SHIELD-EKG-EMG

[bmidy]

I recently purchased a SHIELD-EKG-EMG.

I've some questions :
- is there any maximum length for the cable used from the Jack connector to the electrode ?
- what should be the value when nothing is connected ? I get a value around 500 (when read from the ADC from the OLIMEX 328
- I tried to connect some wire to a jack connector and put it directly to my arm, but when I contract I get many noise


thanks

[LubOlimex]

Hey,

The length and the quality of the cable can affect the quality of the readings, yes. We haven't tested maximum cable length. Note that also that different electrodes and different skin might affect the quality of the readings (using better electrodes and conductive gel is always recommended).

Typically, when no electrode is connected you should see a flat line in the visualization software.

A single wire is not sufficient. You need three wires to form a single channel - one wire for right electrode, one wire for left electrode, one wire for GND (electrical feedback). You can see how to connect the wires on page 16 of the user's manual here: https://www.olimex.com/Products/Duino/Shields/SHIELD-EKG-EMG/resources/SHIELD-EKG-EMG.pdf

Best regards,
Lub/OLIMEX

[bmidy]

Hi,

thanks for your answer.

When nothing is connected I get a almost "flat" line with a value around 500. is it ok?
I also ordered your official ECG Electrode and I get the same result.

I m using the OLIMEX 328 with he EKG Shield, and I followed all the instriuction.
I laso cut the wire on the R6 Pad.

What could be wrong ?

May be you could give me all the setting  I need to do , a small step-by-step HowTo. with all the jumper etc ...

Thanks

[LubOlimex]

Hey,

Yes, flat line in the middle between 0 and 1024 is normal and expected.

If you follow the user's manual - your setup should work properly. The step-by-step instructions in the manual were made with OLIMEXINO-328, SHIELD-EKG-EMG and the electrodes that we distribute (the same hardware that you have).

Best regards,
Lub/OLIMEX