User Manual

4 Hardware

The MTw Development Kit is comprised of both software and hardware. This section deals

with all hardware aspects. The hardware of the MTw development kit includes the motion

trackers, the Awinda Station and the click-in body straps.

4.1 Motion Trackers (MTw)

The MTw provides 3D angular velocity using rate gyroscopes, 3D acceleration using

accelerometers, 3D earth magnetic field using magnetometers, as well as atmospheric

pressure using the barometer. Combined with Xsens algorithms, 3D drift-free orientation is

provided. The MTw is an excellent measurement unit for orientation measurement of

human body segments, in particular because it is also designed to maintain very high

accuracy time synchronization of the individual sensor readout across a wireless network of

multiple units. This is essential when measuring joint angles accurately.

Front side of the MTw where the micro

USB is connected. On the top is LED giving

indications of device status.

Back side of the MTw, displaying various

regulatory notices and 2D barcodes used

by Xsens for quality control and tracking, as

well as the MTw product code (MTw-

38A70G20) and serial number

(SN). Note

that the last three digits of the SN are

displayed in a large font, for the user to

easily identify individual MTw’s. This aids

the user for example when placing MTw’s

on particular body segments.

The MTw is powered using a LiPo battery. The battery can be in operation for up to 3.5

hours, in stand-by for approximately 90 hours and is fully recharged after one hour docked in

the Awinda Station (with a power supply connected to the Awinda Station). For more

technical details on the MTw, sensor component specifications and orientation

performance, see Section 11.1.

Also known as Device ID.