Water level monitor using open-source microcontrollers (Arduino, ESP8266, ESP32) and ultrasonic sensors HC-SR04 / JSN-SR04T / or TOF laser sensors VL53L1X / VL53L0X. Arduino Core & ESP-IDF implementations. For ESP32 available also with FreeRTOS. ESP8266 and ESP32 support for Ultra Low Power deep sleep app. ESP32 available with PHY Ethernet LAN8720