A basement dehumidifier whose built-in control restarts the compressor within 30 seconds of finishing a cycle. Two ESP boxes replace that with a wide, adjustable deadband and an anti-short-cycle timer — no Home Assistant, no cloud. Now with a third, router-free config pair for buildings with no Wi-Fi at all.

Wiegand data lines idle at 5V, and the ESP32 is not 5V-tolerant. You don’t need a level-shifter IC or a resistor divider — a single signal diode does the job, and it does it better.

MicroPython rewrite of the Impression 5 giant calculator — 9-digit NeoPixel 7-segment display with 20 physical buttons, running on ESP32 or Raspberry Pi Pico.

ESP32 ESPHome device that monitors a Carrier furnace — reads a differential pressure sensor for filter restriction and a phototransistor to decode blink error codes from the status LED.

ESPHome config for a Wiegand keypad reader built on a thin-edge philosophy — the device only captures input and relays it to Home Assistant. Now folded directly into the garage’s RATGDO board instead of running on its own standalone ESP32.