Gyroscope vs Accelerometer?

iphone ios4 accelerometer gyroscope
Moshe picture Moshe · Jun 22, 2010 · Viewed 43.1k times · Source

Now that iOS 4 is no longer NDA, I would like to know what Gyroscope has to offer over the Accelerometer for developers. Is there a difference in APIs? Other things?

Answer

Yann Ramin picture Yann Ramin · Jun 22, 2010

A MEMs gyroscope is a rate of change device. As the device rotates in any its axis, you can see a change in rotation. An accelerometer only provides the force along the X,Y,and Z vectors, and cannot solve for "twist". By using both sensors, you can often implement what is referred to as a 6DOF (degrees of freedom) inertial system - or dead reckoning - allowing you to find the relative physical location of the device. (Note that all inertial systems drift, so its not stable in the long term).

In short: gyroscopes measure rotation, accelerometers measure translation.

There is a new API for reading the gyroscope.

Related questions

Getting displacement from accelerometer data with Core Motion

I am developing an augmented reality application that (at the moment) wants to display a simple cube on top of a surface, and be able to move in space (both rotating and displacing) to look at the cube in all …

Read More
iOS: Movement Precision in 3D Space

From what I understand, GPS has limited accuracy. Is it possible to get a more precise location for a person in 3D space? I'm planning to write an application where users will move with their phones in any direction, but …

Read More
track small movements of iphone with no GPS

I have to write an application for iphone that tracks the movement of the iphone itself, given its initial position, without ever using GPS. That is, I can only use data provided by the gyroscope and the accelerometer. The distances …

Read More