Adafruit 10-DOF IMU Breakout

by Kevin Townsend

published November 29, 2013, last updated March 08, 2024

posted in Sensors Adafruit Products Breakout Boards/ Accel, Gyro, & Magnetometers

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Intermediate

Product guide

Introduction

Please note that there is a small cosmetic error on the first revision of these boards (shown above). The straight X arrow for the accelerometer should be pointing in the opposite direction, towards the right. This will be fixed in the next run of these boards.

Adafruit's 10DOF (10 Degrees of Freedom) breakout board allows you to capture ten (err, eleven!) distinct types of motion or orientation related data.

After testing a lot of combinations of sensors, we settled on the following devices that we think offer the best results and the least amount of hassle:

LSM303DLHC - a 3-axis accelerometer (up to +/-16g) and a 3-axis magnetometer (up to +/-8.1 gauss) on a single die
L3GD20 - a 3-axis gyroscope (up to +/-2000 dps)
BMP180 - A barometric pressure sensor (300..1100 hPa) that can be used to calculate altitude, with an additional on-board temperature sensor

Basic Setup (5V Logic, Arduino Uno, etc.)

We'll be using an Arduino UNO here, but the code will work on a Mega or Leonardo just fine. Most other Arduino compatibles should have no problems either but we only support official Arduinos for code.

Connect the SCL pin on the breakout to the SCL pin on your Arduino. On an UNO & '328 based Arduino, this is also known as A5, on a Mega it is also known as digital 21 and on a Leonardo/Micro, digital 3
Connect the SDA pin on the breakout to the SDA pin on your Arduino. On an UNO & '328 based Arduino, this is also known as A4, on a Mega it is also known as digital 20 and on a Leonardo/Micro, digital 2
Connect the VIN pin on the breakout to 3.3V or 5V on your Uno (5V is preferred but if you have a 3V logic Arduino 3V is best)
Connect the GND pin on the breakout to the GND pin on your Uno

That's it! With those four wires, you should be able to talk to any of the I2C chips on the board and run any of the example sketches.

Advanced Setup

While most people probably won't need to use the pins below, we've also broken out a few extra pins for advanced users or for special use cases. If you need to use any of these pins, simply hook them up to a GPIO pin of your choice on the Uno:

GINT - The interrupt pin on the L3GD20 gyroscope
GRDY - The 'ready' pin on the L3GD20 gyroscope
LIN1 - Interrupt pin 1 on the LSM303DLHC
LIN2 - Interrupt pin 2 on the LSM303DLHC
LRDY- The ready pin on the LSM303DLHC

These pins are all outputs from the 10-DOF breakout and are all 3.3V logic, you can use them with 5V or 3V as 3.3V registers 'high' on 5V systems.

3V3 Setup

If you are using an MCU or board with 3V3 logic (instead of the 5V logic used by the Arduino Uno), you can still power the 10-DOF with the VIN pin or you can use the 3Vo pin, which will bypass the on-board 3V3 regulator and level shifting:

Connect Vin or 3Vo on the breakout to the 3.3V supply on your target MCU
Connect GND on the breakout to GND on the target MCU

Like other breakouts on Adafruit, the 10 DOF Breakout is fully level shifted, and you can safely use it on 3V3 or 5V systems.

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Installing LSM303DLHC, L3GD20, and BMP180 Drivers

You will need to install all of the following libraries to make use of the Adafruit 10DOF breakout:

For information on the Adafruit Sensor Library and the Unified Sensor Drivers used for all of these sensors, feel free to have a look at our related learning guide: Using the Adafruit Unified Sensor Driver

Downloading Libraries

To use these libraries, you should download them from the Arduino Library Manager.

Open up the Arduino Library Manager:

Search for the Adafruit Unified Sensor library and install it

Search for the Adafruit L3GD20 library and install it

Search for the Adafruit BMP085 Unified library and install it

Search for the Adafruit 10DOF library and install it

If you're new to installing libraries, check out our super-awesome detailed tutorial on how to install Arduino libraries

Adafruit_10DOF Library Helper Functions

The Adafruit_10DOF.cpp file (from Adafruit_10DOF) includes the following helper functions that are useful when working with typicaly 10DOF projects

bool accelGetOrientation ( sensors_event_t event, sensors_vec_t orientation )

This function reads the LSM303DLHC accelerometer data (supplied via the 'event' variable), and converts it into equivalent pitch (x) and roll (y) values, populating the supplied 'orientation' variables .pitch and .roll fields accordingly.

Arguments

event: The sensors_event_t variable containing the data from the accelerometer

orientation: The sensors_vec_t object that will have its .pitch and .roll fields populated

Returns

true if the operation was successful,
false if there was an error

Example

See the 'pitchrollheading' example in the Adafruit_10DOF library for an example of how to use this helper function

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sensors_event_t accel_event;
sensors_vec_t   orientation;

/* Calculate pitch and roll from the raw accelerometer data */
accel.getEvent(&accel_event);
if (dof.accelGetOrientation(&accel_event, &orientation))
{
  /* 'orientation' should have valid .roll and .pitch fields */
  Serial.print(F("Roll: "));
  Serial.print(orientation.roll);
  Serial.print(F("; "));
  Serial.print(F("Pitch: "));
  Serial.print(orientation.pitch);
  Serial.print(F("; "));
}

sensors_event_t accel_event;
sensors_vec_t   orientation;

/* Calculate pitch and roll from the raw accelerometer data */
accel.getEvent(&accel_event);
if (dof.accelGetOrientation(&accel_event, &orientation))
{
  /* 'orientation' should have valid .roll and .pitch fields */
  Serial.print(F("Roll: "));
  Serial.print(orientation.roll);
  Serial.print(F("; "));
  Serial.print(F("Pitch: "));
  Serial.print(orientation.pitch);
  Serial.print(F("; "));
}

bool magGetOrientation ( sensors_axis_t axis, sensors_event_t event, sensors_vec_t mag_orientation )

This function populates the .heading field in mag_orientation with the correct angular data (0-359°). Heading increases when rotating clockwise around the specified axis.

Arguments

axis: The given axis (SENSOR_AXIS_X, SENSOR_AXIS_Y, or SENSOR_AXIS_Z)
event: The raw magnetometer sensor data to use when calculating out heading
orientation: The sensors_vec_t object where we will assign an 'orientation.heading' value

Returns

true if the operation was successful,
false if there was an error

Example

See the 'pitchrollheading' example in the Adafruit_10DOF library for an example of how to use this helper function

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sensors_event_t mag_event;
sensors_vec_t   orientation;
  
/* Calculate the heading using the magnetometer */
mag.getEvent(&mag_event);
if (dof.magGetOrientation(SENSOR_AXIS_Z, &mag_event, &orientation))
{
  /* 'orientation' should have valid .heading data now */
  Serial.print(F("Heading: "));
  Serial.print(orientation.heading);
  Serial.print(F("; "));
}

sensors_event_t mag_event;
sensors_vec_t   orientation;
  
/* Calculate the heading using the magnetometer */
mag.getEvent(&mag_event);
if (dof.magGetOrientation(SENSOR_AXIS_Z, &mag_event, &orientation))
{
  /* 'orientation' should have valid .heading data now */
  Serial.print(F("Heading: "));
  Serial.print(orientation.heading);
  Serial.print(F("; "));
}

bool magTiltCompensation ( sensors_axis_t axis, sensors_event_t mag_event, sensors_event_t accel_event )

This function uses the accelerometer data provided in accel_event to compensate the magnetic sensor measurements in mag_event to compensate for situations where the sensor is tilted (the pitch and roll angles are not equal to 0°).

Arguments

axis: The given axis (SENSOR_AXIS_X, SENSOR_AXIS_Y, or SENSOR_AXIS_Z) that is parallel to the gravity of the Earth
mag_event: The raw magnetometer data to adjust for tilt
accel_event: The accelerometer event data to use to determine the tilt when compensating the mag_event values

Returns

true if the operation was successful,
false if there was an error

Example

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sensors_event_t accel_event;
sensors_event_t mag_event;

...

// Get a sensor event from the accelerometer and magnetometer
accel.getEvent(&accel_event);
mag.getEvent(&mag_event);

if (dof.magTiltCompensation(SENSOR_AXIS_Z, &mag_event, &accel_event))
{
  // Do something with the compensated data in mag_event!
}
else
{
  // Oops ... something went wrong (probably bad data)
}

sensors_event_t accel_event;
sensors_event_t mag_event;

...

// Get a sensor event from the accelerometer and magnetometer
accel.getEvent(&accel_event);
mag.getEvent(&mag_event);

if (dof.magTiltCompensation(SENSOR_AXIS_Z, &mag_event, &accel_event))
{
  // Do something with the compensated data in mag_event!
}
else
{
  // Oops ... something went wrong (probably bad data)
}

Example Sketch

If you run the pitchrollheading sketch in the examples folder, you can see a practical example using these helper functions above, which should result in output similar to the image below: