The graphic from README.md that shows the wiring uses a wrong pin number for the right (blue) sensor wiring. The graphic (and the config.yaml) refer to the pin as GPIO21, but according to https://www.raspberrypi.org/documentation/usage/gpio/ the pin used in the graphic is GPIO27.
The graphic from README.md that shows the wiring uses a wrong pin number for the right (blue) sensor wiring. The graphic (and the config.yaml) refer to the pin as GPIO21, but according to https://www.raspberrypi.org/documentation/usage/gpio/ the pin used in the graphic is GPIO27.