The best combination of sensors to make a flight controller.

To stabilize and guide the quadcopter autonomously - independent of the algorithms they are used - it needs the combination of multiple sensors. Initially, it will use an accelerometer, a gyroscope and a compass. To guide him inside of the buildings will use ultrasonic sensors. A simple GPS, will guide the helicopero between two points in outdoor environment.

After doing some research, I came to the conclusion that the best combination would be to use the board "IMU 6DOF Razor - Ultra-Thin IMU" with the board "Triple Axis Magnetometer Breakout - HMC5843". The first board makes use of ST's LPR530AL (pitch and roll) and LY530ALH (yaw) gyros, as well as the ADXL335 triple-axis accelerometer, to give six degrees of measurement. The second board is a breakout board for Honeywell's HMC5843, a 3-axis digital compass. Communication with the HMC5843 is simple and all done through an I2C interface. The two boards together provide nine degrees of measurement.

But when I had already decided by the combination indicated above, I discovered the same combination, but which joins the three sensors (aceleromentro, gyroscope and compass) in a single board. The board “9 Degrees of Freedom - Razor IMU - AHRS compatible” incorporates the same four sensors of the boards described above - an LY530AL (single-axis gyro), LPR530AL (dual-axis gyro), ADXL345 (triple-axis accelerometer), and HMC5843 (triple-axis magnetometer) - to give nine degrees of inertial measurement. The outputs of all sensors is processed by on-board ATmega328 and sent out via a serial stream. I think this is will be the best solution for an autonomous quadcopter.