EMG SENSOR ACQUISITION

Connection, ECG, EMG, EDA, etc.
Velu
Posts: 6
Joined: Fri Nov 03, 2017 12:26 pm

EMG SENSOR ACQUISITION

Postby Velu » Sat Nov 18, 2017 9:47 pm

Hello Team,

I have been trying to do EMG sensor acquisition with the STM32F4 kit. I've tested the ADC functionality of my code using a potentiometer and it does work well. However, when I am connecting the sensors analog output to the GPIO pin of the STM kit, I just see the random ADC values.

I've used the REF voltage as VCC/2 through the PWR block. I've placed the electrodes (3-lead) as suggested in http://bitalino.com/datasheets/EMG_Sensor_Datasheet.pdf

Please find the schema below that I've used. (VCC = 3.3V)
https://www.dropbox.com/s/a2egp9lhx1wvp ... a.PNG?dl=0

Any help or suggestion is greatly appreciated. Thanks.

Yours sincerely,
Velu

p.s. I am using the BITalino Freestyle BT Kit.

BITalino
Site Admin
Posts: 567
Joined: Tue Aug 27, 2013 3:47 pm

Re: EMG SENSOR ACQUISITION

Postby BITalino » Sun Nov 19, 2017 12:02 am

Hi Velu,

First of all we'd like to thank you for your contact and preference for BITalino.

Can you send us a photo of your setup and some sample data as well?

From your provided resources, everything seems to be connected correctly.

Best regards,
The BITalino Team

Velu
Posts: 6
Joined: Fri Nov 03, 2017 12:26 pm

Re: EMG SENSOR ACQUISITION

Postby Velu » Mon Nov 20, 2017 2:59 pm

Hi Team,

Thanks for the response.

Please find the picture of the setup and the sampled data here:
https://www.dropbox.com/sh/ijq0k0kewjji ... Z1iza?dl=0

I've done the conversion of ADC output value to the voltage using this link: viewtopic.php?t=128

I'm an absolute beginner with the sensor acquisition, so any kind of comments/suggestions are welcome. :)

Best regards,
Velu

BITalino
Site Admin
Posts: 567
Joined: Tue Aug 27, 2013 3:47 pm

Re: EMG SENSOR ACQUISITION

Postby BITalino » Mon Nov 20, 2017 10:17 pm

Hi Velu,

Is the STM board powered by the battery ou from the USB? Please try your setup without using the BITalino PWR block, and creating the REF line using a voltage divider and let us know how it works out. Also, if you have the chance, test a similar setup with the STM board powered from a power bank (e.g.).

Best regards,
The BITalino Team

Velu
Posts: 6
Joined: Fri Nov 03, 2017 12:26 pm

Re: EMG SENSOR ACQUISITION

Postby Velu » Wed Nov 22, 2017 5:24 pm

Dear Team,

Thanks for the response.

Yes, the STM is connected via USB and I've read somewhere in the forum, the laptop is preferred to be in the Autonomous mode (Not in the charging mode).

Today, I've managed to see some good results (I believe). I am sharing them with you for your reference here: https://www.dropbox.com/sh/t01ru4nho3eo ... oD-oa?dl=0

Kindly give me your feedback.

Regards,
Velu
Last edited by Velu on Wed Nov 22, 2017 8:00 pm, edited 1 time in total.

BITalino
Site Admin
Posts: 567
Joined: Tue Aug 27, 2013 3:47 pm

Re: EMG SENSOR ACQUISITION

Postby BITalino » Wed Nov 22, 2017 6:42 pm

Hi Velu,

Great news! These results are indeed compatible with what would be expected from a normal EMG signal.

Thanks for sharing this experience with us. In case we can be of any further assistance, let us know.

Best regards,
The BITalino Team


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