MPU6050 Introduction – SparkFun
Accelerometer, Gyro and IMU Buying Guide – SparkFun
Accelerometers and gyros are becoming increasingly popular in consumer electronics, so maybe it’s time you added them to your project! Scrolling through SparkFun’s sensors category reveals a huge list of these sensors that might be perfect for your next project, if only you knew what they did, and which one best fit your project.
The goal of this buying guide is to get you speaking the same language as these sensors’ datasheets and to help you select the one that is best-suited for your needs.
What’s an accelerometer measure? Well, acceleration. You know…how fast something is speeding up or slowing down. You’ll see acceleration displayed either in units of meters per second squared (m/s2), or G-force (g), …
Accelerometers are used to sense both static (e.g. gravity) and dynamic (e.g. sudden starts/stops) acceleration. One of the more widely used applications for accelerometers is tilt-sensing. Because they are affected by the acceleration of gravity, an accelerometer can tell you how it’s oriented with respect to the Earth’s surface. For example, Apple’s iPhone has an accelerometer, which lets it know whether it’s being held in portrait or landscape mode. An accelerometer can also be used to sense motion. For instance, an accelerometer in Nintendo’s WiiMote can be used to sense emulated forehands and backhands of a tennis racket, or rolls of a bowling ball.
Finally, an accelerometer can also be used to sense if a device is in a state of free fall. This feature is implemented in several hard drives: if a drop is sensed, the hard drive is quickly switched off to protect against data loss.
Now that you know what they do, let’s consider what characteristics you should be looking for when selecting your accelerometer:
Range , …
Interface, … digital accelerometers usually feature a serial interface be it SPI or I²C.
Number of axes measured – This one’s very straightforward: out of the three axes possible (x, y, and z), how many can the accelerometer sense? Three-axis accelerometers are usually the way to go; Power Usage, … Bonus Features, …
Gyroscopes measure angular velocity, how fast something is spinning about an axis. If you’re trying to monitor the orientation of an object in motion, an accelerometer may not give you enough information to know exactly how it’s oriented. Unlike accelerometers gyros are not affected by gravity, so they make a great complement to each other.
In the past, gyros have been used for space navigation, missile control, under-water guidance, and flight guidance. Now they are starting to be used alongside accelerometers for applications like motion-capture and vehicle navigation.
A lot of what was considered when selecting an accelerometer still applies to selecting the perfect gyro: Range, … Number of axes measured, … Power Usage, …
Gyroscopes and accelerometers are great, but alone they don’t give you quite enough information to be able to comfortably calculate things like orientation, position, and velocity. To measure those and other variables many people combine the two sensors, to create an inertial measurement unit (IMU) which provides two to six degrees of freedom (DOF). IMUs are widely used in devices that require knowledge of their exact position, for example robotic arms, guided missiles, …
SparkFun’s IMUs can really be broken down into two classes: simple IMU combo boards, which just mount an accelerometer and gyro onto a single PCB, and more complex units that interface a microcontroller with the sensors to produce a serial output, …