Does the DFRobot A02YYUW work with 3.3V boards like the ESP32?

Yes, the DFRobot A02YYUW Waterproof Ultrasonic Sensor operates flawlessly on a 3.3V to 5V power supply. This means you can wire its UART TX and RX pins directly to 3.3V microcontrollers like the ESP32 or Raspberry Pi without needing a logic level converter.

Is the A02YYUW better than the JSN-SR04T ultrasonic sensor?

Yes, the A02YYUW Ultrasonic Sensor is significantly better for close-range measurements than the JSN-SR04T. While the JSN-SR04T has a massive 20cm blind spot, the A02YYUW features an ultra-small 3cm blind spot, allowing you to accurately measure liquid levels even when a tank is almost completely full.

How do I smooth out the UART data in Home Assistant?

To smooth out the data from the A02YYUW Ultrasonic Sensor in Home Assistant, you should use ESPHome's built-in sensor filters. Applying a filter like `sliding_window_moving_average` in your YAML configuration will average out the rapid UART readings and provide a stable, clean distance metric on your dashboard.

Can I get technical advice for my DIY IoT project in Hong Kong?

Absolutely! Sun Cheong Computer Co. Ltd. encourages makers to build and experiment. You can bring your ESP32 board and project ideas to our Sham Shui Po physical store, and our technical staff will help you wire the A02YYUW sensor and provide advice on your ESPHome setup.

Can this sensor measure the depth of highly corrosive liquids?

While the DFRobot A02YYUW Ultrasonic Sensor is IP67 waterproof and handles water and humidity perfectly, it is not designed to be submerged in or exposed to highly corrosive chemicals or strong acids, which could eventually degrade the sealed casing.

DFRobot A02YYUW Waterproof Ultrasonic Sensor

Name: DFRobot A02YYUW Waterproof Ultrasonic Sensor | UART
Brand: DFRobot
SKU: 21PS002310
Price: 709.0 TWD
Availability: InStock

Short Product Description

Building a reliable liquid level monitor or outdoor proximity system? The DFRobot A02YYUW Waterproof Ultrasonic Sensor delivers precise distance measurements from 3cm to 450cm with an IP67 enclosed design that survives harsh, humid environments. Operating on a 3.3V-5V logic level with a standard UART interface, it connects seamlessly to Arduino, ESP32, and Raspberry Pi. It even features native ESPHome support for effortless Home Assistant integration! Need technical advice for your DIY IoT project? 新昌電腦有限公司 (Sun Cheong Computer Co. Ltd.) has over 20 years of electronic component expertise. Visit our Sham Shui Po physical store for instant pickup and expert DIY guidance!

Key Features

IP67 Waterproof Enclosure: The fully sealed body protects the internal circuitry from moisture, dust, and splashes, ensuring long-term outdoor stability.
3cm Ultra-Small Blind Spot: Outperforms traditional waterproof sensors by measuring distances as close as 3cm, perfect for full-tank detection.
Native ESPHome Support: The UART interface is officially supported by ESPHome, making Home Assistant integration incredibly simple.
Wide 3.3V-5V Compatibility: Operates safely on both 3.3V and 5V logic levels, allowing direct connection to ESP32, Arduino, and Raspberry Pi boards.
High Precision Ranging: Delivers accurate distance readings from 3cm up to 450cm with a precise ±1cm measurement accuracy.
Instant Store Pickup: Don't wait for shipping when you are mid-build; grab your IoT sensors instantly at our Sham Shui Po retail location.

Full Product Description

The Ultimate IP67 Distance Sensor for Harsh Environments

The DFRobot A02YYUW Waterproof Ultrasonic Sensor provides highly stable and accurate distance measurements in environments where standard exposed sensors fail. Standard ultrasonic modules like the HC-SR04 quickly short-circuit in high humidity or dusty conditions. By utilizing a fully sealed, integrated IP67 waterproof body, the A02YYUW sensor withstands dust, splashes, and temporary submersion, making it the perfect choice for outdoor proximity detection and continuous liquid level monitoring in water tanks.

Overcome the 3cm Ultra-Small Blind Spot Limitation

The DFRobot A02YYUW Ultrasonic Sensor solves the massive dead-zone problem found in older waterproof modules by offering an industry-leading 3cm blind spot. Competing split-design sensors, such as the JSN-SR04T, suffer from a 20cm blind spot, making it impossible to detect when a water tank is nearly full. With the A02YYUW, you get precise 1mm resolution readings right up to the top of the container, preventing overflows and ensuring precise control in automated systems.

Native ESPHome & Home Assistant Integration

The DFRobot A02YYUW UART Ultrasonic Sensor eliminates the need for complex C++ coding by offering native platform support in ESPHome. Because this specific UART version is officially supported by the ESPHome component, DIY smart home enthusiasts can easily pull real-time water level metrics directly into their Home Assistant dashboards. Simply pair it with a low-power IoT board like the FireBeetle 2 ESP32-C6, and your custom sump pump monitor will be up and running in minutes.

💡 Pro Tip from Our Technicians

"When integrating the DFRobot A02YYUW Waterproof Ultrasonic Sensor into Home Assistant, you might notice the raw data fluctuates slightly! Because the UART bus outputs data multiple times per second, we highly recommend applying Sensor Filters (such as sliding_window_moving_average) in your ESPHome YAML configuration to smooth out the readings. Also, ensure the sensor is mounted perfectly perpendicular to the water surface for the best acoustic reflection. If you are building a DIY rain barrel tracker and need help with your ESP32 wiring or ESPHome code, drop by our Sham Shui Po store! Our team at 新昌電腦有限公司 (Sun Cheong Computer Co. Ltd.) loves helping makers debug their smart home circuits."

Technical Specifications

Product Type: Waterproof Ultrasonic Distance Sensor
Model: A02YYUW
Working Voltage: 3.3V - 5V DC
Average Current: ≤ 8mA
Detection Range: 3 cm - 450 cm
Blind Spot Distance: 3 cm
Output Interface: UART Serial Port (9600 bps)
Response Time: 100 ms
Measurement Accuracy: ±1 cm
Reference Angle: 60°
Waterproof Level: IP67
Operating Temperature: -15°C to 60°C
Package Includes: 1x A02YYUW Sensor, 1x PH2.0-4P Connector Cable

Delivery Options

Local delivery within Hong Kong and in-store pickup.
Free shipping for orders of HK$400 or above; HK$35 shipping fee for orders below HK$400.
Shipped by SF Express, usually dispatched the same day for orders confirmed before 6:00 PM (Mon–Sat).
Estimated delivery time: 1–3 business days after dispatch (Hong Kong).
In-store pickup details (location and time) will be confirmed by email or phone message.
Delivery times are estimates and may be affected by weather or unforeseen circumstances.

FAQ Section

Does the DFRobot A02YYUW work with 3.3V boards like the ESP32?Yes, the DFRobot A02YYUW Waterproof Ultrasonic Sensor operates flawlessly on a 3.3V to 5V power supply. This means you can wire its UART TX and RX pins directly to 3.3V microcontrollers like the ESP32 or Raspberry Pi without needing a logic level converter.
Is the A02YYUW better than the JSN-SR04T ultrasonic sensor?Yes, the A02YYUW Ultrasonic Sensor is significantly better for close-range measurements than the JSN-SR04T. While the JSN-SR04T has a massive 20cm blind spot, the A02YYUW features an ultra-small 3cm blind spot, allowing you to accurately measure liquid levels even when a tank is almost completely full.
How do I smooth out the UART data in Home Assistant?To smooth out the data from the A02YYUW Ultrasonic Sensor in Home Assistant, you should use ESPHome's built-in sensor filters. Applying a filter like sliding_window_moving_average in your YAML configuration will average out the rapid UART readings and provide a stable, clean distance metric on your dashboard.
Can I get technical advice for my DIY IoT project in Hong Kong?Absolutely! Sun Cheong Computer Co. Ltd. encourages makers to build and experiment. You can bring your ESP32 board and project ideas to our Sham Shui Po physical store, and our technical staff will help you wire the A02YYUW sensor and provide advice on your ESPHome setup.
Can this sensor measure the depth of highly corrosive liquids?While the DFRobot A02YYUW Ultrasonic Sensor is IP67 waterproof and handles water and humidity perfectly, it is not designed to be submerged in or exposed to highly corrosive chemicals or strong acids, which could eventually degrade the sealed casing.

Target Users / Applications

Smart Home Enthusiasts: Integrating native ESPHome water level monitoring into Home Assistant to track rain barrel reserves or sump pump activity.
Aquarium & Hydroponics Hobbyists: Creating automated auto top-off (ATO) systems that require precise 3cm blind-spot detection to prevent fish tank overflows.
Smart Agriculture Developers: Building outdoor, weather-resistant IoT nodes to monitor irrigation tank levels using ESP32 and LoRaWAN boards.