Configure KC868-A8 in ESPHome

[admin]

i think maybe you can't connect directly by digital input of A8, because A8's digital input use by PCF8574 IIC extend chip, so i asked you what your water pulse sensor's speed, PCF8574 refresh input port need time.
you can try to connect with these ports:
DS18B20/DHT11/DHT21/LED strip -1: GPIO14
DS18B20/DHT11/DHT21/LED strip -2: GPIO13
DS18B20/DHT11/DHT21/LED strip -2: GPIO32
DS18B20/DHT11/DHT21/LED strip -2: GPIO33

such as connect with GPIO14, it's connect with ESP32 pin directly, just have a pull up resistance.