UF2 from its artifacts. Experimental only. This emulates a third-party USB VID/PID for local compatibility research. Linux hwmon binding and temperature accuracy are NOT verified. Do not rely on it for fan safety. Keep existing cooling control enabled. Thermistor beta 3950 is provisional. GPIO26 and GPIO27 are small board pads.