A02YYUW distance sensor not working
Mark.Olson 2026-06-12 05:26:03 219 Views1 Replies I purchased the A02YYUW Waterproof Ultrasonic Sensor with the Intention of wiring It to an esp32 and Integrating with espHome/Home Assistant. No matter what I try, though, I only check checksum errors In the espHome logs along with an occasional wild distance reading. With the help of chatgpt, I have tried every permutation of wiring the blue and green wires to RX, TX, P16, and P17. I have read all your documentation very carefully but nothing works. Multiple AI models have told me after 6+ hours of troubleshooting that the sensor Is bad. Chatgpt just said, "The ESP32 is receiving UART traffic, but the traffic is corrupt. Conclusion: replace the sensor/harness. The ESP32, Wi-Fi, YAML, UART component, power level, and mode-line tests are no longer the likely cause."
I really really need this to work asap, but I hate to send it back without knowing the root cause problem. Any ideas or suggestions?
Also I notice that the sensor itself is labeled “A0221AU” not “A02YYUW”. Everything I read online suggests they are close cousins but there can be differences. Do DFROBOT send me the wrong product?
Appreciate any thoughts or suggestions. I've exhausted everything I can think of.
The “A0221AU” marking may just be an internal marking/serial number, not necessarily the actual product model.
For the checksum errors, I’d suggest testing the sensor outside of ESPHome/Home Assistant first with a basic UART test. Use the simplest wiring:
• Sensor VCC → ESP32 3.3V or 5V
• Sensor GND → ESP32 GND
• Sensor TX → ESP32 RX
• Sensor RX → leave unconnected first
Then check whether it outputs valid 4-byte frames at 9600 baud. Also make sure the RX pin in the test code matches the actual ESP32 pin connected to the sensor TX.
It would help to share the ESP32 board model, full wiring photo, ESPHome YAML, test code if any, checksum error log, sensor power voltage, and photos of the packaging label/sensor marking.
Yx 