Hi Leonid, Here at Shimmer Research we are currently in the process of producing EMG, ECG and GSR User guides to allow users to overcame the initial difficulties of using a sensor that they may not be familiar with. The User Guides include some basic information on verifying that your that hardware is operating as expected and indentifying any potential sources of signal noise.
The EMG User Guide is currently available here on our website http://www.shimmer-research.com/wp-content/uploads/2012/05/Shimmer-EMG-User- Guide.pdf The ECG User Guide is currently available by request ([email protected]) and will be on our website shortly and the GSR User Guide should be available in the coming weeks. Best regards, Karol From: [email protected] [mailto:[email protected]] On Behalf Of Leonid Ivonin Sent: 22 May 2012 17:36 To: Matthias Van Gysel Cc: [email protected]; H.M. Albert Chang Subject: Re: [Shimmer-users] Strange data-peaks Hi Matthias, In our lab we have recently experienced a problem that is very similar to the one you described. We recorded ECG signal with Shimmer sensor and the C# application provided by Shimmer. The data collected with this sensor for 10 our of 36 participants was corrupted by a strong noise with high amplitude. We are pretty sure that this noise was not caused by external factors, because during the measurement our participants were instructed to sit still and also we made sure that the connection of electrodes to their skin was good. Moreover we were not able to find any pattern in this problem, it happened randomly. We assume that at some point of measurement something went wrong in the sensor, but we have no idea what caused it. I have attached a sample screenshot. On the left side of the picture you can see normal ECG signal, then at some point of time it just becomes a high amplitude noise. Filters do not help to eliminate this noise. That is our experience :) Regards, Leonid On Tue, May 22, 2012 at 6:09 PM, Matthias Van Gysel <[email protected]> wrote: Hi, I'm currently working on a project that streams data over a Bluetooth connection from a Shimmer2r sensor to a C# application. I record this data, but when I open the recorded data-file, lots of the data seems to be corrupted or something like that. Data peaks that go as high as 60, when actually the data is normalised to change its value between -1.5 and 1.5. I have tried to test whether it is the sensor, the connection or the application that is causing these errors to the data but I can't work it out. Does anyone ever had the same type of problems? Or knows what this data means and where it comes from? I have talked about this to one of my supervisors and he said that it might be the AD-conversion on the Shimmer device itself that is still changing values when the data is already being transmitted to the application. I don't have a single clue anymore so I really hope someone can help me out here. I inserted a screenshot of the corrupted data into this mail. The screenshot shows the corrupted data and what it normally should be. Matthias Van Gysel _______________________________________________ Shimmer-users mailing list [email protected] https://lists.eecs.harvard.edu/mailman/listinfo/shimmer-users
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