Tag Archives: featured1

GPS Data logger using a BerryGPS

This post explains how to log GPS data from a BerryGPS or a BerryGPS-IMU and then how to plot this data onto Google Maps and many other maps E.g. OpenStreet, WorldStreet, National Maps, etc..

Raspberry Pi GPS

1. Setup GPS

Follow the instructions on this page to setup your Raspberry Pi for a BerryGPS. Ensure GPSD is set to automatically start and confirm that you can see the NMEA sentences when using gpsipe;

pi@raspberrypi ~ $ gpspipe -r

 

2.  Automatically Capture Data on Boot.

We will be using gpspipe to capture the NMEA sentence from the BerryGPS and storing these into a file. The command to use is;

pi@raspberrypi ~ $ gpspipe -r -d -l -o /home/pi/`date +”%Y%m%d-%H-%M-%S”`.nmea

-r = Output raw NMEA sentences.
-d = Causes gpspipe to run as a daemon.
-l = Causes gpspipe to sleep for ten seconds before attempting to connect to gpsd.
-o = Output to file.

The date the file is created is also added to the name.

Now we need to force the above command to run at boot. This can be done by editing the rc.local file.

pi@raspberrypi ~ $ sudo nano /etc/rc.local

 

Just before the last line, which will be ‘exit 0’, paste in the below line;

gpspipe -r -d -l -o /home/pi/`date +"%Y%m%d-%H-%M-%S"`.nmea

Reboot and confirm that you can see a .nmea file in the home directory.

Continue reading GPS Data logger using a BerryGPS

New Products : BerryGPS and BerryGPS-IMU

We have released two new products:

BerryGPSGPS for the Raspberry Pi

BerryGPS-IMU GPS and IMU for the Raspberry Pi

Both GPS modules use the  M10478-A2 from Antenova, which is a high quality GPS module which is able to track 22 satellites and has an internal antenna. This means no external antenna is needed if the module has clear access to sky.  Both feature a SuperCap to store ephemeris data for up to four hours. This and many more features are included.

Raspberry Pi GPS
BerryGPS

 

 

 

Both have been specifically designed for the Raspberry Pi Zero, however they will work with any version of Raspberry Pi.

 

The BerryGPS-IMU also includes all the components found on the BerryIMU.  And is compatible with the existing code in our repository. The BerryGPS-IMU present a lot of sensors in a very, very small package.

 

 

Raspberry Pi GPS
BerryGPS-IMU

 

 

 

Raspberry Pi GPS
BerryGPS-IMU on a Raspberry Pi Zero

 

BerryGPS-IMU
BerryGPS-IMU on Raspberry Pi 2

berrygps-skull

Raspberry Pi 3 + LED Cube + Spectrum Analyzer = Awesome Audio Visualizer!

To create an awesome audio visualizer, using a spectrum analyzer( C.A.V.A:  Console-based Audio Visualizer for ALSA ), all you need is a Raspberry Pi 3 and a RGB LED cube – VoxCube!

Raspberry Pi LED cube

C.A.V.A

CAVA was created by Karl Stavestrand and it is a  great tool to create an audio visualizer in the console.

C.A.V.A spectrum analyzer Raspberry Pi

Continue reading Raspberry Pi 3 + LED Cube + Spectrum Analyzer = Awesome Audio Visualizer!

BerryIMU code for Arduino – Accelerometer, Gyroscope and Magnetometer

Our GIT repository has been updated with an Arduino sketch which calculates angles using a complementary filter.  The heading is also calculated using the magnetometer.

 BerryIMU Arduino

 

BerryIMU Arduino Wiring

 

 

 

BerryIMU Raspberry Pi Gyroscope Accelerometer

Detailed Guides and Tutorials

In this order;
Guide to interfacing a Gyro and Accelerometer with a Raspberry Pi
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”

 

These cover both BerryIMU and displaying graphics with SDL on a Raspberry Pi;
How to Create an Inclinometer using a Raspberry Pi and an IMU

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

 

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

Wiring BerryIMU to Raspberry Pi

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

Create a Digital Compass with the Raspberry Pi – Part 1 – “The Basics”

This will be a multipart series on how to use a digital compass(magnetometer) with your Raspberry Pi.

The magnetometer used in these tutorials is a LSM9DS0 which is on a BerryIMU. We will also point out where some of the information can be found in the Datasheet for the LSM9DS0. This will help you understand how the LSM9DS0 works.

The math and logic in this series can also be used with other magnetometers or IMUs.

We will also go over how to do some basic communication on the i2c bus. As well as using SDL to display the compass heading as traditional compass as shown in the video above.

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

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

Overview of a Compass

Raspberry Pi Compass
A traditional Magnetic compass (as opposed to a gyroscopic compass) consists of a small, lightweight magnet balanced on a nearly frictionless pivot point. The magnet is generally called a needle. The Earth’s Magnetic field will cause the needle to point to the North Pole.

To be more accurate, the needle points to the Magnetic North. The angle difference between true North and the Magnetic North is called declination. Declination is different in different locations. This angle varies depending on position on the Earth’s surface, and changes over time.

The strength of the earth’s magnetic field is about 0.5 to 0.6 gauss .

Continue reading Create a Digital Compass with the Raspberry Pi – Part 1 – “The Basics”