Re: Main hum noise

I once  
 
> From: [email protected]
> To: [email protected]
> Date: Wed, 23 Oct 2013 14:20:25 +0000
> Subject: Re: [Openeeg-list] Main hum noise
> 
> In reply to Alexandre regarding his "Main Hum Noise"...
> 
> Alexandre, if possible, I recommend that you try to use your OpenEEG system from a laptop computer.  Then, you can unplug the computer from the mains power.  If this makes the mains noise go away, then you know that your problem is indeed with regard to the power going to your primary computer.  In this case, you can work on isolating your OpenEEG from your computer, which is the path that you were asking about. 
> 
> If this is the case, you could consider a USB isolator.  I've used these products before with success:
> 
> http://www.bb-elec.com/Products/USB-Connectivity/USB-Isolators/USB-Isolators.aspx
> 
> Alternatively, if the laptop test (plugging and unplugging the power to the laptop) fails to make your noise go away, then you have a more difficult problem.  It is possible that the USB isolator will still help, but it is less likely to do so.  It is also possible that the Bluetooth link will help.  It is also possible (and very unlucky for you) that the mains hum is being radiated onto the human subject or onto the electrics.  This is more challenging to solve.
> 
> So, if you can borrow a laptop for a quick test, I would suggest that you try it.  If your noise goes away, it helps point to the problem.
> 
> Chip
> 
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> Date: Sun, 29 Sep 2013 18:45:03 +0200
> From: Alexandre Dubreucq <[email protected]>
> Subject: [Openeeg-list] Main hum noise
> To: "Discussion of EEG hardware, software, training protocols,	NFB
> 	theory - for developers and users."
> 	<[email protected]>
> Message-ID:
> 	<CAHmmOyNOo3DHZqpMtTDN=Rof==vgK9jDvNJ0unLp6tOpfH4KUg@mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Hi all,
> 
> I am trying to find a way to isolate my OpenEEG from the main hum because I get a real lot of noise.
> 
> I've got a question, in the case of a USB connexion to the PC : i understand that the opto-coupler isolate the DATA signal from the PC, to reduce hum or for device safety, maybe both ? But it doesn't isolate the VBUS/GND from the PC, correct ?
> 
> Then, my ideas are to :
> 
> (hard way)
> 1. use a bluetooth connection between device and PC, with external battery on device; (soft way) 2. use ONLY data from PC USB port, and provide the device with a external battery.
> 
> Did someone already tried one of these solutions ? Did it work ? What do you think ?
> 
> 
> Thanks a lot,
> Alexandre
> 
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