Olimex Support Forum

Others => Biofeedback - EEG, ECG, EKG => Topic started by: Janne1002 on November 28, 2020, 09:44:17 pm

Title: No data from SHIELD-EKG-EMG
Post by: Janne1002 on November 28, 2020, 09:44:17 pm
I have installed the Olimexino-328 and SHIELD-EKG-EMG by carefully following all instructions in the manual on the Olimex webpages. When I start Electric Guru I get a noisy zero-signal with low amplitude. If I mess with the electrodes I can generate big amplitude noise but once electrodes are stationary, I always get this same zero-signal. I can get some low amplitude oscillations if I only attach one electrode to my arm but once all electrodes are attached the signal is always the same. I can even unplug the electrodes connector to the shield and the signal stays the same. I bought two sets of electrodes and that doesn't change things and I have made Electric Guru installations on a Win10 and a Win7 machines, with no change. Finally, I have switched around the 5-3.3V switch and of course that didn't help. I have posted a trace on my dropbox: https://www.dropbox.com/s/eqrv4iv82a6rrtw/Trace%20typical1%20ElectricGuru.jpg?dl=0
Can somebody please help me get the system going ;D
Title: Re: No data from SHIELD-EKG-EMG
Post by: LubOlimex on November 30, 2020, 11:36:28 am
What electrodes are you using? How do you place them?
Title: Re: No data from SHIELD-EKG-EMG
Post by: Janne1002 on December 05, 2020, 08:09:55 pm
I'm using the standard shield-ekg-emg-pa. It is light blue and the product number ends with 2359. I bought two sets. It doesn't really matter how I place them, the signal is the same. I have tried to put the L/R below the elbows and on wrists and the D on my ankle and leg and wrist. I have switched them around in various permutations. And of course tried it all with both both bracelets.
Title: Re: No data from SHIELD-EKG-EMG
Post by: Janne1002 on January 08, 2021, 12:16:39 pm
Finally I had to order a new SHIELD-EKG-EMG board to confirm my suspicion that my original was somehow damaged. The Olimex-328 was sending data to the serial port, so that's why I suspected the SHIELD. And, yes, as soon as I hooked up the new SHIELD I got good data to elec guru. Now I use Matlab to read the serial port an play with the data. I want to explore the heart coherence topic.
Title: Re: No data from SHIELD-EKG-EMG
Post by: LubOlimex on January 08, 2021, 04:56:55 pm
Glad you manage to find the root of the issue. Interesting how the shield got damaged. Where did you got the original shield from? Was it directly from us?