A02YYUW Waterproof Ultrasonic Sensor for Arduino / ESP32 / Home Assistant (IP67, 3~450cm, UART)

The A02YYUW is an IP67-rated waterproof ultrasonic distance sensor designed for reliable ranging between 3 cm and 450 cm. Featuring an ultra-short 3 cm blind spot and a 3.3V to 5V UART interface, it is ideal for makers and home automators monitoring water tanks or building outdoor proximity systems. It connects directly to Arduino, ESP32, and Raspberry Pi platforms, with native support in ESPHome for Home Assistant.

Native ESPHome and Home Assistant integration

The sensor features official support in ESPHome for this UART variant, allowing you to pull real-time distance metrics straight into Home Assistant without writing custom C++ code. Applying a sliding window moving average filter in your YAML configuration easily smooths the serial data stream for rock-solid automations.

Sealed IP67 waterproof construction

Unlike sensors with exposed circuit boards, this module features a fully sealed, integrated housing that resists dust, splashing, and temporary submersion. This durable design ensures long-term operational stability in harsh, humid environments across temperatures ranging from -15°C to 60°C.

Ultra-short 3cm blind spot

While traditional waterproof ultrasonic sensors have dead zones of up to 20 cm, the A02YYUW reduces the blind spot to just 3 cm. This enables precise liquid level measurement right to the top of tanks and reservoirs, helping prevent overflow in automated pumping systems.

Wide 60-degree detection cone

The acoustic transducer operates with a 60-degree reference angle, providing consistent target reflection with a 100 ms response time and ±1 cm measurement accuracy. The sensor delivers a fine 1 mm resolution across its entire 3 cm to 450 cm operational range.

Simple UART microcontroller interfacing

Running on 3.3V to 5V power with an average current draw of 8 mA or less, the sensor communicates via a standard 9600 bps UART serial link. It includes a PH2.0-4P connector cable for quick plug-and-play wiring to popular microcontrollers.

Versatile liquid and level sensing

Thanks to its weatherproofing and low power requirements, the module is well-suited for smart plant watering systems, rain barrel monitors, aquarium auto top-off units, and smart bin capacity detectors.

Downloads & documentation

• Product wiki (DFRobot)