The MPU6050 and special Motor controllers allows I2C communication protocol, there is no need for PWM signal.

• 4x Robbe Roxxy 2827/34 Brushless Motor
• 4x BL-Ctrl V1.2 (equivalent to ESC – electronic speed controller)
• Raspberry Pi
• Arduino+RFM12 for Radio transmission over ttyUSB0
• MPU6050 Gyro and Acc Motion Sensor
• 3-Axis Digital Compass HMC5883L (not in use)
• ublox5 GPS (not in use)
• WiFi Dongle to ssh into the RPi (not in use)
• 2700 mAh 3S LiPo Battery

With all the Parts, the whole quadcopter weights about 1 KG including battery.

Quadcopter Software Programming

The software was written in C++, and Marlon is so kind to share with everyonehere. The Software is mostly written by himself therefore most Parameters, e.g. PID, are not comparable to other quadcopters.

The sensor sampling  frequency is about 300 Hz to 500 Hz and the motors are controlled at 50 Hz. Most of the Software processing time is spent on waiting for sensor data due to the slowness of I2C. The actual computation takes barely no time even though everything is down in floating point numbers.