biosignalsplux Electrodermal Activity (EDA) Sensor User Manual

biosignal acquisition tool-kit for advanced research applications
Electrodermal Activity (EDA) Sensor User Manual
Electrodermal Activity (EDA)
User Manual

ATTENTION

Please read this datasheet before using your biosignalsplux sensor
The information contained in this document has been carefully checked and were made every effort to ensure its quality. PLUS reserves the right to make changes and improvements to this manual and products referenced at any time without notice.
The word Bluetooth and its logo are trademarks of Bluetooth SIG Inc. and any use of such marks is under license. Other trademarks are the property of their respective owner.
Please check your systems and sensors after receiving and before using them the first time to confirm if it contains all the ordered sensors, accessories, and other components. Contact our support via e-mail at support@plux.info if there are any variations from your original order.
For regulatory information, please see the Regulatory Disclaimer at the end of this document.

PLUS – Wireless Biosignals, S.A.
Av. 5 de Outubro, n. 70 – 2.
1050-059 Lisbon, Portugal
plux@plux.info
http://biosignalsplux.com/

v.1.0
© 2020 PLUS
This information is provided “as is,” and we make no express or implied warranties whatsoever with respect to functionality, operability, use, fitness for a particular purpose, or infringement of rights. We expressly disclaim any liability whatsoever for any direct, indirect, consequential, incidental, or special damages, including, without limitation, lost revenues, lost profits, losses resulting from business interruption or loss of data, regardless of the form of action or legal theory under which the liability may be asserted, even if advised of the possibility of such damages.

Electrodermal Activity (EDA)
User Manual

General Information

1.1. General Description
The biosignalsplux EDA sensor is capable of accurately measuring the electrical properties of the skin which changes. These changes are caused by alterations in sweat secretion and sweat gland activity as a result of changing sympathetic nervous system activity. The low-noise signal conditioning and amplification circuit design provide optimal performance in the detection of even the most feeble electrodermal skin response events.
Together with the EDA Analysis for our OpenSignals (r)evolution software, one can easily record and extract meaningful event-specific temporal and spectral signal parameters for further analysis of the acquired sensor data.

Figure 1: biosignalsplux EDA sensor (standard version).

1.2. Typical Unfiltered Sensor Output
Figure 2 shows a typical unfiltered EDA sensor output acquired while seated and entering a more relaxed state as time progresses with gelled electrodes placed on the hand. The raw digital sensor values received from the biosignalsplux device ranged between 0 and 2 n -1 (n=sampling resolution) were converted into the original unit of measurement of this sensor (µ) using the transfer function found in section Transfer Function (Conversion Formula).

Figure 2: Typical unfiltered sensor output (while seated and entering a more relaxed state as time progresses).

1.3. Sensor Specifications

Bandwidth:
Input Bias Current:
Range:
Current:| 0-3Hz
±70pA
0-25µ
DC| > Consumption:
CMRR:
Measurement:| ±0.1mA
130dB
continuous
---|---|---|---

1.4. Features

Skin resistance measurement
High signal-to-noise ratio
Medical-grade raw data output| > Unobtrusive & lightweight sensor
Pre-conditioned analog output
Ready-to-use form factor
---|---

1.5. Applications

Life sciences studies
Sympathetic nervous system monitoring
Human-Computer Interaction
Affective computing
Psychophysiology| > Biomedical device prototyping
Arousal detection
Emotional cartography
Physiology studies
Relaxation biofeedback
---|---

1.6.Transfer Function (Conversion Formula)
The analog sensor signals acquired with biosignalsplux devices are converted into digital values ranging between 0 and 2 n
-1 (n=sampling resolution, usually 8-bit or 16-bit) and streamed in the raw digital format.
In most applications, the original physical unit of the acquired EDA signal is preferred or required. The raw digital sensor samples can be converted back into microelements (µ) using the following formulas:

Valid sensor range: [0µ, 25µ] with:

(µ)
()| EDA signal in microsiemens (µ)
EDA signal in siemens ()
Value samples from the sensor/channel (digital value)
Sampling resolution (default: 16-bit resolution (n=16), although 12-bit and 8-bit may also be found)
Operating voltage (3V when used with biosignalsplux)
---|---

1.7. Electrode Connections & Sleeve Color Meanings

Sleeve Color| Red|

Black

---|---|---
Electrode Cable| +| –

See section 2 Application Notes for more information on where to place the electrodes and to connect electrodes cables for EDA acquisitions.

1.8. Physical Characteristics

W1 x L1 x H1:
W3:
A1:
A3:| 1.6×2.2x.0.5cm
0.9cm
105.0±0.5cm
5.0±0.5cm| > W2 x L2 x H2:
L3:
A2:
D:| 1.5×1.75×0.55cm
0.5cm
5.0±0.5cm
0.4cm
---|---|---|---

Available sleeve colors: White, Black, Blue, Green, Red, Yellow, Gray, and Brown

Figure 3: Physical characteristics of the standard EDA sensor.

2. Application Notes
The biosignalsplux EDA sensor is designed to acquire the change of skin activity such as sweat with two measuring electrodes. One example is the placement of the electrodes on the anterior side of the hand on two adjacent fingers of interest (see Fig. 4). The electrodes are then connected to the sensor cable of the EDA sensor.
2.1. Electrode Placement/Sensor Placement

Figure 4: Example EDA placement I on the index and middle finger.

Possible electrode positions are listed in Table 1. The positive and the negative measuring electrodes can be positioned in either way.

Table 1: EDA electrode positioning.

| Positive Electrode (+) (red sleeve)| Negative Electrode (-) (black sleeve)
---|---|---
I| Finger location 1| Finger location 2
II| Finger location 2| Finger location 1

3. Using the Electrodermal Activity (EDA) Sensor with biosignalsplux & OpenSignals
3.1. Connecting the sensor to biosignalsplux Systems
3.1.1. biosignalsplux 4-Channel Hubs
The biosignalsplux EDA sensor is compatible with all 8 analog input channels of the 4-channel biosignalsplux hub, but incompatible with the reference/ground port. Connect the sensor to the analog input to use it with this device.

Figure 5: EDA compatible biosignalsplux channels (green checkmarks).

3.1.2. biosignalsplux 8-Channel Hubs
The biosignalsplux EDA sensor is compatible with all 8 analog input channels of the 8-channel biosignalsplux hub, but incompatible with the reference/ground and digital I/O ports. Connect the sensor to an analog input to use it with this device.

Figure 6:  EDA compatible biosignalsplux channels (green checkmarks).

3.1.3. biosignalsplux Solo & Single-Channel openBAN Devices
The biosignalsplux EDA sensor is compatible with the analog input channel of the biosignalsplux Solo (openBAN) device. Connect the sensor to the analog input channel to use it with this device.

Figure 7: Connect the EDA to the analog input channel of the biosignalsplux Solo (openBAN).

3.2. Configuring the Sensor in OpenSignals
3.2.1. OpenSignals (r)evolution (Windows, macOS, Linux)
Open the OpenSignals (r)evolution device manager to access and configure your biosignalsplux device.

Figure 8: Access the OpenSignals (r)evolution device manager.

Select the device you intend to use for acquisition by clicking on ENABLE button on the device panel in the OpenSignals device manager. The device is activated for acquisition if the ENABLE button is blue.

Figure 9: Enabling the device for acquisition.

Click on the biosignalsplux logo to access the available settings. Select the channel your sensor is connected to and select the EDA from the dropdown menu highlighted in the next screenshot.

Figure 10: Set the channel type of the channel you have your EDA sensor connected to, to EDA.

Activate the channel for acquisition by clicking on the circle next to the channel type (must be blue). If not done before, follow the instruction available in section 2 Application Notes to learn how to apply the sensors and 3.1 Connecting the sensor to biosignalsplux Systems to learn how to connect your device to your biosignalsplux device. Click on the record button in the OpenSignals main interface whenever you’re ready for your acquisition.

Figure 11: Start the acquisition whenever you’re ready.

4. Scientific Publications Using the SENS Sensor
The following scientific is only a small selection extracted from the list of available publications using biosignalsplux. Please visit the following website to access the entire up-to-date list: https://biosignalsplux.com/learn/publications.html
Publications
P. Morais, C. Quintão. “The Mindfulness Meditation Effect on Brain Electrical Activity: Stress
Assessment, Concentration State and Quality of Life.” Póster apresentado na 3ª Conferência de Eng. ª Biomédica na FCT/UNL., 2018.
A.B. Gago Veiga. “La predicción de la migraña. Análisis de la capacidad predictiva de los pacientes y de un nuevo sistema de monitorización multivariable.” , 2019.
S. Leite, et al. “Physiological arousal quantifying perception of safe and unsafe virtual environments by older and younger adults.” Sensors, vol. 19, no. 11, p. 2447, 2019.
D. Batista, et al. “Benchmarking of the BITalino biomedical toolkit against an established gold standard.” Healthcare technology letters, vol. 6, no. 2, pp. 32-36, 2019.
L. Müller, et al. “Körperliche und Emotionale Reaktionen in der Zusammenarbeit mit modernen
Robotern.” Technische Unterstützungssysteme, die die Menschen wirklich wollen, p. 507, 2018.
P. van Gent, et al. “Multi-level driver workload prediction using machine learning and off-the-shelf sensors.” Transportation research record, vol. 2672, no. 37, pp. 141-152, 2018.
P. Schmidt, et al. “Introducing weed, a multimodal dataset for wearable stress and affect detection.” Proceedings of the 20th ACM International Conference on Multimodal Interaction. 2018.
D.C. Rodrigues. Physiopad: development of a non-invasive game controller toolkit to study physiological responses for Game User Research. Diss. 2018.
M.T. Knierim, et al. “Exploring flow psychophysiology in knowledge work.” Information Systems and Neuroscience. Springer, Cham, pp. 239-249, 2019.
S.B. I Badia, et al. “Toward emotionally adaptive virtual reality for mental health applications.” IEEE Journal of biomedical and health informatics, vol. 23, no. 5, pp. 1877-1887, 2018.

Safety & Maintenance

5.1. Safety Instructions
Please read the following safety instructions before using your biosignalsplux system with the EDA  sensor to prevent any damages or problems with the user, test persons, and/or biosignalsplux devices. Violations of these instructions can lead to inferior signal quality and/or damages to the biosignalsplux system and user.

! The user should always keep the device and its accessories dry.
! The user must turn off the biosignalsplux device and contact Technical Support if the system or accessories reach uncomfortable temperatures.
! The user should not use the biosignalsplux device in noisy environments (environments with microwaves and other similar equipment). Doing so will lead to noise increase in the acquired signals and Bluetooth connectivity issues.
! The user must not use the device near the fire or in potentially explosive atmospheres, such as atmospheres with flammable gas.
! The user should only use the detection surfaces or other approved accessories purchased from
PLUX or by a PLUX agent.
! The user should inspect the sensors on a regular basis to ensure that they remain in good working order.
! The user should stop using the biosignalsplux device if experience any kind of discomfort or skin irritation.
! Do not use the system on persons with allergies to silver.
! The user should dispose of detection surfaces after using the biosignalsplux device. Detection sur- faces are single-user and disposable. Reusable electrodes should be reused by the same user.
Do not use reusable electrodes on several users.
! The user must not place the device in the microwave.
! The user must not insert objects into the holes of the device.
! The user should not open the biosignalsplux device or its accessories. The repair of the same should be only done by properly authorized PLUX personnel.
! The user should make sure the cables do not obstruct the passage of people.
! The user should use the sensor cables with extreme caution to avoid the risk of strangulation.
! The user should keep a safe distance between the biosignalsplux device and other devices to ensure their proper functioning.
! The user should only send the device to repair to qualified PLUX personnel.
! The user should not immerse the sensors or the biosignalsplux device, nor clean with liquid or abrasives.
! The user should handle the biosignalsplux device with caution and not expose the device or accessories to high accelerations and vibrations.
! biosignalsplux devices should not be used in patients with implanted electronic devices of any kind, including pace-makers, electronic infusion pumps, stimulators, defibrillators or similar.
! Do not apply electrodes over damaged or irritated skin.
! Do not use your device while charging its internal battery.
5.2. Transportation and Storage
Please follow these recommendations to ensure safe transportation and storage of your biosignalsplux equipment and sensors to prevent any damage to your system.
The biosignalsplux equipment and sensors should be stored in the original box in a dry place when those are not being used.

• Relative humidity: up to 95% with no condensation
• Ambient temperature: 10°C to 30°C
• Atmospheric pressure between 500hPa and 1060hPa

Whenever the equipment needs to be transported, it should be placed in the original box, since this was designed and tested to ensure the equipment and accessories are securely stored.
Take care while handling the transportation of the system and avoid dropping it, since the device is not shock-proof and should not be placed under stress or sudden acceleration.
5.3. Cleaning
Please follow these cleaning instructions to prevent any damage to the system or the user because of conducting cleaning methods that may cause any damage.

• The biosignalsplux and sensors should be visually checked before each use and cleaning process to ensure that no mechanical damage occurred.
• The biosignalsplux equipment and sensors (including the cables) should be cleaned with a slightly damp cloth or suitable absorbent paper, ensuring no liquid enters the equipment of sensors. Do not use detergent or any type of cleaning liquid as these may damage your equipment and/or sensor.
• Do not clean or re-use detection surfaces (electrodes). They are only suitable for single-use and should be disposed of after usage except indicated otherwise.

Ordering Guides, Regulatory & Legal Information

6.1. Ordering Guide
Please follow the following ordering guide when submitting orders of EDA sensors to orders@plux.info. If no specification is provided, the standard version of the sensor will be delivered.
Electrodermal Activity (EDA) Sensor

Description
Sympathetic nervous system measurement

Electrodes & Accessories
For a full list of available and compatible electrodes, please visit the biosignalsplux store.
6.2. Guarantee of Quality & Warranty
biosignalsplux sensors have three months quality guarantee from the date of purchase. PLUS  guarantees that the system, sensors, and accessories will be free from material or manufacturing defects for the mentioned time periods following the date of purchase.
If PLUX receives the notification of any such defects within the guarantee period, it will repair or substitute with the same unit\model, any products with proven defects at no cost to the client. During the repair period, PLUX promises to provide a temporary replacement under the same specification. Repairs will be carried out at PLUX’s premises after the equipment has been received.
6.3. Warranty Voidance
Usage of the device that is not in accordance with the handling instructions indicated in the manual, or use with accessories other than those manufactured by PLUX will invalidate the warranty of your devices. Be careful when connecting your biosignalsplux devices, sensors, and/or accessories to any third party device including the usage of the 3rd party connection components that are available for biosignalsplux systems as the usage of these components will void the electrical warranty of your biosignalsplux device and sensors and, if not indicated otherwise, the warranty of the 3rd party system you’re connecting to the device. Check the electrical specifications of both systems you want to connect to prevent any damage to the user(s) or the systems. In the case of warranty voidance, the same applies that we expressly disclaim any liability whatsoever for any direct, indirect, consequential, incidental, or special damages, including, without limitation, lost revenues, lost profits, losses resulting from business interruption or loss of data, regardless of the form of action or legal theory under which the liability may be asserted, even if advised of the possibility of such damages.
6.4. Contact & Support
Contact us if you are experiencing any problems that cannot be solved with the information given in the biosignalsplux documentation.
Please send us an e-mail with precise information about the error occurrence, device configuration, and, if possible, screenshots of the problem to support@plux.info.
6.5. Regulatory Disclaimer
biosignalsplux products are intended for use in life science education and research applications; they are not medical devices nor are they intended for medical diagnosis, cure, mitigation, treatment, or prevention of disease. we expressly disclaim any liability whatsoever for any direct, indirect, consequential, incidental or special damages, including, without limitation, lost revenues, lost profits, losses resulting from business interruption or loss of data, regardless of the form of action or legal theory under which the liability may be asserted, even if advised of the possibility of such damages.
6.6. Document Version Tracking

XX-

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PLUX Wireless Biosignals S.A.
email: plux@plux.info
web: http://www.plux.info
Headquarters
Zona Industrial das Corredouras, Lt. 14 – 1°
2630-369 Arruda dos Vinhos
Portugal
tel.: +351 263 978 572
fax: +351 263 978 902
Lisbon Office
Av. 5 de Outubro, n° 79 – 2°
1050-059 Lisboa
Portugal
tel.: +351 211 956 542
fax: +351 211 956 546

References

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