Multiwii Arduino Uno R3 Quadcopter Accel not working

Hello all,

I've assembled a quadcopter using Arduino Uno R3 , Gy-521 with Multiwii. I've used this schematic


Everything worked great with the solderless cables from Arduino, so I started soldering.

Everything soldered and the Gy-521 doesn't seem to work properly when I use the MultiwiiConf GUI. It doesn't move or anything. It goes crazy whenever I remove the VCC or SCL and then stops, which means it is not dead. The LED flashes brightly and it's connected to the Ground and 3.3v in the board.

  • I've bought 3 new ones, same result with all of them, its not the MPU board.
  • Switched cables
  • Switched between A4 and A5 and SCL and SDA on the Arduino
  • Removed everything else and tested only with the Accel on
  • The battery on / only USB
  • 3.3v Pin and 5v Pin
  • Changed between Gy-521 and NanoWii sensor
  • I2C speed 10000 / 40000
  • define internal I2c
  • Calibrated Accel in the GUI
  • Everything I can think of at this point really...
  • Everything was working well, I even used the same code after the solder at first, even disconnected everything and testing only with the sensor didn't have any changes.

Any other idea?

I could've simply used a FC, but I really wanted to complete this project with the Arduino UNO.