smartIMU

This project is shared with the Embedded Computing website, as the whole development is carried out with the tools I use for embedded computing, including embedXcode.

The 519143 Robotics Competition Set features a new I²C sensor, the gyro-sensor (reference 158402) based on a BMX055.
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​Functional Description

The BMX055 (data-sheet) by Bosch SensorTec combines 9-DOF IMU (9 degrees of freedom inertial measurement unit) with a 3-axis acceleration sensor, a 3-axis gyroscope and a 3-axis geomagnetic sensor.

However, it only  provides raw data, and does not include any MCU to fusion data and compute angles.

Another sensors on the extensive range of Bosch SensorTec are the BNO055 (data-sheet) and BNO080 (data-sheet), which offer the same 9-DOF IMU but include a built-in Cortex-M0+ MCU for data fusion and angle computation, including Euler angles, quaternion, rotation vector, linear acceleration. The smartIMU sensor is based on this range of sensors.

​Commands

The smartIMU relies on a limited set of commands:
  • IMU_begin  checks the I²C connection with the sensor and initialises the sensor.
  • IMU_setConfiguration configures the units and orientation of the IMU.
  • IMU_getEuler gets the Euler angles (roll, pitch and yaw).
  • IMU_getLinearAcceleration gets the linear acceleration.
  • IMU_getGravityVector gets the gravity vector.
  • IMU_getQuaternion gets the quaternion.
  • IMU_getAccelerometer gets the acceleration data.
  • IMU_getGyroscope gets the gyroscope data.
  • IMU_getMagnetometer gets the magnetometer data.

​First Prototype

The prototype was built on a breadboard and tested with a MCU-based board, then with the RoboTX controller.

​The sensor worked fine on the first test.

​Finalised and Working Sensor

The sensor is finalised, integrated into a standard fischertechnik 9 V battery box and working!