5 | How to calibrate the MPU6050 with Arduino and Teensy

Summary

In this video, viewers learn how to calibrate the gyroscope of their TNC-controlled quadcopter. The session explores how to adjust the rotation rate measurements, ensuring accurate values for roll, pitch, and yaw. Calibration is explained as a process of averaging sensor readings when the sensor is stationary to account for inherent fluctuations. After taking 2,000 measurements, viewers integrate the calibration calculations into their code and test the gyro's accuracy. The video concludes by encouraging viewers to test their results and prepare for upcoming motor and receiver tests in the next video.

Takeaways

• 😀 Calibration is crucial for gyroscope measurements to represent real physical values.
• 😀 To calibrate the gyroscope, average a large number of uncorrected measurements when the sensor is stationary.
• 😀 The roll, pitch, and yaw rotation rates should be zero when the sensor is not moving.
• 😀 Gyroscope measurements tend to fluctuate due to small environmental vibrations, so calibration helps to offset these variations.
• 😀 The code from the previous video needs to be updated with four additional variables to store calibration values.
• 😀 A for loop is created in the program to gather 2,000 measurement values from the gyroscope for calibration.
• 😀 Each measurement is taken 1 millisecond apart, resulting in a 2-second calibration period.
• 😀 The sum of the 2,000 measurement values is averaged, and the resulting value is subtracted from future measurements.
• 😀 The quadcopter or breadboard should remain stationary during calibration to ensure accurate zero-rate measurements.
• 😀 After calibration, the corrected rotation rate values should be printed to the serial monitor and should be close to zero when the sensor is stationary.

Q & A

What was explored in the previous video of the series?

In the previous video, the focus was on the orientation sensor or gyroscope, specifically how to measure the roll, pitch, and yaw rotation rates using the MPU 6050 gyroscope.

What strange behavior was observed when testing the rotation rates?

The strange behavior was that the roll rotation rates were not always equal to zero, even though the breadboard did not move. The pitch and yaw rotation rates also showed non-zero values, though much smaller.

Why were non-zero rotation rates observed even when the sensor wasn't moving?

This occurred because the sensor needed to be calibrated to set a reference point. The sensor's measurements were fluctuating due to small vibrations in the environment.

What does calibration of the gyroscope sensor involve?

Calibration involves adjusting the measurements of the sensor so that they correspond with real physical values, specifically by setting the rotation rate to zero when the sensor is not moving.

What value should the rotation rate have when the sensor is stationary?

When the sensor is stationary, the rotation rate should ideally be zero.

How is calibration performed in the script?

Calibration is performed by measuring the sensor's output when it is stationary, averaging the values over a large number of measurements (2000), and then subtracting this average from all future measurements to correct the values.

What variables are added to the original code for calibration?

Four additional variables are added to store the calibration values for roll, pitch, and yaw rotation rates, as well as a variable to keep track of the number of measurements taken.

Why is it important not to move the breadboard during the calibration phase?

It is crucial not to move the breadboard during the calibration phase to ensure that the sensor receives stable data that represents a rotation rate of zero.

What is the purpose of the for loop in the setup part of the program?

The purpose of the for loop is to collect 2,000 measurements from the gyroscope, spaced one millisecond apart, in order to calculate the calibration values by averaging these readings.

What should be done after the calibration values have been determined?

Once the calibration values are determined, they should be subtracted from future sensor readings to obtain the corrected rotation rates, which can then be printed to the serial monitor.

What should be done during testing after uploading the code?

During testing, you should hold the breadboard stationary for the first two seconds after uploading the code to ensure accurate calibration and measure the rotation rates after rolling, pitching, and yawing the breadboard in different directions.

What is the expected outcome after testing the rotation rates?

After testing, the rotation rates should have values very close to zero when the breadboard is stationary again, indicating successful calibration of the gyroscope.