Inertia ProMove-mini User Manual

ProMove-mini

Wireless Inertial Sensing Platform

User Manual

v3.7.0

Contents

1 Introduction 4

2 Safety instructions 5

3 Setup 6

3.1 System description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.2 Gateway connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.3 Node LEDs and button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.4 Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.5 Recharging the batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.6 On-board storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 Inertia Studio 10

4.1 Main screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.1.1 Toolbar and menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.1.2 Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.1.3 Information area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.2 Connecting to a device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.2.1 Connecting to a device using the toolbar . . . . . . . . . . . . . . . . 16

4.2.2 Connecting to a device using the menu . . . . . . . . . . . . . . . . . 17

4.3 Logging to file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.4 Logging to flash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.4.1 Starting and stopping a flash-log . . . . . . . . . . . . . . . . . . . . . 20

4.4.2 Downloading a flash log . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.4.3 Deleting flash logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.5 Filling in lost samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.5.1 Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.5.2 Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.5.3 Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.6 Exporting a logfile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.6.1 CSV Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.6.2 MAT Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.7 Replaying a logfile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.8 Configuring the sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.8.1 Global settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.8.2 Accelerometer settings . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.8.3 Compass settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.8.4 Gyroscope settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.8.5 Barometer settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

inertia-technology.com Page 2 of 60

4.8.6 High-G Accelerometer settings . . . . . . . . . . . . . . . . . . . . . . 36

4.8.7 Temperature settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

4.8.8 IMA settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4.8.9 RTC settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.8.10 Status settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.8.11 Sampling channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.9 Calibrating the Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.10 The Tracker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.11 Appearance and Preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.11.1 Layout wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.11.2 Global preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.11.3 Plot preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

4.11.4 Node preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

4.11.5 Orientation preferences . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.11.6 Tracker preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.11.7 FFT preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.12 Updating the firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

5 The orientation algorithm 54

6 Performing an Experiment 55

6.1 Experiment preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.2 Reading and aligning CSV log files . . . . . . . . . . . . . . . . . . . . . . . . 56

7 Troubleshooting 57

7.1 Finding the serial port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

7.2 Bluetooth connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

7.3 Slow signals in Inertia Studio . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

7.3.1 Lowering the plot update speed . . . . . . . . . . . . . . . . . . . . . 58

7.3.2 Reducing the number of plots or nodes . . . . . . . . . . . . . . . . . 58

7.3.3 Enabling hardware acceleration and multi-threaded rendering . . . . . 58

7.4 Retrieving an unreachable ProMove-mini Node . . . . . . . . . . . . . . . . . 59

7.5 Manually installing the Inertia Driver . . . . . . . . . . . . . . . . . . . . . . . 59

8 Technical Specifications 60

inertia-technology.com Page 3 of 60

1 Introduction

The ProMove-mini is a wireless inertial motion sensor node specifically designed for multi­person, multi-object motion tracking. A network can comprise tens of devices that sample and
transmit motion and orientation information at high data rates in a fully synchronized manner.

The ProMove-mini features a complete set of 3-D digital sensors, offering 10 DOF sensor data:
acceleration, turn rate (gyroscope), magnetic field intensity (compass), high-g acceleration and
barometric pressure. Full 3-D orientation information, expressed as quaternions, is also made
available to the user.

The sensor data is transmitted wirelessly using the low-power 2.4 GHz radio to a central node,
the Inertia Gateway, which connects to the computer through USB. Optionally, the sensor data
can be stored on the on-board flash and retrieved later over USB or wirelessly.

The number of nodes in the network scales with the sampling rates, e.g. a network can have
39 nodes that sample at 200 Hz, or 19 nodes that sample at 500 Hz.

Alternatively, the ProMove-mini can be equipped with a Dual-Mode Bluetooth module or a
Bluetooth 4.0 Low Energy module for direct communication to PCs, smartphones and tablets.

The ProMove-mini is carefully designed for good ergonomics. The curved design makes mount­ing and wearing on body parts comfortable, without affecting stability in case of surface mount­ing.

Figure 1: ProMove-mini sensor node

inertia-technology.com Page 4 of 60

2 Safety instructions

English

Operating temperature range: 0 - 35 °C

Maximum input voltage: 5V

Prevent contact with water.

Only connect to CE certified computers / USB-adapters.

Do not open the device.

Nederlands

Bedrijfstemperatuurbereik: 0 - 35 °C

Maximale ingangsspanning: 5V

Voorkom contact met water.

Maak alleen verbinding met CE gecertificeerde computers / USB-adapters.

Open het apparaat niet.

Deutsch

Betriebstemperaturbereich: 0 - 35 °C

Maximale Eingangsspannung: 5V

Verhindern Sie Kontakt mit Wasser.

Bitte nur CE-zertifizierte Computer / USB-Adapter anschließen.

Öffnen Sie das Gerät nicht.

Français

Gamme de températures de fonctionnement: 0 - 35 °C

Tension d’entrée maximale: 5V

Éviter le contact avec l’eau.

Seulement connecter à des ordinateurs / USB adaptateurs certifiés CE.

Ne pas ouvrir l’appareil.

inertia-technology.com Page 5 of 60

3 Setup

This section describes the high-level system setup.

3.1 System description

The default system consists of a number of ProMove-mini sensor nodes, the Basic Inertia Gate­way and Inertia Studio (PC Software) for monitoring and logging the inertial data. The standard
setup is depicted in Figure 2. The sensor nodes communicate wirelessly with the gateway in
the 2.4 GHz ISM band. The gateway is connected through the mini-USB connector with a PC
that runs Inertia Studio.

Figure 2: Typical system setup

A system could also consist of a single ProMove-mini node, which can be connected either
through micro-USB or through Bluetooth to the PC running Inertia Studio.

C++ and Java SDKs are available for developing custom applications that interact with Inertia
devices. The SDKs allow implementations on both desktop and mobile Android platforms.

inertia-technology.com Page 6 of 60

3.2 Gateway connections

Figure 3 shows the front and back of the Basic Inertia Gateway. The gateway has four blue

LEDs with the following functionality:

• RX: The gateway is receiving data.

• TX: The gateway is transmitting data.

• Power: The gateway is powered on.

• Sync: Not used.

The backside contains an antenna and a mini-USB connector.

Figure 3: The front and back of the Basic Inertia Gateway

3.3 Node LEDs and button

Figure 4 shows a ProMove-mini node and the reference system axes (X, Y and Z) to which the
on-board sensors are aligned.

The LEDs and the multifunctional button are located next to the micro-USB connector.

The green LED indicates the node is charging. The blue LED indicates the node is turned on
and sampling data. The blinking rate is determined by the sampling rate. The number of blinks
has the following meaning:

• Single blink: Not transmitting data.

inertia-technology.com Page 7 of 60

Figure 4: The ProMove-mini node and the reference X, Y and Z-axis

• Double blink: Transmitting data via USB or wireless. Synchronized nodes should blink at
the same time.

• Five blinks: Logging to flash memory.

The button has the following functionality:

• Pressing short once: Turns the node on; it is also used to confirm pairing via Bluetooth.

• Pressing short twice: Starts or stops logging to the flash memory.

• Pressing long once: Turns the node off. Pressing more than 5 seconds will powercycle
the node.

3.4 Attachments

Velcro straps can be attached through the handles, as shown in Figure 5.

3.5 Recharging the batteries

The internal battery of the ProMove-mini should be periodically recharged. This can be done
by using a cable connecting the micro-USB connector of the node to a computer or a standard
USB charger . A fully drained battery takes approximately 2 hours to recharge. During charging,
the green LED of the node is on. The gateway has no internal battery and therefore does
not require recharging. Monitoring the battery voltage can be done using Inertia Studio (see

inertia-technology.com Page 8 of 60

Figure 5: A ProMove-mini with a wristband

paragraph 4.1.3). The battery is fully charged around 4.15 V. When the battery is empty (at

3.45 V) the node will turn itself off automatically.

3.6 On-board storage

ProMove-mini nodes are equipped with 2 GB flash memory. Downloading the data from the
flash memory is described in Section 4.4.2.

The flash memory is used to store the following data:

• The sensor node configuration, including the global parameters, the wireless options
and the configuration of the sensors (for information about changing, storing and clear­ing the sensor node configuration, see Section 4.8).

• The sensor data, the sampled data of all enabled sensors. More information about stor­ing data in the flash memory of a sensor node can be found in Section 4.4. The flash
memory can store a maximum of 510 files.

inertia-technology.com Page 9 of 60

4 Inertia Studio

Inertia Studio can be used for realtime visualization of sensor data, logging of sensor measure­ments and pre-computed orientation, and configuration of sensor and wireless parameters.
This section describes Inertia Studio (v3.2.0) in more detail.

Inertia Studio is available for Microsoft Windows 7 and later. An (Ubuntu) Linux version can be
made available on request.

4.1 Main screen

Figure 6 shows the main screen of Inertia Studio, which is divided in the following areas:

• The menu and toolbar at the top (described in Section 4.1.1)

• The sensor data plots in the middle (described in Section 4.1.2)

• The information area at the bottom (described in Section 4.1.3)

In the following, these three areas are presented in detail.

Figure 6: Inertia Studio with six ProMove-mini nodes, showing data from the accelerometer,
compass and gyroscope

inertia-technology.com Page 10 of 60

4.1.1 Toolbar and menu

The toolbar is used to quickly access the most used functionality of Inertia Studio. This section
describes the default buttons of the toolbar, from left to right (see Figure 7).

Figure 7: Inertia Studio menu and toolbar

• Connect / Disconnect
The Connect / Disconnect button can be used to quickly connect to, or disconnect from an
Inertia device. The drop-down menu associated with this button opens a list for selecting
the target nodes. See Section 4.2 for more information.

• Record / Stop
When connected to a device, the Record / Stop button can be used to quickly start and
stop logging/recording to file (see Section 4.3). If timed recording is enabled, a small clock
overlay is shown on the icon. The drop-down menu associated with this button offers rapid
access to the Logging Configuration window (see Section 4.3). The user can also quickly set
the duration of the recording using time-presets.

• Pause / Resume
The Pause / Resume button is enabled during recording. It can be used to pause and resume
the recording.

• Sensor Settings
The Sensor Settings button opens the Sensor Settings window (see Section 4.8).

• Preferences
The Preferences button opens the Preferences window (see Section 4.11.3).

• Hide / Show
The Hide / Show button toggles between hiding and showing the data in the plots. The
drop-down menu associated with this button opens a list for selecting the target nodes for
which the data is hidden or shown. An small sign (i.e. red cross or yellow triangle) on the
icon indicates that some data is hidden. This button does not influence the logging.

• Clear (F5)
The Clear button, or F5, clears the plots, legend and node lists. This button does not influ­ence the logging.

• Layout
The Layout button opens the Layout Wizard (see Section 4.11.1).

inertia-technology.com Page 11 of 60

• Tracker
The Tracker button opens the Tracker window (see Section 4.10).

• Zoom In (F3) / Zoom out (F4)
The Zoom buttons, or F3 and F4, can be used to zoom the X-Axis of all plots in or out.

The menu allows access to all the options of Inertia Studio and has the following items:

• File
—Connect... opens the Connection Configuration window (Section 4.2).
—Record opens the Log to File (Section 4.3) and Log to Flash (Section 4.4.1) windows.
—Replay... opens the Replay window (Section 4.7).
—Download... opens the Download Logfiles window (Section 4.4.2).
—Fill-in Lost Samples... opens the Fill Loss window (Section 4.5).
—Export... opens the Export Logfiles window (Section 4.6).
—Exit closes Inertia Studio.

• Configuration
—Sensor Settings... opens the Sensor Settings window (Section 4.8).
—I/O Settings... opens the I/O Settings window (used by Advanced Inertia Gateway).
—Sensor Calibration... opens the Calibration Configuration window (Section 4.9).
—Preferences... opens the Preferences window (Section 4.11.2).
—File Types opens a sub-menu to configure the supported file types.
—Power Down... allows the user to remotely power down specific sensor nodes.

• View
—Layout Wizard... opens the Layout Wizard (Section 4.11.1).
—Tracker opens the Tracker window (Section 4.10).
—Detailed Status opens the Detailed Status window (paragraph 4.1.3).
—Toolbox can be used to show or hide the Zoom and Pan sliders, the RTC buttons and the
Log and Legend in the information area.
—Toolbar can be used to change the appearance of the toolbar. The toolbar can be hidden
using the Hide option. The size of the toolbar icons can be modified to Small, Medium and
Large. Show Text allows to show or hide the text below the icons. Show I/O Buttons adds
two extra buttons to the toolbar for I/O functionality.
—Show Data toggles between showing and hiding the incoming data in the plots.
—Clear Plots (F5) clears the plots, legend and node lists.
—Full Screen (F11) shows Inertia Studio in full-screen mode.

• Help
—Check for Updates checks if a new version of Inertia Studio is available, or if new firmware
for the connected nodes is available.
—Firmware Update... opens the Firmware Update window (Section 4.12).
—Software Web Site opens the Inertia Technology software website.

inertia-technology.com Page 12 of 60

—Manual (F1) opens the Inertia Studio manual.
—About shows the current Inertia Studio version and build date.

4.1.2 Plots

Inertia Studio can be configured to display a customizable number of plots that show in real­time the sensor data (e.g. accelerometer data), status data (e.g. battery voltage, lost samples)
and processed data (e.g. orientation, Norm, FFT). The shown plots and layout can be cus­tomized via the Layout Wizard (see Section 4.11.1). The X-axis of the time-plots represent the
number of seconds since the gateway was started.

The mouse can be used to zoom and pan the plot. Holding the left mouse button while moving
the mouse creates a zoom-box. Releasing the left mouse button zooms to the selected data.
Not that

Auto-scaling

resets the Y-axis zoom. A plot can be panned by holding the right mouse
button and moving the mouse. By default, the X-axis is automatically set to the latest received
data. Disable

Show Data

or use the pan slider (see Section 4.1.3) to prevent this.

Right-clicking on a plot provides the following options (see Figure 8):

Figure 8: Plot right-click pop-up menu

• Fit: Fits all received data in the plot.

• Zoom in/out: Zooms the plot in or out. The Zoom buttons in the toolbar and the Auto-
scaling option (see Section 4.11.3) can be used to reset the zoom.

• Lock X-axis...: Locks the X-axis to a specified range by showing a pop-up window in which
the minimum and/or maximum values of the X-axis can be set. When the axis is locked,
a ← and/or → symbol is shown at the bottom right and/or left corner of the plot. This
option is only enabled for FFT plots.

• Lock Y-axis...: Locks the Y-axis to a specified range by showing a pop-up window in which
the minimum and/or maximum values of the Y-axis can be set. When the axis is locked,
a ↑ and/or ↓ symbol is shown at the left top and/or bottom corner of the plot. Locked
plots do not auto-scale.

• Auto-Scale Y-axis: Toggle automatically scaling the Y-axis. This overrules the global auto-
scaling option in Section 4.11.3.

inertia-technology.com Page 13 of 60

• Save as SVG...: Save the plot as a SVG image.

4.1.3 Information area

The information area at the bottom of the main screen shows the list of event messages and the
legend with connected nodes. In addition, a zoom-slider, a pan-slider and buttons to set and
get the time of the nodes can be added to the information area via the menu (View, Toolbox).

Notification Area

Event notifications are displayed in the notification area. They give information about the out­come of certain actions, such as connecting to or disconnecting from a device, starting or stop­ping logging, downloading or exporting files, modifying sensor configurations, etc. By clicking
the header of the time column, the notifications can be sorted in ascending or descending
time order. Right clicking an item in the list provides the following options: copy the selected
line(s), copy all lines, and clear the notification area.

The icon in front of a message indicates the notification type. A green check-mark means
success, a red cross means error, an orange triangle means warning and a blue circle means
information.

Legend

The legend contains a list of all the nodes of which sample data is received. The first column
shows the selected port, the line colour and node ID for each node. The node ID can be ex­tended with a name in Section 4.11.4. The second column (Signal) displays the radio signal
strength (when connected via a gateway), or the transmission type (in case the node is con­nected via USB or Bluetooth). The third column (Battery) shows the battery level for each node,
and whether the node is charging. The fourth column (Loss) shows the percentage of lost sam­ples over the last period (see also Section 4.11.2). The fifth column (Flash) shows whether the
node is logging to flash or not. The legend can be sorted by every column. Double-clicking on
the legend opens the Detailed Status window (see paragraph 4.1.3).

The radio strength is updated every second. The battery level is, by default, updated every
ten seconds. The loss update interval can be configured via the global preferences (see Sec­tion 4.11.2).

Zoom, Pan and RTC

The zoom and pan sliders can be used to change the visible data in the plots. The zoom slider
behaves the same as the zoom buttons in the toolbar (Section 4.1.1) and allow to zoom the
X-axis in or out. The pan slider allows the move back in time and show older data. The max-

inertia-technology.com Page 14 of 60

imum number of seconds to pan can be configured in the global settings (Plot History in Sec­tion 4.11.2). If panning is active, plots are not updated with new sample data.

The RTC buttons can be used the set and get the time of the Real-Time Clock of a node. The
RTC is also set automatically when a node is discovered by Inertia Studio. When setting the
time, the current UTC time of the PC is send to the nodes.

Detailed Status

The Detailed Status Overview window (see Figure 9) can be accessed by double clicking an item
in the legend or via the View menu, sub-menu Detailed Status. The window shows detailed
information about the battery level, CPU temperature, RSSI and sample loss of the connected
nodes. The plots are cleared when (re)connecting to a device.

Figure 9: Detailed Status information

The battery and temperature plots are updated when status information from a node is re­ceived via automatic status messages (usually every ten seconds). The RSSI plot is updated
every second with the average value of the received RSSI information. The sample loss plot
is updated every second with the detected sample loss. The time on the X-axis is the system
time. A battery is fully charged when the voltage is around 4.15 V. The node powers down
when the voltage drops below 3.45 V.

A checkbox is available to disable automatic updating of the plots. This can be used to prevent
the plots from resetting when zoomed in. The Send Request button broadcasts a message to
all nodes with a request to send the current battery and CPU temperature value.

inertia-technology.com Page 15 of 60

4.2 Connecting to a device

In this section we describe how an Inertia device can be connected to the PC, using the follow­ing connections:

• USB: Any Inertia device can be connected to the PC using USB. The micro-USB connector
of the ProMove-mini and the mini-USB connector of the gateway can be used for direct
connection to the PC using a USB cable.

• Bluetooth: A ProMove-mini node with Bluetooth can be connected wirelessly using
Bluetooth to the PC. See Section 7.2 on how to pair with a Bluetooth device.

The connection can be started via the Connect button in the toolbar or from the File menu

item, option Connect....

4.2.1 Connecting to a device using the toolbar

Pressing the arrow next to the Connect button in the toolbar opens the drop-down menu
shown in Figure 10:

• The option Connect... opens the Connection Configuration window, which is explained
in Section 4.2.2.

• The option Available... opens a pop-up window with all the available devices.

• Below the line, a list is shown with the names of the available Inertia devices connected
through USB or Bluetooth. Next to them, the corresponding port numbers are given. A

• symbol in front of the name indicates the device is selected. A ► symbol in front of
the name indicates the device is connected.

Select the desired device and press the Connect button in the toolbar to connect.

Figure 10: Connect drop-down menu

inertia-technology.com Page 16 of 60

4.2.2 Connecting to a device using the menu

The option Connect... from the File menu item opens the Connection Configuration window
from Figure 11. The window shows a list with Stored Configurations, i.e. all the connections
to Inertia devices that were previously used and those that are currently available. The list in­cludes the devices connected through USB or Bluetooth. The port name (“com*“ on Windows
and “/dev/*“ on Linux) is shown next to the device name. A green dot indicates the device is
available. The ► symbol indicates the device is connected.

By pressing the Available? button, the list is updated and a pop-up window with all the avail­able devices is shown. The Add... button can be used to manually add a device to the list if it is
not automatically detected. The Remove button removes a selected device from the list. The
Connect/Disconnect button starts/stops the connection with the device.

Figure 11: Connection Configuration

inertia-technology.com Page 17 of 60

4.3 Logging to file

When connected to an Inertia device, the incoming data can be stored/recorded in a log file.
The default file format is itlog (Inertia Log File). Incoming samples, node information and con­figurations, etc, are stored in the file. An itlog file can be exported to CSV or MAT format
(see Section 4.6). The itlog format also supports filling in lost samples after an experiment is
finished, see Section 4.5.

There are two options that can be used to enable logging to file:

1. By using the Record button from the toolbar; to change the settings for creating a log
file, select the Log to File... option from the drop-down menu of the Record button; this
option opens the Logging Configuration window for logging to file (see Figure 12).

2. By selecting the Log to File... option from the File menu, Record item; this option opens
the same Logging Configuration window for logging to file (see Figure 12).

Figure 12: Log to File Configuration

In the Logging Configuration window, the settings for creating a log file can be modified as
follows:

• Filename: The name of the log file. The default file format is itlog.

• Description: A description that can be added to the beginning of the (exported) log file.

inertia-technology.com Page 18 of 60

• Compression: An optional compression format used for the log file, resulting in a smaller
file size. Supported compression methods are: gzip (.gz, GNU Zipped Archive), bzip (.bz2,
BZIP2 Compressed Archive) and zlib (.Z, UNIX Compressed Archive).

• Unique Filename: Selects the way of handling existing log files with the same name:

– Overwrite: The existing file is overwritten.

– Append to File: The data is added to the existing file.

– Auto-Number: Files are numbered in sequence with the following naming convention:

<filename>[_№].ext, where ext is the file extension and № is the sequence number;
this number is automatically increased every time a log file with the same name is
created.

– Date in Filename: The current date and time are added to the filename; the timestamp

is formatted as described in ISO 8601 (i.e. [YYYYMMDDThhmmss_]<filename>.ext).

• Stop Logging After: This option can be enabled to automatically stop logging to file. The
duration can be entered as hh:mm:ss. When active, a countdown is shown in the toolbar.

• Start Flash Logging: Starts (and stops) logging to flash when a log file is created. This option
is enabled by default when Fill-in Lost Samples is enabled.

• Fill-in Lost Samples: Fills-in lost samples when logging to file is finished (see Section 4.5).

• Export: Exports the log file when logging to file (including filling in lost samples) is finished.
The button opens the Section 4.6 window.

If a device is connected, the Record button can be used to save the settings and start creating a
log file. If the device is disconnected, the Save button can be used to save the current settings.
The Stop button can be used to stop logging. During logging, the Pause and Resume buttons
can be used to pause, respectively resume, logging to file. These buttons behave similarly to
the buttons in the toolbar (i.e. Record / Stop and Pause / Resume), described in Section 4.1.1.

inertia-technology.com Page 19 of 60

4.4 Logging to flash

ProMove-mini nodes have an internal flash memory that can be used to store sensor data.
Flash logs are used to fill in lost samples after an experiment, as described in Section 4.5. Flash
logs can also be created manually, as described in Section 4.4.1. Section 4.4.2 describes the
way the flash logs can be downloaded to the PC.

4.4.1 Starting and stopping a flash-log

The Log to Flash option from the File menu, Record item, opens the Logging Configuration
window for logging to flash (see Figure 13).

The Logging Configuration window shows the list of all devices in the network. For each node
in the list, the ► symbol indicates whether the node is logging to flash or not. If a timer is used
when starting the flash log (the Stop Logging After option is enabled), a countdown is visible
in the list. The last column in the list shows the sensor data types that are logged to flash (see
Section 4.8 to enable or disable sensors).

Figure 13: Log to Flash Configuration

The Start / Stop buttons can be used to send a command to the checked node(s) to start or stop
logging to flash. The Stop Logging After option activates a timer for stopping the flash logging.
Closing Inertia Studio while a timer is active does not determine a node to stop logging to flash.

inertia-technology.com Page 20 of 60

The format of the timer is hh:mm:ss. During logging to flash, the blue led blinks in short bursts.
Starting or stopping a flash log can also be done by pressing shortly twice on the button of the
ProMove-mini (see Section 3.3).

When starting or stopping a flash log, a notification message appears in the information area at
the bottom of the main screen with the response from the node, indicating success or failure.
A failure can occur when logging to flash is already started (or stopped) or when the maximum
number of 510 files is reached.

Flash logs are named LOG<№>.LOG, where № is the first available number starting from 1.
The creation date of the flash log is also recorded. The date is based on the internal clock
of the node. If the battery of a node is fully drained, the clock is reset, which can result in
an incorrect creation date. The internal clock is automatically synchronized with the PC time
when data from a node is received by Inertia Studio.

A ProMove-mini sampling at 200 Hz with all sensors enabled uses about 20 MB of flash per
hour.

4.4.2 Downloading a flash log

To download flash logs, the node should be directly connected via an USB cable to the PC.
Downloading over radio/Bluetooth is supported, but is generally much slower and could fail
due to packet-loss. By selecting the Download... option from the File menu, the Download
Flash Logs window appears, as shown in Figure 14. When a node is selected in the drop-down
list, status information about the internal flash is shown, and the File list is updated with the
flash logs present on the internal flash of the node. The filename, file-size and creation date
(local time) of each file is shown in the list. Selecting a node or using the Refresh button on the
right hand side will update the status information and file-list. Active files (e.g. files currently
being created) are not included in the file list.

To download a file, select it in the File list and adjust the following options:

• Destination: The name of the file (itlog format). Several wildcards are supported in the
filename:

– {name} or %s: Insert the full flash file name (without extension).

– {no} or %d: Insert the number of the flash file (e.g. 34 for LOG34.LOG).

– {date} or %c: Insert the creation date of the flash file (in ISO 8601 format).

– {id} or %i: Insert the node ID.

• Unique Filename: Selects the way of handling existing log files with the same name (same
as in Section 4.3).

• Use Date from Flash File: Set the creation date of the file to the date of the flash file.

inertia-technology.com Page 21 of 60

• Export: Export the file when downloading is finished (see Section 4.6).

Press Download to start the download. If the node is transmitting data, transmission will be
temporarily disabled until the download is finished.

During downloading, the progress is shown in the list. Information about the progress is also
shown in the information area at the bottom of the main screen (see paragraph 4.1.3). When
downloading is in progress, the Cancel button can be used to cancel the process. If a file is
being downloaded, other files of the node can be queued so they will start downloading as
soon as the current file is finished. Select one or more files, adjust the file options, an press
Queue.

Figure 14: Download Flash Logs

4.4.3 Deleting flash logs

Flash logs can be removed from the flash memory using the Format button in the Download
Logfiles window (Figure 14). This action removes all files from the internal flash memory. For-

matting takes about 5 to 10 seconds. A message is shown when formatting is finished.

Do not turn the nodes off during formatting!

inertia-technology.com Page 22 of 60

4.5 Filling in lost samples

When performing an experiment with wireless sensor nodes, there is almost always some data
loss. This loss can be filled in automatically after the experiment is finished. The sections below
explain this process.

4.5.1 Automatic

Enable Fill-in Lost Samples when creating a logfile (see Section 4.3). Once logging is stopped,
a pop-up is shown informing that missing data will be filled in. Once continued, the Fill-in Lost
Samples window is shown (Figure 15) and missing data is automatically filled in.

The process consists of three stages:

1. First, the existing logfile is analyzed and missing data of each node is identified. During
this stage, a progress bar for each node is filled with blue bars. The tint of the color rep­resents the amount of lost data: white is 100% loss, dark blue is 0% loss. The percentage
inside the progress bar is the total percentage of samples available.

2. During the second stage, the missing data is requested wirelessly from the nodes (Fig­ure 15). The progress bars are actively being updated to reflect the received data. The
lighter segments change to dark-blue.

3. In the third stage, the received data is merged into the itlog file (Figure 16). The progress
bars are filled with green bars to show the progress. If there is still some missing data,
sections in a progress bar are made red and messages with information about the miss­ing sections are added to the notification area. A manual restart could fill in the remain­ing missing samples (see Section 4.5.2).

Figure 15: Requesting Figure 16: Merging

Once the process is finished, and if Export was enabled when the logfile was created, the file
is exported in the background. If the fill-loss process is canceled using the Cancel button, a
pop-up asking to continue with export is shown.

inertia-technology.com Page 23 of 60

The Fill-in speed during the second stage is dependent on the configured number of nodes in
the network (Section 4.8.1). The value should be close to the actual number of nodes, e.g. 6
or 9 (default) when using 6 nodes.

4.5.2 Manual

Filling in lost samples can also be started manually. Open the window via the menu (File, Fill-in
Lost Samples...) and expand the manual settings using the Manual Settings arrow (Figure 17).

Provide the following parameters:

• File: The itlog file to be filled in.

• Port: The port used to access the node(s), usually the port of the gateway.

• Export: Export (Section 4.6) the itlog file when filling in lost samples is finished or canceled.

• Backup: Keep a backup of the unfilled file (named <filename>_BACKUP_.itlog).

Use Start to start the process.

Figure 17: Manual settings

4.5.3 Details

Details

The

arrow can be used to expand the window and show a list with all the status mes-

sages that have appeared. The items in the list can be copied or cleared using the Copy and

Clear

buttons. The

Auto-scroll

checkbox can be used to enable or disable automatic scrolling

of the list to the latest message.

inertia-technology.com Page 24 of 60

4.6 Exporting a logfile

Inertia Log Files of type itlog can be exported to different file types using the Export Logfiles
window (see Figure 18), which can be accessed from the menu (File, Export). The following
parameters can be modified:

• Source: The itlog file(s) to export. The Destination filename is automatically updated to
match the source name and the selected file format.

• Format: The file format to export the itlog file to. Settings specific to the file format can be
modified via the Configure button.

• Compression: An optional compression format used for the exported file, resulting in a
smaller file size. Supported compression methods are: gzip (.gz, GNU Zipped Archive), bzip
(.bz2, BZIP2 Compressed Archive) and zlib (.Z, UNIX Compressed Archive).

• Unique Filename: Selects the way of handling existing log files with the same name (same
as in Section 4.3).

Use the Start button to save the settings and export the file(s). Active and previously exported
files are shown in the Activity List. Double-clicking an item opens the exported file in its default
program. An active item can be canceled using the Cancel button. previously exported files
in the activity list can be cleared using the Clear button. The folder of a selected item can be
opened using the Open Folder button.

Figure 18: Export Logfiles

inertia-technology.com Page 25 of 60

4.6.1 CSV Settings

Inertia Log Files can be exported to a Comma Separated Values file (CSV). The CSV Settings can
be modified in the CSV Settings window (see Figure 19), accessible via the menu (Configuration,
File Types, CSV Settings...) or from the Export window.

A CSV file starts with a header identifying each column. Each subsequent line in the CSV file
consists of a timestamp and the sensor data sampled at that timestamp.

The following settings can be modified for the CSV file format:

• One File per Node: A separate file is created for each node; the node number is appended
to the filename: <filename>[_node№].ext. When disabled, one file with data from all nodes
is created.

• Repeat Previous Value: When sensors have a lower sampling rate than the global sampling
rate, empty values are added to the CSV file (no value between commas). For example,
when the global rate is 200 Hz, the compass samples at 100 Hz, resulting in empty values
every other line. By using this option, instead of logging an empty value, the last received
value is repeated until a new value is received.

• Add Info to Beginning of File: Add information such as node information, sensor settings,
units of measurement, a description, etc, to the beginning of the log file. The information
lines start with a #.

The sensor data added to the CSV file can be configured by (un)checking the desired Columns.
Default columns for ProMove-mini, V-Mon 4000 and All can be loaded using the Defaults but-
tons. Apply will save the settings and close the window, Close will discard any modified settings
and close the window.

Figure 19: CSV Settings

inertia-technology.com Page 26 of 60

4.6.2 MAT Settings

Inertia Log Files can be exported to a MatLab MAT file. The MAT Settings can be modified in
the MAT Settings window (see Figure 20), accessible via the menu (Configuration, File Types,
MAT Settings...) or from the Export window.

The MAT file contains a global structure array with a field for each node structure. Each node
structure contains four fields. Field columns contains the column names and indices of the
columns, fields combines multiple columns into one field (e.g. ax, ay and ax into accelero­meter), data contains the sensor data, and samplingRate contains the sampling rate.

The following settings can be modified for the MAT file format:

• Struct Name: The name of the global structure array.

• MAT Version: The MAT-file version (see MatLab documentation).

• MAT Compression: Enable compression of the MAT file.

• No. of Samples: The number of samples in the MAT file. This option is not relevant when
exporting an itlog file to MAT. Only when logging directly to a MAT file, the number of sam­ples to store needs to be known beforehand. If more (or less) samples are logged, these are
ignored (or filled with NaN).

The sensor data added to the MAT file can be configured by (un)checking the desired Columns.
Default columns for ProMove-mini, V-Mon 4000 and All can be loaded using the Defaults but-
tons. Apply will save the settings and close the window, Close will discard any modified settings
and close the window.

Figure 20: MAT Settings

inertia-technology.com Page 27 of 60

4.7 Replaying a logfile

The Replay Logfile window can be used to replay a previously created logfile. It has the follow­ing options:

• Logfile: The logfile that will be replayed.

• Hardware Type: The hardware type of the device used in the logfile. This is necessary
to determine to correct initial orientation in the tracker. Only required when replaying
a csv file.

• Sampling Rate: The sampling rate used in the logfile. This is used to calculate the Read
Interval (below) and for calculating FFTs. Only required when replaying a csv file without
information header.

• Number of Nodes: The number of nodes in the logfile. This is used to calculate the Read
Interval.

• Read Interval: The interval in microseconds at which samples in the logfile are added to
the plots. The initial value is determined by the Sampling Rate and Number of Nodes,
but the interval can be manually adjusted. During a replay, the slider can be used the
change the speed of the replay.

• Rewrite Replay Log: The logfile will be rewritten to a new file (same name, with -replay
appended), and the orientation (Euler angles and/or quaternions) will be (re)calculated.

A replay is started with the Play button, and stopped with the Stop button. During the replay,
it can be paused with the Pause button. The buttons in the toolbar can also be used to control
the replay. Replays are added to the drop-down menu of the Connect button. Finished replays
are removed from the drop-down menu when the Available... option is used.

Figure 21: Replay Logfile

inertia-technology.com Page 28 of 60

4.8 Configuring the sensors

The Sensor Settings window can be used to modify the configuration of Inertia nodes. This

window is accessible via the toolbar and via the Configuration menu, item Sensor Settings....

Once a device is connected, the configuration options of the detected Inertia nodes is shown
in this window.

Figure 22: Sensor Settings

Figure 22 shows the Sensor Settings window, which is divided in the following areas:

• The node list area, marked with green in Figure 22, contains the list of devices available
via the currently selected connection. When a node is selected, its configuration options
are shown in the sensor tree. When a node is checked by using the checkbox beside it,
the actions of the buttons refer to this node. In Figure 22, all nodes are checked, so the
configuration is applied to all these nodes after pressing the

• The sensor tree, marked with red in Figure 22, shows the available configuration op­tions of the selected nodes in the node list. When choosing an option in the tree, the
corresponding configuration settings are shown in the settings panel. The different con­figuration options in the sensor tree are discussed in the subsequent sections.

inertia-technology.com Page 29 of 60

Apply Settings

button.

• The buttons, marked with blue in Figure 22, have the following functions:

– Refresh This button can be used to request all the configurations from all nodes.

The purpose is to make sure that configurations are successfully applied and cor­rectly retrieved by Inertia Studio.

– Store This button stores the current configuration of the checked nodes in their

flash memory, so the settings are retained when the nodes are turned off. The
button is not visible if configurations are automatically stored (Section 4.11.2).

– Restore This button can be used to restore all the configurations of the checked

nodes. The nodes are reset to their factory-default settings.

– Apply Settings This button applies all the modified settings (shown bold in the sen-

sor tree) to the checked nodes in the list. If no settings are modified, the currently
shown settings are applied If settings are stored automatically, a 15 second count­down is shown.

– Close This button closes the window, discarding all modified settings.

• The settings panel, marked with yellow in Figure 22, shows the settings available for
the selected configuration option of the selected node in the node list. These settings
are discussed in detail in the subsequent sections. When invalid or not recommended
settings are used, these settings are marked with a red (invalid) or orange (not recom­mended) colour. Invalid settings cannot be applied. Error, warning and information
messages are shown below the Apply Settings and Close buttons. The settings panel
also contains a Refresh and Restore button at the top-left corner. These buttons can be
used to refresh or restore the selected configuration of the selected node.

4.8.1 Global settings

By selecting the Global configuration option from the sensor tree, the global settings can be
edited, as shown in Figure 23:

• Transmit Data: Data transmission can be switched off by unchecking the check-box. Nodes
keep sampling (i.e. to store data in the flash memory).

• Sampling Rate (Hz): Selects the sampling rate used by the sensors. Some sensors may be
limited to a lower sampling rate. When using Synchronous sampling mode, the default max­imum number of nodes supported by the network for a selected sampling rate is shown on
the right. The maximum sampling rate is 1000 Hz.

• No. of Nodes: The number of nodes in the network to which the device is currently con­figured. For gateways this can be modified to match the configuration of the node(s). For
nodes this is automatically changed to match the gateway settings.

inertia-technology.com Page 30 of 60

• Sampling Mode: Inertia nodes can be configured to Synchronous or Stand-alone sampling.
When sampling synchronously, the gateway dictates the time when the nodes take a sample.
Nodes will not take samples until a gateway is detected. In stand-alone mode, each node
decides on its own when to take a sample.

• Transmit Type: Data can be transmitted using Wireless (Radio or Bluetooth), USB or both.

• Frequency Channel: Selects the frequency channel used by the Radio. To establish a con­nection, the channel of the nodes has to be the same as the channel of the gateway. When
changing channel, it is recommended to first change the frequency channel of the nodes,
and then the channel of the gateway.

Figure 23: Global Settings

inertia-technology.com Page 31 of 60

4.8.2 Accelerometer settings

By selecting the Accelerometer configuration option from the sensor tree, the accelerometer
settings can be edited, as shown in Figure 24:

• Enabled: Enables sampling of the accelerometer.

• Transmit Data & Log to Flash: If the accelerometer is enabled, data is transmitted and logged
to flash when required (see Section 4.8.1 for global transmission settings and Section 4.4.1
to start a flash log).

• Sampling Rate (Hz): The sampling rate of the accelerometer (maximum 1000 Hz).

• Range (g): Sets the maximum acceleration that can be measured. Supported options are:
±2, 4, 8 and 16 g. A lower range has a higher sensitivity.

• Calibration: Advanced option that adjusts the scaling and offset of each axis (see Section 4.9
for details about the calibration method).

Figure 24: Accelerometer Settings

inertia-technology.com Page 32 of 60

4.8.3 Compass settings

By selecting the Compass configuration option from the sensor tree, the compass settings can
be edited, as shown in Figure 25:

• Enabled: Enables sampling of the compass.

• Transmit Data & Log to Flash: If the compass is enabled, data is transmitted and logged to
flash when required (see Section 4.8.1 for global transmission settings and Section 4.4.1 to
start a flash log).

• Sampling Rate (Hz): The sampling rate of the compass (maximum 100 Hz).

• Range (gauss): Shows the maximum magnetic induction that the compass can measure,
which is ±49 gauss.

• Calibration: Advanced option that adjusts the scaling and offset of each axis (see Section 4.9
for details about the calibration method).

Figure 25: Compass Settings

inertia-technology.com Page 33 of 60

4.8.4 Gyroscope settings

By selecting the Gyroscope configuration option from the sensor tree, the gyroscope settings
can be edited, as shown in Figure 26:

• Enabled: Enables sampling of the gyroscope.

• Transmit Data & Log to Flash: If the gyroscope is enabled, data is transmitted and logged to
flash when required (see Section 4.8.1 for global transmission settings and Section 4.4.1 to
start a flash log).

• Sampling Rate (Hz): The sampling rate of the gyroscope (maximum 1000 Hz).

• Range (°/s): Sets the maximum rotational velocity the gyroscope can measure. Supported
options are: ±250, 500, 1000 and 2000 °/s. A lower range has a higher sensitivity.

• Calibration: Advanced option that adjusts the scaling and offset of each axis.

Figure 26: Gyroscope Settings

inertia-technology.com Page 34 of 60

4.8.5 Barometer settings

By selecting the Barometer configuration option from the sensor tree, the barometer settings
can be edited, as shown in Figure 27:

• Enabled: Enables sampling of the barometer.

• Transmit Data & Log to Flash: If the barometer is enabled, data is transmitted and logged
to flash when required (see Section 4.8.1 for global transmission settings and Section 4.4.1
to start a flash log).

• Sampling Rate (Hz): The sampling rate of the barometer (maximum 25 Hz).

• Range (hPa): Sets the pressure range the barometer can measure, which is 260-1260 hPa.

• Calibration: Advanced option that adjusts the scaling and offset.

Figure 27: Barometer Settings

inertia-technology.com Page 35 of 60

4.8.6 High-G Accelerometer settings

By selecting the Acclerometer (High G) configuration option from the sensor tree, the high-g
accelerometer settings can be edited, as shown in Figure 28:

• Enabled: Enables sampling of the high-g accelerometer.

• Transmit Data & Log to Flash: If the high-g accelerometer is enabled, data is transmitted
and logged to flash when required (see Section 4.8.1 for global transmission settings and
Section 4.4.1 to start a flash log).

• Sampling Rate (Hz): The sampling rate of the high-g accelerometer (maximum 1000 Hz).

• Range (g): Sets the maximum acceleration the high-g accelerometer can measure. Sup­ported options are: ±100, 200 and 400 g. A lower range has a higher sensitivity.

• Calibration: Advanced option that adjusts the scaling and offset of each axis.

Figure 28: High-G Accelerometer Settings

inertia-technology.com Page 36 of 60

4.8.7 Temperature settings

By selecting the Temperature configuration option from the sensor tree, the temperature sen­sor settings can be edited. The settings for the temperature sensor are not related to the CPU
temperature from paragraph 4.1.3. The settings are shown in Figure 29:

• Enabled: Enables sampling of the temperature sensor.

• Transmit Data & Log to Flash: If the temperature sensor is enabled, data is transmitted
and logged to flash when required (see Section 4.8.1 for global transmission settings and
Section 4.4.1 to start a flash log).

• Sampling Rate (Hz): The sampling rate of the temperature sensor (maximum 1000 Hz).

• Range (°C): Sets the temperature range the temperature sensor can measure, which is -40­85 °C.

• Calibration: Advanced option that adjusts the scaling and offset.

Figure 29: Temperature Settings

inertia-technology.com Page 37 of 60

4.8.8 IMA settings

ProMove-mini is able to calculate IMA (Integral of the Modulus of the Accelerometer) mea­surements. Figure 30 shows the IMA Settings, with the following parameters:

• Enabled: Enables calculating IMA measurements (note that the Accelerometer should also
be enabled).

• Transmit Data & Log to Flash: If IMA measurements are enabled, data is transmitted and
logged to flash when required (see Section 4.8.1 for global transmission settings and Sec­tion 4.4.1 to start a flash log).

• Sampling Rate (Hz): The sampling rate at which data for the IMA measurements is collected
(maximum 1000 Hz).

• IMA Interval (s): The time in seconds at which an IMA measurement is calculated.

• Values per Message: The number of IMA measurements to send at once.

Figure 30: IMA Settings

inertia-technology.com Page 38 of 60

4.8.9 RTC settings

ProMove-mini is able to sample the Real Time Clock (RTC). The RTC is sampled as epoch time­stamp (number of seconds since 01-01-1970). Note that the RTC is not synchronized between
nodes. The RTC of a node is synchronized to the PC time (±1s) when a node is detected by
Inertia Studio. Figure 31 shows the RTC Settings, with the following parameters:

• Enabled: Enables sampling of the RTC.

• External Triggered: Sample the RTC when an IMA sample is taken.

• Transmit Data & Log to Flash: If RTC sampling is enabled, data is transmitted and logged to
flash when required (see Section 4.8.1 for global transmission settings and Section 4.4.1 to
start a flash log).

• Sampling Rate (Hz)/(s): The sampling rate at which the RTC measurements are collected,
either for every sample (Hz), or at the provided interval in seconds.

Figure 31: RTC Settings

inertia-technology.com Page 39 of 60

4.8.10 Status settings

By selecting the Status configuration option from the sensor tree, the settings for status sam­ples can be modified. Status samples consist of the battery level, CPU-temperature and exter­nal input detection (e.g. whether USB is plugged in). Figure 32 shows the Status Settings, with
the following parameters:

• Enabled: Enables the status samples.

• Interval (s): The interval in seconds at which status samples are transmitted (between 10s
and 60s).

Figure 32: Status Settings

inertia-technology.com Page 40 of 60

4.8.11 Sampling channels

ProMove-mini uses sampling channels for each enabled sensor. Figure 33 shows a summary
of the used sampling channels. For each active sampling channel, it shows:

• Channel: The channel number assigned to the sensor.

• Sensor: The name of the sensor that uses the channel.

• Wordsize (bit): The size in bits of one value.

• № Values: The number of values in a sample.

• Conversion: The factor to convert a raw measurement to unit. Values are separated with
semicolon if they have different conversion factors.

Figure 33: Sampling Channels

inertia-technology.com Page 41 of 60

4.9 Calibrating the Sensors

This section describes how to calibrate the accelerometer and compass of the ProMove-mini.

First create a logfile as described in Section 4.3. While logging, rotate the node(s) a few times
very slowly around all three axes, at distance from any metal object. For the accelerometer,
make sure that all three axes reach -9.8 to 9.8 m/s2. A logfile of 30 s should suffice. For the
accelerometer, all nodes can be stacked and calibrated at once. For the compass, it is recom­mended to calibrate only one node at a time, to minimize the influence from other nodes.

Open the Calibration Configuration shown in Figure 34 via the menu (Configuration, Sensor
Calibration...). Browse to the calibration logfile created earlier and click Parse File. The file is
analyzed, calibration results are calculated, and detected nodes are added to the Node ID box.

Select a node and sensor and press Calibrate to calculate the required Scale and Offset for each
axis. A plot is shown to show the effect of the scale and offset on the normalized sensor signal.
The scale and offset can be applied to the node by pressing Use Results. The calculated values
are loaded into the Calibration settings of the sensor and node in the Sensor Configuration
window (Section 4.8). Press Apply Settings in this dialog to apply the settings to the node.

Note: Calibrating and applying results has to be done for each node and sensor separately. In
general, the calculated scale should be around 1 and the offset around 0. If not, the calibration
source file is likely invalid (e.g. no rotation around the y-axis).

Figure 34: Calibration Configuration

inertia-technology.com Page 42 of 60

4.10 The Tracker

The Tracker window (see Figure 35) can be accessed from the toolbar or via the menu View,
item Tracker. It shows the graphical real-time representation of the orientation of one or more
sensor nodes, calculated by the orientation algorithm.

A specific node to track can be selected from the Node drop-down list. Tracking multiple nodes
at the same time can be done by selecting the All option from the drop-down list. The View
drop-down list allows changing the 3D appearance of the tracked sensor nodes, as follows:

• Normal: The nodes are shown as coloured boxes.

• Model: The nodes are shown as 3D models of the ProMove-mini. The colour of the
model matches to colour of the node in the legend. A custom model can also be used,
see Section 4.11.6 for more information.

• Arm: The nodes are shown as coloured boxes, bound together as arm segments.

The slider can be used to zoom in or out. Several aspects of the tracker are configurable in the
Preferences window, see Section 4.11.6.

Figure 35: Tracker with six ProMove-mini nodes

inertia-technology.com Page 43 of 60

4.11 Appearance and Preferences

The appearance of the plots can be changed via the Preferences and the Layout Configuration
Wizard windows.

The Layout Configuration Wizard window is accessible from the toolbar and via the menu View,

item Layout Wizard.... Section 4.11.1 describes how this option can be used to change the type

and number of plots that are shown in the main screen.

The Preferences window is accessible from the toolbar and via the menu Configuration, item

Preferences.... The four tabs of the Preferences window are described in the following sections.

After any modification of the preferences, press the Apply button to apply them. Press the
Close button to discard all changes.

4.11.1 Layout wizard

The layout wizard makes it easy to quickly switch between layouts, or to make a custom screen
layout. Simply select one of the predefined layouts from the list and press the Finish button.
The relevant layouts for ProMove-mini are:

• 9D: Plots of the accelerometer, compass and gyroscope sensors for all three axes.

• 9D+: Plots of the accelerometer, compass, gyroscope and high-g accelerometer sensors
for all three axes, and plots for the pressure, battery, temperature and RSSI measure­ments.

• Empty Screen: No plots are shown.

• Custom Layout: The number of plots, the type of sensor data and the location on the
main screen can be chosen by the user.

Figure 36 shows the layout wizard set for Custom Layout. The number of visible rows and
columns can be changed via the up and down buttons. Each plot type can be changed by press­ing the corresponding Change button. The Plot Selection window appears, allowing the selec­tion of a different plot type. When the Only show available sensors selection box is checked,
the window shows only the available sensor types of the connected nodes. Otherwise, the
window shows all the available plot types.

Processed data can also be shown in the plots. Available options include the following:

• Norm: The normalized value of the axes of a sensor (i.e.

√

x2+ y2+ z

2

).

• Orientation: The orientation of the node, in terms of Euler angles (i.e. roll, pitch and
yaw, including FFT values) or quaternions.

• FFT: The Fast Fourier Transform, which can be applied to raw sensor signals or processed
data (see Section 4.11 for changing the FFT settings).

inertia-technology.com Page 44 of 60

The Y-axis label of each plot can be modified, with the constraint that it must be unique. By
pressing the yellow arrow, the label resets to its default value.

Figure 36: Layout Wizard with custom layout and Plot Selection window

inertia-technology.com Page 45 of 60

4.11.2 Global preferences

In the Global tab, the following preferences can be edited:

• Small Icons in Legend: Shows small or large icons in the legend.

• Automatically Check for Updates: Checks every week if a new version of Inertia Studio
is available.

• Store Sensor Settings Automatically: Automatically stores the sensor settings perma­nently on the node(s), 15 seconds after applying.

• Automatically Open Export Window: Open the Export Logfiles window (see Section 4.6
when an Export starts.

• Show Network Adapters: Shows the network adapters that can be used to connect to
an Advanced Inertia Gateway via Ethernet.

• Down Sampling: A number of samples can be averaged before showing them in the
plot. This improves performance, but shows a flattened signal. Down sampling cannot
be applied to FFT plots and has no effect on the values in the log files.

• Sample Loss Interval (s): Sets the interval in seconds used for the accumulation of lost
samples and calculation of the sample loss percentage, shown in the legend.

• Plot History (s): Sets the maximum number of seconds of data to show in the plot (visible
when panning the plot).

• Register File Extensions: Registers the itlog and fwu (firmware update file) file exten­sions to Inertia Studio.

Figure 37: Global Preferences

inertia-technology.com Page 46 of 60

4.11.3 Plot preferences

In the Plot tab, the following preferences can be edited:

• Auto Scaling on Y-axis: Automatically adapts the limits of the Y-axis to the minimum and
maximum value of each plot.

• Show X-axis Grid: Shows grid lines on the X-axis (vertical lines).

• Show Y-axis Grid: Shows grid lines on the Y-axis (horizontal lines).

• Enable Anti-Aliasing: Enables anti-aliasing to smoothen the plots.

• Show Gaps when Samples are Lost: When samples are lost, show a gap in the plot
instead of connecting the points directly.

• Multi-Threaded Rendering: Uses multiple threads to render the plots.

• Hardware Acceleration: Uses the graphics card of the PC to draw the lines in the plots.
Select which rendering method to use.

• Background Colour: Changes the colour theme to a black background with white axes,
or a white background with black axes.

• Update Speed: Modifies the speed at which the plots are updated. Setting the slider
closer to Slow increases the performance on a slow or overloaded PC (e.g. when showing
many plots or many nodes).

Figure 38: Plot Preferences

inertia-technology.com Page 47 of 60

4.11.4 Node preferences

In the Node tab, the following preferences can be edited:

• Node number: Selects a node number for changing its preferences.

• Description: A description of the selected node that will be shown in the legend. The
yellow arrow will clear the description.

• Line colour: Selects the colour to use in the plots for the selected node. The yellow
arrow will reset the colour to the nodes default colour.

• Reset for All Nodes: Resets the colour and description of all nodes to their default values.

Figure 39: Node Preferences

inertia-technology.com Page 48 of 60

4.11.5 Orientation preferences

In the Orientation tab, the following preferences can be edited:

• Enable Orientation Calculation: Enables calculating the orientation.

• Use Compass: Uses data from the compass for orientation calculation.

• Use High-Pass Gyroscope Filter: Uses a high-pass filter for the gyroscope to reduce yaw­drift. If the gyroscope is in rest, very small gyroscope measurements (< 4*resolution) are
ignored.

• Reset Orientation in Rest: Resets the orientation when the node stops rotating.

• Initial Yaw Angle (°): Sets the initial yaw angle (irrelevant when compass is enabled).

• Algorithm: Select the algorithm to use to calculate the orientation quaternions.

Figure 40: Orientation Preferences

inertia-technology.com Page 49 of 60

4.11.6 Tracker preferences

In the Tracker tab, the following preferences can be edited:

• Show Node Numbers: Shows the node number next to the 3D model.

• Show Angles: Shows the Euler angles (roll, pitch, yaw) in the tracker. In the Tracker
window, only one node should be selected.

• Show Wireframe: Shows the 3D model as a wireframe.

• Show Axes: Shows the axes of the ground plane.

• Use Custom Model: Chooses a custom 3D model to show instead of the ProMove-mini
model. The model should be in Wavefront .obj format1. After loading, the 3D model is
centered and scaled to fit in the tracker.

• Background Colour: Changes or resets the background colour of the tracker.

• Model Size: Increases or decreases the size of the 3D model.

Figure 41: Tracker Preferences

1

The .obj file should start with three-coordinate vertices followed by three-elements faces. The easiest
method to create these files is using MeshLab. First, open or import the model. Then go to the File menu and se-

lect Export Mesh (As).... Select Alias Wavefront Object (*.obj) as filetype. In the next window, deselect everything

(or select None) and press OK.

inertia-technology.com Page 50 of 60

4.11.7 FFT preferences

In the FFT tab, the following preferences can be edited:

• Window Function: Selects the window function used by the FFT algorithm. The available
options are: Rectangular, Triangular, Hamming, Hanning and Blackman.

• X-axis Scale: Selects the scale of the X-axis as a linear or a logarithmic scale (in decibel).

• Y-axis Scale: Selects the scale of the Y-axis as a linear or a logarithmic scale (in decibel).

• FFT Points (2ˆ): The number of samples used as input for a FFT calculation (2

• FFT Interval: The number of samples between subsequent FFT calculations.

• Remove DC: Reduce the 0-component by removing the mean DC signal.

FFT Points

).

Figure 42: FFT Preferences

inertia-technology.com Page 51 of 60

4.12 Updating the firmware

Figure 43 shows the Firmware Update window. It can be accessed from the Help menu.

The Firmware Update window can be used to update the firmware of the selected device,
either using USB or wireless.

Information about the selected device, including its node number, hardware type and revision,
and the version number of the current firmware is shown in the Device Info box. Specific
firmware options of the device, such as IMA, Bluetooth or customer specific firmware, are
also shown.

Figure 43: Firmware Update

When a firmware update file (*.fwu) is selected, the information of the file is shown in the File
Info box. This includes the hardware type and revisions supported by the firmware update file,

and the version of the update file.

If no firmware is selected, the device can be reset to its factory defaults by checking Reset to
Factory Defaults, and pressing Reset. After resetting, the device has to be manually restarted.

inertia-technology.com Page 52 of 60

The Progress box shows information about validating, uploading and reprogramming. When
a node is connected and a file selected, Validating... shows whether the file is valid and if the
supported hardware matches the connected hardware. If valid, the Upgrade button will be en­abled. Once the button is pressed, Uploading... shows the progress of uploading the firmware
to the device. If uploaded is successfully, the device will be disconnected and the Reprogram-
ming... progress will show a countdown timer. When finished, the device is reconnected and
the new firmware information should appear in the Device Info box.

Do not disconnect or turn off the device during reprogramming!

Depending on the firmware version of the device and the version of the firmware file, the but­ton will Downgrade, Reprogram or Upgrade the firmware. Reset to Factory Defaults will clear
the current settings and load the default settings of the new firmware once reprogramming is
finished. This reset can also be forced by the firmware update file. In this case, the checkbox
can not be modified.

If the firmware update resets the sensor settings, the wireless channel will also be reset to the
factory settings. After a successful update, if the gateway and the sensor node are on different
wireless channels, the sensor node becomes unreachable. For changing the wireless channel
of an Inertia device, See Section 4.8.1.

Firmware update does not work if the device does not have internal flash memory, if the in­ternal flash memory is full or when the maximum number of files is reached (510).

inertia-technology.com Page 53 of 60

5 The orientation algorithm

The orientation algorithm uses inertial sensor data (accelerometer and gyroscope, optionally
compass) to calculate the orientation of a node. This is represented in quaternions and Euler
angles. The initial roll and pitch angles relative to the Earth’s gravitational field are instan­taneously determined using the accelerometer. The yaw angle relative the Earth’s magnetic
field is determined by the compass. If the compass is not enabled, the initial yaw provided in
Section 4.11.5 is used. Every new inertial sample is combined with the current orientation to
calculate the new orientation. The order for Euler angle rotations is ZYX.

For the best performance, the accelerometer and compass should be calibrated as described
in Section 4.9. An uncalibrated accelerometer can cause a slight change in the roll or pitch
angles while the node is lying flat. An uncalibrated compass can cause an incorrect yaw angle
or strange jumps in the yaw angle.

There are two situations that have to be considered with respect to the usage of the compass:

• The compass is used. Please note that the compass is highly influenced by the surrounding
metal objects and electromagnetic fields and therefore it is in general not useful indoors.
To be used indoors, the node has to be at least one meter away from any metal object
and elevated at least one meter from the ground. In this case, the compass needs to be
calibrated (see Section 4.9).

• The compass is not used. In this case, the nodes start with the same initial yaw angle, which
can be configured from Preferences -> Orientation (Section 4.11.5). The computation of the
orientation using the compass has to be disabled. There are two options for doing this:

– Deselect the option Use compass from Preferences -> Orientation (Section 4.11.5).

– Disable the compass sensor from Sensor Settings (Section 4.8.3).

At the beginning of an experiment, it is recommended to reset the initial orientation of the
algorithm by using the Reset button in the Tracker window (Section 4.10). In this way, all nodes
will start with the correct initial yaw angle.

inertia-technology.com Page 54 of 60

6 Performing an Experiment

This section describes how to perform and experiment and how to read and align the data
obtained from the experiment.

6.1 Experiment preparation

In order to perform an experiment and to collect data synchronized from multiple nodes, the
following steps should be followed:

• Connect the gateway (Section 4.2).

• Check the settings of the gateway (Section 4.8.1).

• Turn on the nodes and verify that data is received from all of them (make sure they are
on the same channel as the gateway); verify packet loss and battery level in the legend
(paragraph 4.1.3).

• Check the settings of the nodes regarding enabled sensors and sampling rates (Section 4.8).

• Calibrate the sensors if necessary (Section 4.9).

• Reset the orientation using the Reset button in the Tracker (Section 4.10). In this way, all
nodes will start with the correct initial yaw angle.

• If logging to flash is required (e.g. when filling in lost samples), check the already existing
flash logs and perform a format for each node if necessary (Section 4.4.3).

• Open the Logging Configuration window and check the settings regarding location of file
and other options (Section 4.3)

• If Export is enabled, check the export settings (Section 4.6) and file settings, e.g. CSV Settings
(Section 4.6.1).

• Start recording from Logging Configuration window or from the toolbar.

• Stop recording from Logging Configuration window or from the toolbar; this step is not
necessary if a countdown timer was used (Section 4.3).

• If enabled, confirm and wait for lost samples to be filled in (Section 4.5). In case of missing
data (red sections appear in the progress bar), expand the manual settings and press Start
to restart the process (Section 4.5.2).

• If enabled, wait for file to be exported (Section 4.6).

inertia-technology.com Page 55 of 60

6.2 Reading and aligning CSV log files

268.5 269 269.5 270 270.5 271 271.5 272 272.5 273 273.5

−20

−10

0

10

20

30

40

Aligned acceleration data from multiple nodes

Timestamp [s]

Acceleration [m/s

2

]

Node 1
Node 2
Node 3

Each line in the log file consists of a timestamp and sensor data sampled at that timestamp. A
timestamp is the time in decimal seconds since the gateway was started. Figure 44 shows an
example log file containing timestamps and sensor data from an experiment.

Figure 44: Example of a log file

It is important to align the data from multiple nodes based on the timestamps. In a plot show­ing sensor data from multiple nodes, the timestamps should always represent the x axis. Fig­ure 45 shows an example of acceleration data from multiple nodes aligned based on time­stamps.

Please note that logs from multiple nodes can have different number of samples because the
nodes started and stopped at slightly different times, different sampling rates, lost samples,
etc. This is not important, as long as the sensor data is aligned based on the timestamps.

Figure 45: Example of aligned data from multiple nodes based on timestamps

inertia-technology.com Page 56 of 60

7 Troubleshooting

7.1 Finding the serial port

The serial port used by an Inertia node has to be specified in Inertia Studio, as described in
Section 4.2. In this section, we give an example of how to find the active serial port in Windows
7, 8 and 8.1.

Go to the Control Panel and open Devices and Printers. A list of all connected devices appears,
as shown in Figure 46.

Figure 46: Devices and Printers with a ProMove-mini Node

The serial port identifier is shown in the device name (COM70 in Figure 46).

If for some reason the identifier is not present in the device name, right click on the device,
select Properties, and then select the Hardware tab. The port identifier is mentioned in the
Name column of the Device Functions list.

inertia-technology.com Page 57 of 60

7.2 Bluetooth connection

Make sure that Bluetooth is enabled on the PC. Go to Control Panel and open Devices and
Printers. Select Add a device. The Bluetooth devices within the range of the computer should

appear in the list.

Enabled ProMove-mini Nodes should appear in the list. Double-click on the device, or click
Pair, to connect to it. When asked to compare pass-codes, select Yes and click Next to con­tinue. Next, press the on/off button of the ProMove-mini Node once in order to complete
the pairing.

If a secure connection is established, a serial port will be assigned to the Bluetooth device. The
device will appear in Inertia Studio, as described in Section 4.2. The serial port number can be
obtained as described in Section 7.1.

Generally, Bluetooth devices remain available until they are unpaired in the operating system.

7.3 Slow signals in Inertia Studio

When using multiple nodes, it is possible that the signals in Inertia Studio are displayed slower,
and the software may start to lag. This is likely to be caused by drawing the plots, which is quite
CPU-intensive. The following options are available to increase the performance.

7.3.1 Lowering the plot update speed

The Update Speed of the signals in Inertia Studio can be lowered and the averaging for the
Down Sampling can be increased, as described in Section 4.11.2 and Section 4.11.3.

7.3.2 Reducing the number of plots or nodes

The layout wizard can be used the decrease the number of shown plots (see Section 4.11.1).
Decreasing the number of plots lowers the load on the CPU. Reducing the number of nodes
that are plotted at once (see Figure 4.1.1) can also improve performance.

7.3.3 Enabling hardware acceleration and multi-threaded rendering

Enabling hardware acceleration (see Section 4.11.3) will, in general, improve the performance
by delegating some of the calculations to the GPU. Using multiple threads to render the plots
reduces the load of the main thread and improves responsiveness of the user interface.

inertia-technology.com Page 58 of 60

7.4 Retrieving an unreachable ProMove-mini Node

If during network reconfiguration the communication with one node is lost and reconnection is
not possible using the procedures described earlier in this manual, please refer to the following
steps for node recovery:

1. Connect the node directly to the computer with a micro USB cable.

2. Click the Capture item from the File menu and select the serial port associated with the
node from the drop-down list. Press the Start button.

3. Open the Configuration window from the Options menu and select Global in the sensor
tree (see Section 4.8.1). Check the channel number. Change the channel if this doesn’t
match the configuration of the gateway. Transmit Data must be enabled for this node.
A mismatch of the sampling rate can also result in sensor data missing in Inertia Studio.
Note that unless the transmit type is set to USB, the data cannot be captured and shown
directly from a wired node.

7.5 Manually installing the Inertia Driver

If you are unable to install the Inertia Driver via the provided installer, the driver can be installed
manually. The following steps describe this procedure for Windows 7, 8 and 8.1.

1. Connect the Inertia node to the PC. Windows tries to find the correct driver, but fails.

2. Go to Devices and Printers (from the Start Menu or Control Panel), right click on the
Inertia node, and select Properties.

3. Select the Hardware tab. There should be three items, two times ProMove-mini Node
and one time USB Composite Device. Select USB Composite Device and select Properties.

4. If not in administrator mode, select Change Settings in the General tab, then go to the
Driver tab and select Update Driver….

5. Select “Browse my computer for driver software”, select “Let me pick from a list of device
drivers on my computer”.

6. A list with compatible hardware is shown. If it contains the latest Inertia Driver, select
it. Otherwise, select Have Disk… and browse to the location of the driver file (inertia.inf,
on the CD in the drivers/files folder). Select OK and Next.

7. Windows installs the driver. If the “Windows can’t verify the publisher of this driver
software” is shown, select “Install this driver software anyway”. On Windows 8 and 8.1,
this requires Driver Signature Enforcement to be disabled.

inertia-technology.com Page 59 of 60

8 Technical Specifications

Accelerometer

Range Selectable: ±2, ±4, ±8, ±16 g
Resolution 62 µg @ ±2 g range
Sampling rate 1000 Hz
Non-linearity ±0.5 %
Cross-axis ±2 %
Noise power spectral density 300 µg/√Hz

Gyroscope

Range Selectable: ±250, ±500, ±1000, ±2000 °/s
Resolution 0.007 °/s @ ±250 °/s range
Sampling rate 1000 Hz
Non-linearity ±0.1 %
Cross-axis ±2 %
Rate noise spectral density 0.01 (°/s)/√Hz

Compass

Range ±4912 µT
Resolution 0.15 µT
Sampling rate 100 Hz

Barometer

Range 260 to 1260 hPa
Resolution 0.02 Pa
Sampling rate 25 Hz
Pressure noise 0.01 hPa RMS

High-g accelerometer

Range Selectable: ±100, ±200, ±400 g
Resolution 49 mg @ ±100 g range
Sampling rate 1000 Hz

Inertia Wireless Network Protocol

Frequency band 2.4 GHz
Data rate 4 Mbps
TX power 10 dBm
Range 20 m line-of-sight

Data collection and storage

Maximum number of nodes
in a single network

Inertia Gateway Central hub for synchronized data collection
Synchronization among nodes < 100 ns
Wired interface USB 2.0 full-speed compatible
Storage 2 GB flash

Software

Inertia Studio

Electrical characteristics

Battery life 4 h in full streaming mode

Miscellaneous

Bluetooth (optional) 4.0 dual-mode BR/EDR/BLE
Attachments Strap attachment
Dimensions 51 x 46 x 15 mm
Weight 20 g (including battery)

39 nodes at 200 Hz each
19 nodes at 500 Hz each
9 nodes at 1 kHz each

Real-time visualization, data acquisition and configuration
Runs on Windows 10, 8, 7, Vista, Ubuntu Linux

inertia-technology.com Page 60 of 60