This article provides everything you need to know to start recording data with your BITalino Electrodermal Activity (EDA) sensor, sold in two different versions: UC-E6 and assembled (Fig.1).
Fig. 1: BITalino EDA sensor, UC-E6 (left) and assembled (right)versions.
Connecting Your Sensor
If you are getting started with the BITalino EDA sensor, UC -E6 version, you need to connect your sensor to one of the analog channels (An, where n ranges from 1 to 6) available in the BITalino Core (MCU+BLE/ BT +Power) unit as shown in Fig.2. This connection is made trough a 2-lead electrode cable to the sensor and then you can use a sensor cable to connect the sensor to the board as shown in the Fig. 2.
Fig. 2: How EDA UC-E6 sensor must be connected to the BITalino Core Unit.
Alternatively, you can connect your EDA UC -E6 sensor to an Arduino device. For this set-up we advise you to read this support article.
When you start with the BITalino EDA sensor, assembled version, your sensor is already connected to the 2-lead electrode cable in a 3D printed housing. This sensor version is usually combined with the Assembled BITalino Core BLE/BT or used in the PsychoBIT Application Kit, designed to explore psychophysiology.
If this is your use case, you can connect your sensor to one of the available analog (An, where n ranges from 1 to 6) channels highlighted in the back of the device (Fig. 3).
Fig. 3: Representation of the BITalino assembled version of the EDA sensor and core unit.
Placing Your Electrodes
The BITalino EDA sensor is designed to acquire the change of skin activity such as sweat with two measuring electrodes. For ensuring the best conditions for high-quality signal acquisitions we recommend the following steps for your electrode placement:
- Skin Preparation: there is normally no need for pretreatment of the skin where active recording will take place, unless the skin is dirty. If that’s the case you can clean it lukewarm water prior to the electrode attachment. Washing with soap is not recommended because it may cause swelling of the epidermis, impacting this way the results. We also recommend some precaution in using alcohol-based solutions to clean the skin once the skin salt concentration may change. Use it only in case of the skin contain excessive oil (Source: Society for Psychophysiological Research Ad Hoc Committee on Electrodermal Measures, et al. “Publication recommendations for electrodermal measurements.” Psychophysiology 49.8 (2012): 1017-1034)
- Electrodes: Ensure that you are using a new pair of electrodes when using disposable electrodes or to properly clean your reusable electrodes before use
- Measuring Electrodes Placement: Place the electrodes along on the fingers or alternatively in the hand palm, e.g. on the abductor pollicis brevis.
As mentioned above, you can make the electrodes placement on the anterior side of the hand or on two adjacent hand fingers of interest (see Fig. 4).
Fig. 4: EDA Electrode position on the hand fingers
The EDA sensor’s electrode cables come with two colored sleeves to mark the positive (red sleeve) and the negative (black sleeve) (Fig. 2 and 3). The positive and the negative measuring electrodes can be positioned in either way on the fingers belly, e.g. middle phalanx.
To learn more about the EDA electrode positioning and signal acquisition you can consult the following documentation:
Setting Up OpenSignals
This setup is compatible with our OpenSignals software which you can download for free.
To setup your device and sensor, enter the OpenSignals device manager by clicking on the icon highlighted below.
Click on the device panel of your device (make sure your device is turned on) and click on the READ SENSORS icon to setup your device. After a few seconds, your sensor should be listed in the device panel with the channel port matching the port to which you connected your sensor to the biosignalsplux hub.
Activate your device for acquisition by ensure that the ENABLED button is blue (click on it if it is in grey).
To learn more visit our page “How to set up my BITalino in OpenSignals device manager?“
Frequently Asked Questions (FAQs)
Why am I getting a bad EDA signal ?
When using the BITalino EDA sensor in combination with other ExG sensors it is common to observe the interference of the reference electrodes with the EDA measurements. If you’re noticing a weird behavior in the EDA signal, you can find more detailed information in the following article:
What are the electrodes can I use the sensor with?
If you are inexperienced with signal acquisitions, we recommend starting off with the disposable electrodes due to their easy-of-use and greater signal quality. You can find more detailed information in the following article:
What signal processing software do you provide for the EDA sensor?
We have in our product offer one signal processing add-on for our OpenSignals software.
If you are looking for an open-source software you can explore more on our article the following support article: