what do i need to measure muscle activity

[cees10]

Can some body explain what i need to  measure muscle activity?

i have a 6210  

so  i have to buy emg sensors  but   ,do i need amplifier for this signal ?   can i use amplifier that i use for strain gauge's?

what elso on hardware side do i need?

[Steve.J]

You need a biopotential amplifier.  Please refer to this document on our Biomedical User Group website.

[cees10]

Thanks

is this also true for a 6216? 

[cees10]

the 6216 because it has bank isolation    not enough?

[Steve.J]

The amplifier is not needed just for safety - it is also needed to provide the proper signal conditioning before the DAQ device.  You need an AC-coupled, balanced differential input with a high CMRR to block the large DC offsets and reject the high common mode noise (from 50/60Hz line frequency) that are inherent in these kinds of recordings.  NI DAQ devices do not have these kinds of inputs/features.  However, they are great for digitizing the analog outputs from a good biopotential amplifier.

Steve

[cees10]

Hi steve

The problem is there is no ac

Since there is only a laptop

We also do not have any other attachement to a machine or other wise

its for measurement  human emg on a bike

So evrything low voltage

So no noise or strange other things  ,thats why i ask my selve why can i not use the aplifier of strain gauge

[Steve.J]

You can buy low-cost bioamplifiers that have battery power (these are also safer to use) such as this: http://www.grasstechnologies.com/products/amplifiers/p55.html

The AC line noise (50/60Hz) is not just from AC powered instruments - it is also radiated EMI that comes from lighting, wall wiring, etc. - it is very hard to avoid.  A good bioamplifier will reject this noise since it is common-mode (appears in both electrodes more or less equally) and only the difference signal is amplified and passed to the DAQ device for digitizing.

[cees10]

Ok thanks steve,   i understand now the worry  this also means if your in the field (outside you hardly would expect any noise )

Planned a hospital test on my selve.

I will look what the differnace gone be .

I emailed them (grasstechnologies),  to order it now          hope they want to sell it !

Anyway thanks   meaby talk to you within 2 weeks in (austin) 

Message Edited by cees10 on 12-14-2009 02:32 PM