# 9-Axis IMU LESSON 7: Understanding Low Pass Filters

In this project, we have shown how accelerometers can be used to approximate tilt. We showed in Lesson 6 how vibration can cause a problem with such a strategy, as the system will interpret vibration to be changes in tilt. A partial solution to this problem can be to program a low pass filter into the project. The video above introduces you to the concept of a low pass filter, and shows some simple examples of programming and using a low pass filter to reduce noise.

The code below is for demo purposes only, and should not be used in any real applications. It just demonstrates how to work with this sensor in benchtop presentations.

# 9-Axis IMU LESSON 6: Determine Tilt From 3-axis Accelerometer

This lesson shows you some of the simple math, that will allow you to approximate tilt angle from a three axis accelerometer. In this entire series of lessons, we are using the BNO055 9-axis sensor connected to an Arduino Nano. It is possible to approximate tilt along the x-axis and tilt along the y-axis. These could roughly be considered to be like the Euler Angles of Pitch and Roll. It should be noted that the approximations are reasonable for tilt angles less than 45 degrees. Also note, that in this simple demonstration, real acceleration will be interpreted as tilt, hence the system will incorrectly interpret motion as tilt. Because of this, this approach should not be used on things like drones or other moving systems. It is just for simple demonstration purposes.

The code developed in the video above is included below for your convenience.

The code below is for demo purposes only, and should not be used in any real applications. It just demonstrates how to work with this sensor in benchtop presentations.

# 9-Axis IMU LESSON 5: Calibrating the BNO055 9-axis Inertial Measurement Sensor

In this lesson we show you how to get a clean calibration on your BNO055 9-axis sensorIn the video below we take you through the coded needed to calibrate the sensor, and a simple technique to quickly get the system properly calibrated.

The code developed in this video will be used in future lessons, and is included below:

The code below is for demo purposes only, and should not be used in any real applications. It just demonstrates how to work with this sensor in benchtop presentations.