Use of electrodes

Manuals & Documentation for BITalino
supercourge
Posts: 6
Joined: Tue Mar 25, 2014 2:12 am

Use of electrodes

Postby supercourge » Tue Mar 25, 2014 2:21 am

Hello,

I was wondering if you could provide us with information (or step by step tutorial) concerning the placement/use/maintenance/... of the electrodes (for ECG, EMG and EDA).
I'd like to use Bitalino for a research project, but I never used any physiological sensors nor electrodes.

Thanks you in advance.

cazevedo
Posts: 18
Joined: Tue Feb 25, 2014 2:17 pm

Re: Use of electrodes

Postby cazevedo » Tue Mar 25, 2014 2:32 pm

EDA
The commonly used sensor placement positions are annotated in the image. The most frequently found are the AB (index - middle finger), AC (index - 3rd finger), and DE (thenar eminence).

EDA Placement.png
EDA Placement
EDA Placement.png (160.4 KiB) Viewed 11314 times


EMG
The EMG electrodes should be placed alongside the muscular fibers with a 2 cm spacing between them (G and H). They should be preferentially placed on the belly of the muscle. This corresponds to the more central area of the muscular fibres and may be found by performing a muscular contraction. The third electrode (F) is the referential and should be placed in an area of low muscular activity, usually a bony area. Please bear in mind that this image is only an example and so as long as these rules are followed the sensor may be placed in any muscle.

EMG Placement.png
EMG Placement
EMG Placement.png (192.38 KiB) Viewed 11314 times


Furthermore, if the application consists only in detecting a muscular activation the placement of the three electrodes in line should be sufficient. You may see some examples of this last option in here:
https://www.how.do/guide/bitalino-train-that-tempo
https://www.youtube.com/watch?v=ectJrNScZpw
https://www.youtube.com/watch?v=GHrtN-rZHiE
https://www.youtube.com/watch?v=co_f_aaHEEA

ECG
For ECG we suggest a triangular electrode placement such as the image bellow illustrates where the ground should be the electrode in the middle (I). The order of the other two electrodes is irrelevant (J and K).

ECG Placement Triangle.png
ECG Placement Triangle
ECG Placement Triangle.png (192.18 KiB) Viewed 11314 times


Regarding the use of the electrodes, they are disposable and may be used only once. The skin should be cleaned with alcohol before the placement and also should be safeguarded that the skin is dry. It is also good to ensure that there is an area without any hairiness.

Best regards,
Carlos
Last edited by cazevedo on Tue Mar 25, 2014 5:52 pm, edited 1 time in total.

cazevedo
Posts: 18
Joined: Tue Feb 25, 2014 2:17 pm

Re: Use of electrodes

Postby cazevedo » Tue Mar 25, 2014 5:51 pm

Notice that for ECG there are also other possible configurations such as the Einthoven triangle or even a option with the electrodes placed on two fingers. Regarding the Einthoven triangle the ground electrode corresponds to the letter M, the cathode to the letter N and the anode to the letter L. Regarding the option on two fingers it should be used the two lead snaps because the ground electrode does not need to be connected. The order of placement of the other two electrodes (anode and cathode) is indifferent.

The images bellow illustrate this two options respectively.

ECG Placement Einthoven.png
ECG Placement Einthoven
ECG Placement Einthoven.png (191.33 KiB) Viewed 11314 times


ECG Placement Fingers.png
ECG Placement Fingers
ECG Placement Fingers.png (250.33 KiB) Viewed 11314 times


Best regards,
Carlos

supercourge
Posts: 6
Joined: Tue Mar 25, 2014 2:12 am

Re: Use of electrodes

Postby supercourge » Wed Mar 26, 2014 3:05 am

Thanks you a lot for your answer.
I have a last question: The ground electrode is a particular electrode? Or it can be any of the three electrodes?

BITalino
Site Admin
Posts: 537
Joined: Tue Aug 27, 2013 3:47 pm

Re: Use of electrodes

Postby BITalino » Wed Mar 26, 2014 7:44 am

supercourge wrote:Thanks you a lot for your answer.
I have a last question: The ground electrode is a particular electrode? Or it can be any of the three electrodes?


Hi,

The ground electrode is the center cable on your 3-lead accessory, which should correspond to the pin labelled REF on the back of your board.

Best regards,
Hugo Silva

Wagi
Posts: 4
Joined: Thu Mar 27, 2014 2:40 pm

Re: Use of electrodes

Postby Wagi » Fri Mar 28, 2014 11:31 am

What's wrong?

I tried all electrod positions posted in this forum (ECG).
I opend OpenSignal and made this configuration:
Image

BUT I don't see a typical ECG wave form.
AND whenever I take bitalino in my hands there are big waves..

I don't understand how I should use it in mobile situations!

Can somebody help me?

I connected it the 3-lead on ECG analog??
(i still don't understand why it is analog and how I can work with digital)

Sorry for these questions but I'm still a noob!

BITalino
Site Admin
Posts: 537
Joined: Tue Aug 27, 2013 3:47 pm

Re: Use of electrodes

Postby BITalino » Sat Mar 29, 2014 12:00 am

Hi,

Please confirm if the labels on the OpenSignals software configuration match the channel mapping on your BITalino hardware. We've changed the analog input mappings on a recent version, reason for which the ECG may not be the channels labelled as ECG in OpenSignals (note that you can change the labels).

From top to bottom, the text boxes on the software settings correspond to channels A1, A2, ..., A6. On the back of you BITalino Board, the pins on the sensors should have labels on them, and one of the pins should have an AX label, X being the channel number... check what the number on the ECG is.

In the latest model (Early-2014), the ECG should be A3, hence you should check the third box counting from the top. Another alternative is for you to check all channels and see where the ECG pops up. Feel free to contact us for any further question.

Best regards,
The BITalino Team

Wagi
Posts: 4
Joined: Thu Mar 27, 2014 2:40 pm

Re: Use of electrodes

Postby Wagi » Mon Mar 31, 2014 9:39 am

THANK YOU!!!
That's an important Information!

AuthorOfTheSurf
Posts: 5
Joined: Tue Jan 27, 2015 4:26 pm

Re: Use of electrodes

Postby AuthorOfTheSurf » Thu May 07, 2015 5:04 pm

I wanted to mention that the EMG diagram helped me out tremendously. I had been using the 2-electrode attachment and the data wasn't that pretty, I had noise cancellation listed as a later task in my project... After switching to the 3-electrode and actually using the ground, the data is awesome! I had no idea why it was a different color, or why the wires were so much longer than the 2. It's a nice line that looks as I would expect it to w.r.t. how much I was activating my muscles.

Somehow I didn't come across this info sooner. I had just purchased 1, 2, and 3 electrode attachments just for variety, and to use less electrodes for testing. I had no idea that using the 3-electrode for EMG would make all the difference!

BITalino
Site Admin
Posts: 537
Joined: Tue Aug 27, 2013 3:47 pm

Re: Use of electrodes

Postby BITalino » Thu May 07, 2015 9:29 pm

Hi there,

Great to hear that everything turned out OK. We've recently released documentation for each of the sensors:
http://bitalino.com/index.php/learn/documentation

Each sensor data sheet includes useful information such as electrode cable usage recommendations and example placement:
http://bitalino.com/datasheets/EMG_Sensor_Datasheet.pdf

Best regards,
The BITalino Team


Return to “Manuals & Documentation”




cron