Xsens DOT User manual

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Xsens DOT
User Manual
Document XD0502P, Revision D, 15 Dec 2020

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Revision
Date
By
Changes
A
7 Jan 2020
XUF
Initial release
B
25 April 2020
XUF
Add charger spec and attachment method
Add magnetic distortion description
Add cleaning and storage method
Update firmware update operations
Add sensor components specifications
Add coordinate systems
Add heading reset function
Update data outputs information
C
27 August 2020
XUF
Add sync and recording LED
Update software package
Add multiple sensor connection tips
Update state transition diagram
Add synchronization feature
Add recording function
Add firmware compatibility
Update Xsens DOT specifications
D
15 Dec 2020
XUF
Add tutorial video link of unboxing and App
Add long-term storage guidelines
Add button callback function
Update state transition diagram
Update synchronization function
Add a filter profile
Add output rates
Update MFM function for new features
Add firmware update notification
Update firmware compatibility
Add dv and acceleration conversion formula
Add technical drawings of sensor and charger
Add accelerometer reference
© 2005-2020, Xsens Technologies B.V. All rights reserved. Information in this document is subject to change
without notice. Xsens, MVN, MotionGrid, MTi, MTi-G, MTx, MTw, Awinda, Xsens DOT and KiC are registered
trademarks or trademarks of Xsens Technologies B.V. and/or its parent, subsidiaries and/or affiliates in The
Netherlands, the USA and/or other countries. All other trademarks are the property of their respective owners.

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Table of Contents
1Introduction..............................................................................6
2Getting Started.......................................................................... 7
2.1 Xsens DOT set ........................................................................................... 7
2.2 Hardware .................................................................................................. 7
2.2.1 Xsens DOT ........................................................................................... 7
2.2.2 Power button........................................................................................ 8
2.2.3 LED status ........................................................................................... 8
2.2.4 Charger ............................................................................................... 9
2.2.5 Body straps and accessories................................................................... 9
2.3 Software ................................................................................................... 9
2.3.1 Supported platforms.............................................................................10
2.3.2 Choose your software...........................................................................10
2.4 Tips for best practice .................................................................................11
2.4.1 Multiple sensors connection...................................................................11
2.4.2 Magnetic distortion...............................................................................11
2.4.3 Cleaning method..................................................................................12
2.4.4 Long-term storage guidelines ................................................................12
3Xsens DOT Overview ............................................................... 14
3.1 Strapdown integration................................................................................14
3.2 Sensor fusion algorithm and filter profiles.....................................................14
3.3 Xsens DOT sensor state transition ...............................................................15
3.3.1 Power ON/OFF.....................................................................................15
3.3.2 Advertisement .....................................................................................16
3.3.3 Connection..........................................................................................16
3.3.4 Synchronization...................................................................................16
3.3.5 Measurement ......................................................................................17
3.3.6 Power saving.......................................................................................19
3.4 Magnetic Field Mapper................................................................................19
3.5 Firmware Update.......................................................................................20
3.5.1 Firmware update..................................................................................20
3.5.2 Firmware downgrade............................................................................20
3.5.3 Firmware compatibility .........................................................................21
4Output Specifications .............................................................. 22
4.1 Coordinate systems ...................................................................................22
4.1.1 Sensor coordinate system .....................................................................22
4.1.2 Orientation coordinate system ...............................................................22
4.1.3 Heading reset......................................................................................23
4.2 Sensors data outputs .................................................................................24

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4.2.1 Calibrated delta_q and delta_v ..............................................................24
4.2.2 Calibrated inertial data and magnetic field data .......................................24
4.2.3 Orientation..........................................................................................25
4.2.4 Free acceleration .................................................................................25
4.2.5 Timestamp and packet counter..............................................................25
4.2.6 Status ................................................................................................25
5Physical Specifications ............................................................ 27
5.1 Xsens DOT specifications............................................................................27
5.2 Sensor components specifications................................................................27
5.3 Battery specifications.................................................................................28
5.4 Sensor technical drawing............................................................................29
5.5 Charger technical drawing ..........................................................................30
6Important Notices ...................................................................31
6.1 Warranty and Liability................................................................................31
6.2 Customer Support .....................................................................................31
6.3 Product Compliance ...................................................................................32

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List of references
1. Xsens DOT Quick Setup Guide [XD0501P]
2. Xsens DOT SDK Programming guide for Android [XD0201P]
3. Xsens DOT SDK Programming guide for iOS [XD0202P]
4. Xsens DOT BLE Services Specifications [XD0506P]
5. Magnetic Calibration Manual [MT0202P]
List of Tables
Table 1: Power button function................................................................................ 8
Table 2: LED patterns ............................................................................................ 8
Table 3: Software supported platforms....................................................................10
Table 4: Filter profiles ...........................................................................................15
Table 5: Synchronization accuracy..........................................................................16
Table 6: Output rates............................................................................................17
Table 7: Firmware compatibility..............................................................................21
Table 8: Delta_q and Delta_v outputs .....................................................................24
Table 9: Inertial and magnetometer data outputs .....................................................24
Table 10: Orientation outputs ................................................................................25
Table 11: Free acceleration outputs ........................................................................25
Table 12: Status Definition ....................................................................................25
Table 13: Xsens DOT specifications.........................................................................27
Table 14: Orientation Performance .........................................................................27
Table 15: Gyroscope specifications .........................................................................27
Table 16: Accelerometer specifications ....................................................................27
Table 17: Magnetometer specifications....................................................................28
Table 18: Alignment specifications..........................................................................28
Table 19: Battery Specifications .............................................................................28
List of Figures
Figure 1: Xsens DOT sensors with a charger ............................................................. 6
Figure 2: Xsens DOT set......................................................................................... 7
Figure 3: Xsens DOT sensor.................................................................................... 7
Figure 4: Charger with power cable ......................................................................... 9
Figure 5: Mag Norm fluctuates when moving............................................................11
Figure 6: Mag Norm is constant while moving ..........................................................12
Figure 7: Xsens DOT signal processing architecture ..................................................14
Figure 8: Xsens DOT state transition diagram ..........................................................15
Figure 9: Root and scanners in synchronization ........................................................17
Figure 10: Xsens DOT sensor coordinate system ......................................................22
Figure 11: Heading reset/revert in Xsens DOT app....................................................23
Figure 12: Sensor technical drawing .......................................................................29
Figure 13: Charger technical drawing ......................................................................30

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1Introduction
Xsens DOT is a wearable sensor development platform features sensor incorporating 3D
accelerometers, gyroscopes and magnetometers to provide an accurate 3D orientation.
The embedded processor in the sensor handles sampling, calibration, strap-down
integration of inertial data and Xsens Kalman Filter core (XKFCore) algorithm for sensor
fusion. With wireless data transmission through Bluetooth 5.0, Xsens DOT can provide real-
time 3D orientation as well as calibrated 3D linear acceleration, angular velocity and (earth)
magnetic field data to a receiving device.
Xsens DOT is the start of a new Xsens product line bringing Xsens sensor solution to mobile
device platform. With simple-to-use SDK and comprehensive documentation, system
integrators can easily develop their wearable applications.
The Bluetooth Low Energy (BLE) data transmission, lightweight form factor and IP68 rating
widen the application areas of Xsens DOT, making it easy and durable to use in various
scenarios. Using different combinations of 5 sensors, it’s flexible to apply Xsens DOT to
customized measurement cases.
Fields of use:
1. Health and rehabilitation
2. Sports and exercise science
3. Ergonomics
Figure 1: Xsens DOT sensors with a charger

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2Getting Started
2.1 Xsens DOT set
A standard Xsens DOT set contains:
•5 Xsens DOT sensors
•1 charger with power cable
•Xsens DOT software package
Figure 2: Xsens DOT set
The easiest way to get started with Xsens DOT is to use Xsens DOT App (Android/iOS) to
connect the sensors. You can get to know the capabilities of Xsens DOT and to configure
the device according to your need. Refer to this unboxing tutorial to get started quickly.
2.2 Hardware
2.2.1 Xsens DOT
Xsens DOT sensor provides 3D angular velocity using a gyroscope, 3D acceleration using
accelerometer and 3D earth magnetic field using a magnetometer. Combined with Xsens
sensor fusion algorithms, 3D orientation and free acceleration are provided. With the
wireless nature of Bluetooth 5.0, Xsens DOT sensor is an excellent measurement unit for
tracking human body motions.
Figure 3: Xsens DOT sensor

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On top of the sensor is the LED giving the indications of sensor states. There is a power
button in the middle of the sensor to wake up, stop recording or power off sensor. The
micro-USB port at the bottom can be used to power on and charge the sensor.
NOTES:
•Sensor will always reboot when plugged in with a powered USB cable, no matter it
is ON or OFF.
2.2.2 Power button
Table 1 shows the functions of the power button.
Table 1: Power button function
Function
Power button pattern
Power OFF sensor
Long press over 3 seconds
Stop recording
Press for 1 second
Wake the sensor from power saving mode
Single press the button
Button callback function
If there is a single click on the power button during connection, a BLE notification will be
sent with a timestamp when this single click is applied. This function is called “Button
callback”. This is available in the Xsens DOT SDK or in the BLE Service Specifications
manual. Refer to those for additional information on the button callback.
2.2.3 LED status
Xsens DOT sensor has LED patterns to indicate different sensor states. Table 2 shows the
LED behaviors.
Table 2: LED patterns
State
LED Pattern
Power
ON/OFF
Powered off or power-saving mode
OFF
Sensor is being powered off
On for 1 second and fade out in 3
seconds
Measurement
Advertisement mode
Blink 1 time per second
Connection mode (not measuring)
Blink 1 time every 10 seconds
Real-time streaming mode
Blink 2 times every 10 seconds
Recording mode (including record,
export and clear data)
Fast blink 2 times and a short pause
Synchronization
OFF during sync period, all sensors
blink synchronously for 3 second if
sync succeeds.
Charging
Charging (battery full)
ON
Charging (75% <= battery < 100%)
Fade in/out, 4-second cycle
Charging (50% <= battery < 75%)
Fade in/out, 3-second cycle
Charging (25% <= battery < 50%)
Fade in/out, 2-second cycle
Charging (battery < 25%)
Fade in/out, 1-second cycle
Other states
Identifying sensor
Fast blink 8 times and a short pause

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Bootloader mode (reboot the sensor can
exit this mode)
Fast blink 2 times and a long pause
MCU/battery is overheated during
charging. Charging is stopped to protect
MCU and battery
Blink 8x per second
2.2.4 Charger
The charger is a docking station for 5 sensors and includes a plastic cover shell, along with
a USB power cable. You can open the charger by holding the cover shell and pull out the
docking from the right side.
Each docking slot features an embedded micro-USB port. Sensors can be charged by
plugging them in and out. Another micro-USB port placed on the right side of the Xsens
DOT charger is used to power on and charge all the sensors docked in the charger. To
power this micro-USB port, an adapter of 5V/300mA is enough but we would recommend
using a 5V/500mA adapter (5 sensor loads) based on standard USB 2.0 power supply.
Figure 4: Charger with power cable
2.2.5 Body straps and accessories
1
Xsens provides the Xsens DOT Strap Set as an attachment method to secure Xsens DOT
on the body. You can place Xsens DOT sensors inside the pocket of strap and wrap the
strap around the segment of interest. This will ensure good adhesion and fewer skin
artefacts. Refer to this BASE article for more information on sensor attachment.
In addition to this, a set of adhesive patches is available as an alternative attachment
method. These are recommended for clinical applications.
2.3 Software
As Xsens DOT serves as a wearable sensor development platform, we provide all the
software needed for different demands. The software package can be download here and
includes:
•Xsens DOT Software Development Kit (Android/iOS)
•Xsens DOT App (Android/iOS)
•Xsens DOT Server
•Xsens DOT Data Exporter
•SDK Documentations (Android/iOS)
1
Xsens DOT attachment solutions will be more diverse and flexible as we continue to improve

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•Xsens DOT SDK Programming guide for Android
•Xsens DOT User Manual
•Xsens DOT BLE Service Specifications
2.3.1 Supported platforms
Table 3: Software supported platforms
Software
Supported platforms
SDK and APK for Android
•Android OS 8.0 and above
•ARMv8 CPU architecture
SDK and App for iOS
•iOS 11.0 and above
Xsens DOT Server
•Windows 7, 10
•MacOS
•Raspberry Pi
Xsens DOT Data Exporter
•Windows 10
Bluetooth requirements
•Best performance with BLE 5.0, DLE2supported
•Compatible with Bluetooth 4.2
2.3.2 Choose your software
You can choose to use different software according to your demands. Please refer to the
following instructions on how to choose your software:
•If you focus on the motion data and want to quickly understand the data outputs
and capabilities of Xsens DOT, download and install Xsens DOT App. It will allow
you to:
oScan and connect the sensors
oData real-time streaming
oRecord data in sensor and export to other devices.
oFirmware update and other functions
Refer to these BASE articles for detailed guidance on Android App and iOS App
operations. Xsens DOT App tutorial video is also available.
•If you are a developer or system integrator who want to build your own applications,
download Xsens DOT Software Development Kit (SDK) for Android or iOS
applications. Refer to the SDK programming guide and the following example code
to get started:
oAndroid example: https://github.com/xsens/xsens_dot_example_android
oAndroid example: https://github.com/xsens/xsens_dot_example_ios
•If you are familiar with Bluetooth protocol and development, and you want to build
applications on any other platforms with Bluetooth 5.0, a lower level Xsens DOT
BLE Service Specifications is provided to enable direct communication with Xsens
DOT. For Windows or MacOS, an open-source project - Xsens DOT Server is
provided. You can download it from: https://github.com/xsens/xsens_dot_server.
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Data Length Extension

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2.4 Tips for best practice
2.4.1 Multiple sensors connection
Although there is no connection limit in Xsens DOT app, SDK or BLE services, hardware
and OS constraints of the central devices have a ceiling to the maximum number of sensors
that can be connected simultaneously. For Android, MacOS and Windows, it is possible to
connect up to 7 sensors. In iOS, Linux PC or Raspberry Pi, it is possible to connect up to
11 sensors. The actual connection capability highly depends on the devices you choose.
However, the BLE performance cannot be guaranteed if the connection limit is reached. If
big data loss or connection failure cases is observed, reduce the sensor connection number
or transmission payload.
2.4.2 Magnetic distortion
Ferromagnetic material (iron or steel), magnets or strong currents (several amperes) in
the environment near the sensor will cause disturbance to the magnetic field. The
magnetometer in Xsens DOT sensors is used as a 3D compass to determine the direction
of the Earth true north (heading or yaw), used as an absolute reference in the calculation
of 3D orientation. For detailed information about the influence of magnetic field on
orientation, see the PhD thesis “Inertial and magnetic sensing of human movement near
ferromagnetic materials” D. Roetenberg 2006. For best results when measuring with Xsens
DOT, it is advised to avoid highly magnetized areas when carrying out measurements,
particularly in the beginning.
To check the magnetic distortion, you can use the Xsens DOT App to check the Magnetic
Norm
3
in magnetic field data after connecting at least one DOT. Look at the Magnetic Norm
curve while moving in the measurement area.
•Areas for which the magnetic norm = 1 and the variation remains within ±0.2 are
magnetic homogeneous and best for carrying out the measurements (see Figure
5). However, if the measurement begins with a magnetic norm of around 2 or 3,
and remains within ±0.2 of this value, the orientation should remain accurate.
•If the Mag Norm will vary depending on the location and orientation of the device
(see Figure 6), there are magnetic distortions in the environment.
Figure 5: Mag Norm fluctuates when moving
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Magnetic Norm (Mag Norm) is the norm of all magnetic axis vectors (X, Y and Z) combined. It can
be used as an indication of magnetic distortions.

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Figure 6: Mag Norm is constant while moving
XKFCore algorithm running in the motion processor can compensate for the magnetic
disturbance caused by short or fast fluctuating disturbances by optimally using the
available sensor information and valid assumptions about the application. However, if the
disturbance is slow and large (>±0.2) or lasts for over 30s, it’s difficult for the algorithm
to compensate for and will influence heading accuracy.
If magnetic field norm has large fluctuations, or Xsens DOT sensor is attached to an
instrument or prosthesis that influences the magnetic field (e.g. ferromagnetic object), it
is best to carry out Magnetic Field Mapping for this DOT (see section 3.4) to recalibrates
the magnetometer.
NOTES:
•Never expose sensor to strong magnetic fields. The sensor contains the
absolute possible minimum of ferromagnetic materials. Nonetheless, some minor
components can be magnetized permanently by exposure to strong magnetic fields.
This will not damage the unit but will render the calibration of the magnetometers
useless, typically observed as a (large) deviation in the heading.
2.4.3 Cleaning method
To clean the Xsens DOT sensors and charger, use a moist cloth to wipe the surface.
2.4.4 Long-term storage guidelines
Execute the required firmware update
•Update the firmware to version 1.4.0 or above. Follow this guide to update the
firmware.
Storage conditions
Follow the recommended guidelines to preserve the battery life of the sensors:
•Operating temperature: 0°C - 50°C.
•Storage temperature: 25°C±10°C.
If the sensors will be stored for a prolonged period of 3 months or longer:
1. Charge all sensors to >90%.
2. Disconnect sensors from charger.

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3. Power off sensors through Xsens DOT App or pressing the power button over 3
seconds.
Recharge your Xsens DOT sensors every 3 months according to the recommended
guidelines to slow the rate of battery ageing thereby improving the battery shelf life.

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3Xsens DOT Overview
The signal processing architecture of Xsens DOT sensor is presented in Figure 7. Strap
down integration (SDI) and sensor fusion algorithm (XKFCore) are integrated into
firmware. You can get orientation increments and velocity increments from SDI, 3D
orientation and free acceleration from XKFCore. Xsens DOT sensor is factory calibrated,
making it more accurate repeatable and robust.
Figure 7: Xsens DOT signal processing architecture
3.1 Strapdown integration
Strap down integration is a method used to compute orientation and velocity increments
by integrating angular velocity from gyroscope and acceleration from the accelerometer.
The angular velocity and acceleration data are sampled and calibrated at a high frequency
(800 Hz) by the embedded MCU of Xsens DOT sensor to maintain accuracy under dynamic
movements such as running and jumping. Due to the high sampling frequency, the data
cannot be transmitted via Bluetooth directly and would typically present an excessive
computational load on the receiving host device (e.g., mobile phone). The SDI algorithm
receives the high-rate sensor input and processes it into a lower-rate signal at 60 Hz. The
main advantage of using the SDI algorithm is the accuracy is maintained, and information
is preserved to ensure precise orientation tracking.
The SDK data parser has built-in functions to convert SDI quantities to calibrated angular
velocity (rad/s) and acceleration (m/s2) data. Refer to data conversion sections in SDK
programming guides.
3.2 Sensor fusion algorithm and filter profiles
The 3D orientation of the sensor is computed by Xsens’ latest Kalman filter core algorithm
(XKFCore) for sensor fusion, which is optimized for human motions. It uses the output
from SDI to compute a statistical optimal 3D orientation estimate of high accuracy with no
drift for both static and dynamic movements. The XKFCore uses the measurement of
gravitational acceleration and Earth magnetic north to compensate for slowly increasing
errors from the integration of the rate of turn data and gives out free acceleration.

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As described above, the XKFCore makes assumptions on the range of acceleration and
magnetic field sensed to obtain orientation. Since those quantities can widely differ among
different user applications, multiple filter profiles are introduced to improve the orientation
estimation accuracy. As a result, the XKFCore is optimised to suit different types of
movements and applications. Find below additional information on the filter profiles
available to choose which is best suited for your application.
Table 4: Filter profiles
Name
Description
General
This filter profile is the default setting. It assumes moderate dynamics and a
homogeneous magnetic field. External magnetic distortion is considered
relatively short.
Dynamic
This filter profile assumes fast and jerky motions that last for a short time.
The dynamic filter uses the magnetometer for stabilization of the heading
and assumes very short magnetic distortions. Typical applications are when
sensors are applied on persons for sports such as sprinting.
3.3 Xsens DOT sensor state transition
Figure 8: Xsens DOT state transition diagram
3.3.1 Power ON/OFF
You can power on the sensor either with charger or a powered USB cable to plug in the
micro-USB port in the bottom. Sensor will go to advertisement mode after powered on.
Sensor will power off under 3 conditions:
1. Power button is pressed over 3 seconds
2. Receive power off command
3. Sensor will automatically shut down when battery level is lower than 2% to
prevent battery drain.

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3.3.2 Advertisement
In advertisement mode sensor will perform operation idle detection, waiting for BLE
connection from host devices. If no BLE connection is detected over 10 minutes
4
during
advertisement, sensor will enter power saving mode.
3.3.3 Connection
Once the Bluetooth connection is established, information such as MAC address, device tag
name, battery level and charging status... etc. can be retrieved from the sensor. In Xsens
DOT App, a reconnection will start automatically once the connection is lost.
If no measurement is started over 30 minutes
5
during connection, sensor will enter power
saving mode.
There is no sensor connection limit set in any software provided by Xsens. Though a max
5 sensors can be used for real-time streaming to guarantee a good performance of BLE
data transmission. Refer to section 2.4.1 for best practices on connecting multiple sensors.
3.3.4 Synchronization
Each sensor has its own clock domain. So, it is important to have the measurement data
time-synchronized between different sensors, especially in scenarios where multiple
sensors are required simultaneously, e.g., joint angles.
All the sensors will be time-synced to a common sensor time base after synchronization.
As the sensor clock drifts, the synchronization accuracy will decrease over time.
Table 5: Synchronization accuracy
Time
Accuracy
After 30 min
1 ppm
After 1 hour
4 ppm
A successful synchronization will take about 14 seconds. During the synchronization, one
sensor will be the root node, whereas the remaining sensors are scanners. The root node
will periodically send out advertisement messages while the scanners will receive the
messages and correct their own time domain by calculating the skew and offset of the root
clock.
To achieve a better synchronization result, it is advised to put the root node in a central
position of all the scanners. In Xsens DOT app, the first connected sensor will be the root
node. SDK users and other developers can set their own rules to choose the root node.
4
Default time threshold which can be changed in Xsens DOT App, SDK or by BLE services.
5
Default time threshold which can be changed in Xsens DOT App, SDK or by BLE services.

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Figure 9: Root and scanners in synchronization
Synchronization should take place before the measurement so that all the sensor data are
time-synced. After a synchronization, multiple measurements can be started and stopped
without additional synchronization. Refer to this BASE article for details about
synchronization in Xsens DOT app.
NOTES:
•Stop the synchronization after all the measurements to prolong the battery life.
3.3.5 Measurement
Two types of measurement are available with Xsens DOT. Table 6 shows the available
output rates for different types of measurement.
Table 6: Output rates
Measurement
Available output rates
Real-time streaming
1Hz, 4Hz, 10Hz, 12Hz, 15Hz, 20Hz, 30Hz and 60Hz
Recording
1Hz, 4Hz, 10Hz, 12Hz, 15Hz, 20Hz, 30Hz, 60Hz and 120Hz
By choosing lower output rates, less data per unit time will be transmitted when compared
to the standard 60Hz output rate. As a result, this can mitigate the occurrence of data loss
in Real-Time Streaming mode and less data will be stored, thereby recording time can be
extended. Conversely, higher output rate (120Hz) is better suited for high-dynamic
applications, where higher amount of data is needed. However, higher output rate is only
available for Recording mode.
Real-time streaming
In real-time streaming, motion data is streamed and logged to central device via constant
Bluetooth connection.
Sensor fusion data, inertial data and other custom data combinations are provided in real-
time streaming, together with packet counter and timestamp. Refer to Chapter 4 for data
output specifications.

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NOTES:
•To make data plot readable, orientation data will always be displayed in Euler
angles, whereas data in the log file will be stored in the chosen format (Euler or
quaternion).
•To make data plot readable, inertial data will always be displayed as acceleration
(m/s2) and angular velocity (degrees/s) whereas data in the log file will be stored
in the chosen format (high fidelity, delta quantities or rate quantities).
•Xsens DOT App allows for a maximum of 5 sensors for real-time streaming.
•Real-time streaming will continue even when Bluetooth connection is lost or App is
running in background. Stop the streaming after the measurement to prevent
battery drain.
High fidelity mode
High fidelity mode is available in real-time streaming. In this mode, Xsens proprietary data
format will be transmitted via Bluetooth and parsed in Xsens DOT App or SDK. The
advantage of this mode is that even in the case of transient data loss, higher frequency
(800 Hz) information is still preserved with lower output data rate (60 Hz).
High fidelity data will be parsed to delta_q, delta_v in Xsens DOT app. Functions to parse
high fidelity data to delta_q, delta_v or calibrated angular velocity and acceleration are
available in SDK. Refer to SDK programming guide for detailed information.
Recording
In recording mode, motion data is stored within the sensor internal storage and can be
exported for post-processing. Xsens DOT internal storage capacity enables to record for 88
minutes. In this mode, Bluetooth connection is not required once the recording is started.
Recording can be started and stopped using Xsens DOT App and these functionalities are
available in Xsens DOT SDK or BLE Service Specification manual.
Recording will stop in the following situations:
•power button is pressed for 1 second.
•time is up for timed recording sessions.
•flash memory is over 90%.
Data can be exported via Bluetooth or via USB connection. Wireless data transfer using
Bluetooth is suitable for exporting small files (a few minutes). When exporting large
amount of data, use Xsens DOT Data Exporter to export via USB on PC. Refer to this BASE
article on how to use Data Exporter.
As a rule of thumb, the time to export data via Bluetooth is twice the recording time, while
exporting via USB is 1/8. Note that export time highly depends on the files and the export
data quantities that you selected. When exporting data via Bluetooth, it is advised to select
few sensors at a time to prevent data transmission loss or connection failure. You can
choose different types of data configurations and select recording files when exporting.
Note that free acceleration is not included. For further information on how to calculate it
from other quantities, refer to this BASE article.

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3.3.6 Power saving
In power-saving mode, sensors will turn off the signal pipeline and BLE connection, put the
MCU in a sleep state to ensure minimum power consumption. In this state, sensors cannot
be discovered by host devices.
The default time thresholds to enter power saving mode is set to 10 min in advertisement
mode and 30 min in connection mode. Power saving mode can be disabled and the time
thresholds can be adjusted in Xsens DOT App, SDK or by BLE services.
Sensors will exit power saving mode when:
•Power button is pressed
•Acceleration is detected by accelerometer
Once the sensor enters power saving mode, you can wake it up by pressing the power
button or simply shaking it. Xsens DOT will return to advertisement mode when exiting
power saving mode.
3.4 Magnetic Field Mapper
When Xsens DOT sensor is mounted to an object that contains ferromagnetic materials,
the measured magnetic field can become distorted, causing errors in measured orientation.
To correct for known magnetic disturbances, Magnetic Field Mapper function has been
developed to allow users to remap the magnetic field of the sensor.
The MFM can be executed in a few minutes and yields a new set of calibration values that
can be written to the Xsens DOT’s non-volatile memory, which means it will not be erased
by powering off or firmware updates.
You can perform MFM with 5 sensors at the same time. Follow these steps to do the MFM
for Xsens DOT. Here is a detailed BASE article about how to do MFM in the App.
1. Open Xsens DOT App (Android or iOS)
2. Connect the target sensors
3. Go to Advanced →Magnetic Field Mapper
4. Select sensors to start MFM
5. Rotate the sensors slowly around all three axes and in all directions to collect data
for magnetic field calibration. The process automatically checks for data points that
are relevant and give sufficient coverage for a proper MFM procedure. The progress
bar indicates this and once the bar reaches 100%, MFM process will begin
automatically.
6. MFM is successful when showing “Finished”. Restart the MFM if it fails.
A .mtb file containing the calibration data will be created during the MFM. You can find it
in your mobile phone:
•Android: under this directory Android/data/com.xsens.dot.android/files/mfm
•iOS: Goto Files App →On My iPhone →Xsens DOT →mfm
NOTES:
•Stop the synchronization and set output rate to 60Hz before starting MFM.

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•The filter profile will be changed to general filter profile after MFM is done. This is a
known issue of FW1.6.0, which will be fixed in the next release. Before it is fixed,
after the MFM is done, please reset the filter profile to make it work.
3.5 Firmware Update
Continuous firmware releases from Xsens are scheduled to add new features,
improvements, and bug fixes. With Over-the-Air (OTA) firmware updates available in Xsens
DOT, you can easily update the sensors to latest version with Xsens DOT App.
NOTES:
•Make sure App is updated to the latest version first before carrying out the OTA.
•Sensors can only upgrade or downgrade when in charging status.
•Do not exit the update page or close the App during OTA.
•Network connection is required for OTA.
3.5.1 Firmware update
Once the sensor is connected, you can receive firmware update notifications if a new
version of firmware is available in Xsens DOT App. If no notification is received, the current
firmware version is up to date.
Follow these steps to perform a firmware update:
1. Put sensors in charging status
2. Open Xsens DOT App and connect the sensors you want to upgrade
3. Follow the notification badge, go to Advanced →Device Firmware Update,
choose Upgrade
4. Check available new firmware version, select sensors to upgrade
5. Check release notes and start upgrade
6. Check upgrade status after all upgrade is done. The sensor will automatically reboot
after firmware upgrade
7. Wait 10 seconds for sensor rebooting and then you can connect the sensors again
to experience the new firmware.
For SDK users, an interface is added in SDK to send out a notification if there is a new
firmware available. Thus, the applications developed with SDK can have an immediate
notification for a new firmware. Refer to Firmware update notification sections in the SDK
programming guides.
3.5.2 Firmware downgrade
Firmware downgrade function is provided to downgrade beta firmware versions to the last
stable version. However, if a new stable version is available, beta versions cannot rollback
to previous stable versions but instead the update to the subsequent stable version is
preferred. If downgrading to a previous firmware version is needed, contact technical
support.