BNO080 Driver¶

by Jamie Smith / USC Rocket Propulsion Lab

After weeks of development, we are proud to present our driver for the Hilcrest BNO080 IMU! This driver is inspired by SparkFun and Nathan Seidle's Arduino driver for this chip, but has been substantially rewritten and adapted.

It supports the main features of the chip, such as reading rotation and acceleration data, as well as some of its more esoteric functionality, such as counting steps and detecting whether the device is being hand-held.

Features¶

• Support for 15 different data reports from the IMU, from acceleration to rotation to tap detection
• Support for reading of sensor data, and automatic checking of update rate against allowed values in metadata
• BNO_DEBUG switch enabling verbose, detailed output about communications with the chip for ease of debugging
• Ability to tare sensor rotation and set mounting orientation
• Fully synchronous and does not use interrupts, so operation is reliable and repeatable
• Calibration function
• Reasonable code size for what you get: the library uses about 4K of flash and one instance of the object uses about 600 bytes of RAM.

Documentation¶

Full Doxygen documentation is available online here

Example Code¶

Here's a simple example:

#include <mbed.h>
#include <BNO080.h>

int main()
{
	Serial pc(USBTX, USBRX);

	// Create IMU, passing in output stream, pins, I2C address, and I2C frequency
	// These pin assignments are specific to my dev setup -- you'll need to change them
	BNO080 imu(&pc, p28, p27, p16, p30, 0x4a, 100000); 

	pc.baud(115200);
	pc.printf("============================================================\n");

	// Tell the IMU to report rotation every 100ms and acceleration every 200ms
	imu.enableReport(BNO080::ROTATION, 100);
	imu.enableReport(BNO080::TOTAL_ACCELERATION, 200);

	while (true)
	{
		wait(.001f);
		
		// poll the IMU for new data -- this returns true if any packets were received
		if(imu.updateData())
		{
			// now check for the specific type of data that was received (can be multiple at once)
			if (imu.hasNewData(BNO080::ROTATION))
			{
				// convert quaternion to Euler degrees and print
				pc.printf("IMU Rotation Euler: ");
				TVector3 eulerRadians = imu.rotationVector.euler();
				TVector3 eulerDegrees = eulerRadians * (180.0 / M_PI);
				eulerDegrees.print(pc, true);
				pc.printf("\n");
			}
			if (imu.hasNewData(BNO080::TOTAL_ACCELERATION))
			{
				// print the acceleration vector using its builtin print() method
				pc.printf("IMU Total Acceleration: ");
				imu.totalAcceleration.print(pc, true);
				pc.printf("\n");
			}
		}
	}

}

If you want more, a comprehensive, ready-to-run set of examples is available on my BNO080-Examples repository.

Credits¶

This driver makes use of a lightweight, public-domain library for vectors and quaternions available here.