The Arduino Uno Rev3 is the third revision of the classic Arduino Uno board. Compared to its earlier iterations, ... a more robust circuit for resetting the board, and additional SDA and SCL pins.

When working with Arduino boards for the first time, you're bound to make some mistakes, ... (SDA to A4 and SCL to A5). That said, you can't use them at the same time.

Shown below is the basic hardware setup diagram. Here, Arduino’s (Uno R3) A4 (SDA) and A5 (SCK/SCL) pins are used for the I2C control, and the module is 3.3 V powered by the Arduino itself. It seems ...