The movement sensors.
In this section, you will find practical guidance on how to use, calibrate, and collect data with the sensors. Accurate and consistent use of the equipment ensures that we can reliably capture changes in participants’ movement behaviour before and after the intervention.
Why do we use sensors?
As part of the intervention, participants will wear lightweight sensors that record acceleration and segment orientation during daily activities. This helps the research team understand whether an enriched environment leads to increased or more varied movement in the upper limb - an important indicator of motor recovery.
Participants wear sensors on four locations: chest, non-affected forearm, and both the upper arm and forearm of the affected limb.
steps – what to do
No light. Sensor is switched off.
Blinking orange light. Sensor is on but not collecting data.
Blinking green light. Sensor is actively collecting data.
Steady green light. Sensor is on the charging dock.
Turning on and off
To turn on
Press and hold the button above for approx. 2 seconds. Light turns green, then orange.
To turn off
Press and hold the same button for approx. 3 seconds until the light goes off. Sensors also turn off automatically after 2 hours of inactivity.
First-time setup.
Before using the sensors for the first time, you need to activate them, download the app, and perform a magnetometer calibration. This only needs to be done once.
1
Activate the sensors
Place the sensors on the charging dock before first use. This activates them and ensures they are ready for data collection.
2
Download the app
Download the app on the provided phone using the QR code for Android (Google Play) or iOS (App Store).
Quick links
3
Connect sensors to the app
Open the app. It will scan for sensors automatically. Toggle on each sensor to connect it. You need all sensors connected for calibration.
4
Perform magnetometer calibration (MFM)
In the app, go to the Advanced tab → Magnetic Field Mapper.
Ensure Sensor Configuration is set to 60 Hz.
Select all sensors, press Start MFM, and slowly rotate the sensor box in all directions until calibration is complete (each sensor shows "Finished").
This calibration is recommended for the most accurate results and only needs to be done once when activating the sensors for the first time.
Placing the sensors on the participant.
Sensors must be placed correctly to the best of their ability. Insert each sensor into its case/pouch with the grey side facing the skin, then attach the straps.
Strap around the chest. Sensor positioned on the sternum, below the breast plate.
Sensor in alignment with the hand, as if the arm were placed flat on a table.
Sensor at the mid-point between the shoulder and elbow.
Sensor on the forearm, in alignment with the hand.
Sensors must be placed correctly each day. Insert each sensor into its case/pouch with the grey side facing the skin, then attach the straps.
Collecting data.
Use the PH Data Collection app on the provided laptop to sync the sensors and start recording. Do this together with the participant at the start of each session.
1
Open the PH Data Collection app
Find and open the "Ph Data Collecti..." app icon on the laptop desktop.
2
Turn on the sensors
Turn all sensors on (orange blinking light = on, not collecting). Place them close to the laptop.
3
Select "Sensors are On! Continue"
The app will search for the sensors. The dialogue will show how many are found.
4
Confirm all 4 sensors are found
Select "Yes" when the app shows "We found 4. Is this the correct amount?" If not all 4 appear, see FAQ below.
5
Place sensors on the participant and start recording
Attach the sensors as described in Section 3. Then select "Sensors placed. Start data collection." Sensors should now show a blinking green light — they are recording.
Data collection duration
Data collection runs for 2 hours. If you need to stop earlier, select "Stop data collection" in the app. A sound will play and the sensors will shut down automatically when the session ends. If a blinking light remains, turn the sensor off manually.
Uploading and clearing the data.
After each session, export the recorded data from the sensors using the PH Data Exporter app and then clear the sensor memory.
1
Open the PH Data Exporter app
Find the "PH Data Exporter" icon on the laptop desktop and open it.
2
Connect sensors and scan
Use the charging cable to connect the sensors to the laptop. Select "Scan All Ports". All sensors should appear. If not, wait a few seconds and scan again.
3
Select the correct files
Within each sensor, select the file that matches today's session. Use the file name format: first 6 numbers = date (YYYYMMDD), last 6 = time (HHMMSS). Select all relevant files and press "Confirm".
4
Export the data
Repeat Step 3 for all sensors. Then press "Export". Files are saved to the Data Folders shortcut on the laptop.
5
Clear the sensor memory
After exporting, use the "Clear" button for each sensor in the app. Wait until no files remain available — this confirms the memory is cleared. This prevents data loss in future sessions.
FAQ
Common troubleshooting issues and how to resolve them.
Select "No" and the app will try to find the sensors again.
Ensure all sensors are in the "on and not collecting data" state (orange blinking).
If this doesn't work, select "Cancel everything", turn sensors off and on again, and restart the process.
Make sure all sensors are within 30cm of the laptop and in the orange blinking state.
Restart the PH Data Collection app and try again.
If the problem persists, contact the research team.
Data collected up to that point is still valid. Note the time the sensor stopped and log it in the phone log. Ensure sensors are fully charged before the next session.
Document which sensor could not be placed and why. Contact the research team for guidance on how to proceed. Do not skip the session — partial data is still valuable.
Log the missed session in the phone log. Use it as an opportunity to problem-solve with the participant – are the sensors uncomfortable? Is the routine unclear? Adjust accordingly.