ESP32
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ESP32 I2C device not detected on GPIO21 and GPIO22
Asked by alex_maker
•
Aug 21, 2026
I wired an I2C sensor to GPIO21 (SDA) and GPIO22 (SCL) on my ESP32 DevKit v1, but the I2C scanner sketch reports 'No I2C devices found'. Supply voltage is 3.3V.
Expected Result:
I2C Scanner should return device address 0x76.
Actual Result:
Output says: No I2C devices found.
Code Snippet
Wire.begin(21, 22);
Wire.beginTransmission(0x76);
byte error = Wire.endTransmission();