Paid Review - The supplier offered to refund the purchase price of this item in exchange for a review. It's an item I was buying anyway. This article was written before receiving the refund.
The MPU9250 is available as a module on Amazon in the UK here with
Prime shipping, or cheaper from China at all the usual places.
It's a "9 axis" device - a gyroscope, accelerometer and magnetometer all in one. Each of the three devices provides a 3D reading, so the accellerometer can be used to detect which way up the module is, and changes in speed in any direction. The gyroscope measures the twist rate, as the device is rotated about any axis, and the magnetometer provides magnetic field readings on 3 planes to act as a compass or to report on any other magnetic fields.
The application I had in mind for this module uses a number of I2C sensors already, so the MPU9250 fits in nicely with the hardware and software I was already working with. I don't need the gyroscope, but do need to be able to associate the magnetic and orientation readings.
To evaluate this device, I wrote a simple PC application in Delphi XE4 to graph the data, after formatting the readings as a CSV stream to send over serial from an arduino. There are download links below for the sketch and the viewer application.
Summary: Does what it says. Twice the price of similar items direct from China, but doesn't take weeks to arrive.
Recommend it: Yes, if you're in a hurry or need easy returns for a small project.
But it again: Probably. I rarely use this item, so would pay the premium to get it next day.