Tag Archives: gyroscope

Python Code for BerryIMU – Accelerometer, Gyroscope, Magnetometer & Pressure Sensor

We have updated our git repository with python code for the BerryIMU.

This is specific for the BerryIMU, however the math and code can be applied to any digital IMU, just some minor modifications need to be made. E.g  Pololu MinIMU, Adafruit IMU and Sparkfun IMUs

Git repository here
The code can be pulled down to your Raspberry Pi with;

pi@raspberrypi ~ $ git clone http://github.com/mwilliams03/BerryIMU.git

 

We have left the code as simple as it can be to make it easier to understand.

The code currently performs angle measurements using the gyroscope and accelerometer , which are fused using a complementary filter. The heading is also calculated using the magnetometer, without tilt compensation.
BerryIMU Raspberry Pi Gyroscope Accelerometer
To view pressure;

pi@raspberrypi ~ $ sudo python berryIMU.py

To view pressure;

pi@raspberrypi ~ $ sudo python bmp180.py

Detailed Guides and Tutorials

In this order;
Guide to interfacing a Gyro and Accelerometer with a Raspberry Pi – Kalman Filter
Create a Digital Compass with the Raspberry Pi – Part 1 – “The Basics”
Create a Digital Compass with the Raspberry Pi – Part 2 – “Tilt Compensation”
Create a Digital Compass with the Raspberry Pi – Part 3 – “Calibration”
Create a Digital Compass with the Raspberry Pi – Part 4- “Smartphone Replica”
Converting values from an Accelerometer to Gs – “ Proper Acceleration”

How to Create an Inclinometer using a Raspberry Pi and an IMU
Raspberry Pi Digital Spirit Level

Guide to interfacing a Gyro and Accelerometer with a Raspberry Pi

This guide covers how to use an Inertial Measurement Unit (IMU) with a Raspberry Pi . This is an updated guide and improves on the old one found here.

In this guide I will explain how to get readings from the IMU and convert these raw readings into usable angles. I will also show how to read some of the information in the datasheets for these devices.

This guide focuses on the BerryIMU. However, the theory and principals below can be applied to any digital IMU, just some minor modifications need to be made. Eg  Pololu MinIMU, Adafruit IMU and Sparkfun IMUs

Git repository here
The code can be pulled down to your Raspberry Pi with;

pi@raspberrypi ~ $ git clone http://github.com/mwilliams03/BerryIMU.git

 

The code for this guide can be found under the gyro_accelerometer_tutorial01_angles directory.

A note about Gyros and Accelerometers

When using the IMU to calculate angles, readings from both the gyro and accelerometer are needed which are then combined. This is because using either on their own will result in inaccurate readings. And a special note about yaw.

Here is why;
Gyros – A gyro measures the rate of rotation, which has to be tracked over time to calculate the current angle. This tracking causes the gyro to drift. However, gyros are good at measuring quick sharp movements.

Accelerometers – Accelerometers are used to sense both static (e.g. gravity) and dynamic (e.g. sudden starts/stops) acceleration. They don’t need to be tracked like a gyro and can measure the current angle at any given time. Accelerometers however are very noisy and are only useful for tracking angles over a long period of time.

Accelerometers cannot measure yaw.   To explain it simply, yaw is when the accelerometer is on a flat level surface and it is rotated clockwise or anticlockwise.  As the Z-Axis readings will not change, we cannot measure yaw.   A gyro and a magnetometer can help you measure yaw. This will be covered in a future guide.

Here is an excellent tutorial about accelerometers and gyros.

Setting up the IMU and I2C

The IMU used for this guid  a BerryIMU which uses a LSM9DS0, which consists of a 3-axis gyroscope, a 3-axis accelerometer and a 3-axis magnetometer.
The datasheet is needed if you want to use this device;LSM9DS0

This IMU communicates via the I2C interface.

The image below shows how to connect the BerryIMU to a Raspberry Pi

Raspberry Pi BerryIMU

IMU Raspberry Pi Accelerometer gyro

Or BerryIMU can sit right on top of the GPIO pins on a Raspberry Pi A, B, B+ and A+.   The first 6 GPIOs are used as shown below.

IMU Raspberry Pi Accelerometer gyro

Continue reading Guide to interfacing a Gyro and Accelerometer with a Raspberry Pi

New Kickstarter Launched – BerryIMU

An accelerometer, gyroscope and magnetometer which is specifically designed for the Raspberry Pi.

 

What is it?

BerryIMU is an inertial measurement unit, or IMU, that measures and reports on velocity, orientation and gravitational forces, using a combination of an accelerometer, gyroscope and a magnetometer.

IMUs can be found in devices like, quad copters, smart phones, segways, Wii Remote etc.. and are used to sense movement and orientation.

BerryIMU for the raspberry pi

Adding BerryIMU to your Pi will open up a whole new world of possibilities.

BerryIMU is specifically designed for the Raspberry Pi and is designed to take some of the complexity out of IMUs and to try and make them more enjoyable to use. BerryIMU includes the latest and greatest sensor ICs.

Head on over to Kickstarter.com to check it out;
https://www.kickstarter.com/projects/2135028730/berryimu-orientation-sensor-for-the-raspberry-pi