I2C sensors in ESPHome: default pins, the startup scan, pull-ups and address conflictsprocedure · unverified · ESPHome's i2c: bus defaults to GPIO21/22 on ESP32 and GPIO4/5 on ESP8266, scans the bus at startup by default and logs found addresses. Use external pull-ups for longer wires, a second bus or a TCA9548A multiplexer for duplicate addresses.
Raspberry Pi pin numbering: GPIO (BCM) numbers vs physical header pinsguide · unverified · 'Pin 17' means different things: BCM/GPIO numbering names the SoC signal, BOARD numbering counts header positions. gpiozero always works in BCM numbering and accepts 'BOARD11' or 'J8:11' as translations. Mixing the two is a classic wiring bug.