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Topic: Clipping of signal and EEG distortions (Read 508 times) previous topic - next topic


Hi, I start apologizing because I will give any of you that want to help me an hard time.

I am using an EEG device and an alternate current stimulator (tACS).
I have a normal EEG electrode that it is attached both to the EEG amplifier, and at the stimulator, to alternate recording and stimulation, without changing cables

The problem is that when I stimulate the current will flow from the stimulator to the channel and then directly to the amplifier. This will cause two problems:

The stimulation will not flow out to the channel and will not pass to the brain, making all the story pointless.

The amplifier handles brain signals to the range of 1 - 100 milliVolts, while the stimulator stimulates up to 1 milliAmpere. So the impulse from the stimulator coming back will break the amplifier.

My question is:
Can I use arduino to selectively put a resistance between the electrode and the amplifier when the signal is too high. So when I am stimulating the current flows from the stimulator to the channel to the reference of the stimulator (on the other side of the head), and when I am not stimulating the signal is not distorted by the arduino?

I am sorry, I am pretty ignorant about arduino and even the simplest physic behind what I want to do. But knowing that it would be possible to realize this with arduino will push me and my group to put the necessary effort in it.

I hope someone there can help me and I did not broke any rule of the community.. I never read the licence agreements

Thanks, Valerio

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