as the title says, I have:
- Arduino Uno R3
- LCM1602 IIC V1, soldered like this: VCC -> 5V, GND -> GND, SDA -> A4, SCL -> A5
- Also a BH1750 light sensor soldered the same way
LCD was not working (squares not replaced with text), so I tried this scanner: http://playground.arduino.cc/Main/I2cScanner
Here are results:
- If both are connected, it hangs on the first Wire.endTransmission();
- If only LCD is connected, same thing happens
- If only BH1750 is connected, it detects its 0x23 address correctly
Also, if you leave three cables soldered to LCD - VCC, GND and SDA - the scanner doesn't hang. It hangs if you leave only VCC, GND and SCL. There's 0 voltage on empty SDA and ~1 on SCL.
What could this mean? I see no short circuit (if there was one, which one is the most likely one?), could the LCD be just broken? Or do I need resistance somewhere?