Welcome, Guest

Author Topic: EKG/EMG too noisy  (Read 8624 times)

YotMagnet

  • Newbie
  • *
  • Posts: 2
  • Karma: +0/-0
EKG/EMG too noisy
« on: December 20, 2012, 02:32:22 PM »
Hello,

I've just received the Olimex EKG/EMG shield and the EKG/EMG-PA electrodes.

I've followed every steps in the manual but the result is far from expected.

Here :


Same bad results on brainbay...

Please help...
« Last Edit: December 20, 2012, 02:49:52 PM by YotMagnet »

Stan12

  • Newbie
  • *
  • Posts: 12
  • Karma: +5/-0
Re: EKG/EMG too noisy
« Reply #1 on: December 27, 2012, 09:11:13 PM »
What electrodes placement do you use?
I was using R+DLR on right forearm, L on left forearm. Metal plates are located on inner parts of forearms (less hair).
Keep hands close to each other, don't move  (and don't breathe :) )
The board is just a set of amplifiers, all noise is generated by electrodes/cabling system.
From your results it looks like DLR electrode is not connected.
Pls see mine recordings:
https://www.olimex.com/forum/index.php?topic=572.0

BTW, I tried snap connectors cable (see the picture in my post) and surprisingly, it works even worse.
May be, bad wires :(

« Last Edit: January 02, 2013, 09:35:38 PM by Stan12 »

YotMagnet

  • Newbie
  • *
  • Posts: 2
  • Karma: +0/-0
Re: EKG/EMG too noisy
« Reply #2 on: January 02, 2013, 11:05:56 AM »
Hi Stan,

First, happy new year.

Thanks for your answer. For placement, I put L on left forearm, R on right forearm and D on right leg. I'll try D on right forearm as you said and maybe switch to 3V to see the difference.
Also your other post is well detailed. I I'll keep you posted...

olimex

  • Administrator
  • Hero Member
  • *****
  • Posts: 815
  • Karma: +22/-3
Re: EKG/EMG too noisy
« Reply #3 on: January 04, 2013, 11:43:14 PM »
our cable is specially made, the casual anti-static bracelets with cable have 1M ohm resistor inside the snap cap and will not work

Stan12

  • Newbie
  • *
  • Posts: 12
  • Karma: +5/-0
Re: EKG/EMG too noisy
« Reply #4 on: January 04, 2013, 11:47:20 PM »
Hm.. has anybody mentioned  "the casual anti-static bracelets" here before? I don't quite get your comment.

Your cable could be good for resting EKG if only it has  leads long enough.


PS
Oh, are you referring to my remark
"I tried snap connectors cable (see the picture in my post) "?
Well, the cable I meant is shown in my post https://www.olimex.com/forum/index.php?topic=572.0 and IT IS NOT "casual anti-static". It is quite  usual ECG cable (although on a cheap side) designed to use snap connectors and disposable ECG electrodes. Disposable foam electrodes are most common in ECG(at least here in US).
« Last Edit: January 05, 2013, 12:00:54 AM by Stan12 »

olimex

  • Administrator
  • Hero Member
  • *****
  • Posts: 815
  • Karma: +22/-3
Re: EKG/EMG too noisy
« Reply #5 on: January 05, 2013, 12:25:38 AM »
yes stan12 your message for the snap on cable misleaded me to think that you try to use normal anti-static bracelet cable :)

MaxPaine

  • Newbie
  • *
  • Posts: 4
  • Karma: +0/-0
Re: EKG/EMG too noisy
« Reply #6 on: February 25, 2013, 09:19:35 AM »
Hi,
The screenshot of my setup looks exactly like the posted one.
Did anyone find a solution to this problem?

Regards,
Max

TecFun

  • Newbie
  • *
  • Posts: 1
  • Karma: +0/-0
Re: EKG/EMG too noisy
« Reply #7 on: March 09, 2013, 12:15:45 AM »
Hi there .. i also experimented with the Shield the Video: http://www.youtube.com/watch?v=uuGDnuqZqu8 is from me f.e.

I noticed that on the Screenshots theres a stable 50Hz Noise =)
So what power-source you are using to Power the Shield?! .. if its not a power-converter ... you should check if some powerline is producing this effect ... atleast a 50Hz signal is mostly produced by a bad power-supply ...