MPU-6050 Accelerometer + Gyro
The MPU-6050 devices combine a 3-axis gyroscope and a 3-axis accelerometer on the same silicon die, together with an onboard Digital Motion Processor™ (DMP™), which processes complex 6-axis MotionFusion algorithms. The device can access external magnetometers or other sensors through an auxiliary master I²C bus, allowing the devices to gather a full set of sensor data without intervention from the system processor.
http://playground.arduino.cc/Main/MPU-6050 or find this page here
https://diyhacking.com/arduino-mpu-6050-imu-sensor-tutorial/ or find this page here
MPU6050 Arduino library