No issues have been reported to Shimmer to the best of my knowledge (and I would see them). Someone from Shimmer support may contact you on the firmware side. In the meantime, can you provide background on your sample rate, electrode type/location, etc.? Is there a chance that you are sampling too fast (eg. >50Hz)? I'm not sure if the auto-range function has been tested at fast sample rates.
Thanks, Ben On Wed, Sep 5, 2012 at 5:55 PM, Fola Alamudun <[email protected]> wrote: > Here is a zoomed figure. > I suspected just what you said. I have looked over the code I am using and I > suspect that the autorange function may need tweaking. > Your suggestion to shift the range upwards away from the trouble range and > maintain a constant range versus autorange may be one good solution. > However, i'd prefer to find a solution where i can still use autorange. Data > collection will be in excess of 6 hours a day and so i am certain a singular > range value will not work for our experiments. > > The autorange function i am using is the shimmer provided Gsr.controlRange > function. Is there a known issue with this? if so is there a workaround that > has been tested? > > Thanks for your prompt response and i look forward to your reply. > > > "Nothing will benefit human health and increase chances for survival of life > on Earth as much as the evolution to a vegetarian diet." ~ Albert Einstein > (1879 - 1955). > > Fola Alamudun > Computer Engineering > Texas A&M University > mobile: 469-995-4088 | email: [email protected] > > > On Wed, Sep 5, 2012 at 4:43 PM, Benjamin Kuris <[email protected]> wrote: >> >> Fola, >> If you look at the data, the artifact always occurs at the same value >> (in the y-axis). I suspect that it is an artifact from the >> auto-ranging function. You are having the issue at ~1.6uS, or 625k. >> There is a autorange switch at 680k (1470uS), which I think is very >> suspicious. You could try collecting data without auto-ranging and >> compare the results -- for example, if you select range2, accuracy >> will suffer <1470 but you should have the results you want for peaks >> of GSR activity. >> >> Alternatively you could try skin preparation to shift the GSR curve >> upwards away from the range transition or changing the time constants >> in the code for auto-ranging. >> >> I would also point you to the GSR User Guide Rev 1.0 on the Shimmer >> website-- what sample rate are you using? Can you provide a >> sample-level zoom in to one of the saturation periods? >> >> -Ben >> >> >> On Wed, Sep 5, 2012 at 5:21 PM, Fola Alamudun <[email protected]> >> wrote: >> > I am including images of what the data looks like over a period of about >> > 6 >> > hours of data collection. >> > Does anyone have any advice on how to fix this issue? I have read that >> > this >> > may have to do with pressure on the gsr node which may cause flat-lining >> > as >> > we are seeing in our data. >> > >> > >> > "Nothing will benefit human health and increase chances for survival of >> > life >> > on Earth as much as the evolution to a vegetarian diet." ~ Albert >> > Einstein >> > (1879 - 1955). >> > >> > Fola Alamudun >> > Computer Engineering >> > Texas A&M University >> > mobile: 469-995-4088 | email: [email protected] >> > >> > >> > On Tue, Sep 4, 2012 at 7:32 PM, Fola Alamudun <[email protected]> >> > wrote: >> >> >> >> Hello all, >> >> >> >> I am having some issues with the shimmer gsr unit. When we configure >> >> this >> >> unit to collect data using the auto range function, we notice that the >> >> resistance values saturate about half way / three quarter way through >> >> data >> >> collection. >> >> I noticed someone else had experienced this but saw no response to the >> >> question and so i am reposting with the hopes to find a solution to >> >> this >> >> soonest. >> >> We are using shimmer gsr and it has an orange padding between the gsr >> >> unit >> >> node and the main board (this, i read, was supposed to reduce the >> >> possibility of the sensor saturating due to pressure). >> >> Thanks in advance for any help i receive. >> >> >> >> >> >> "Nothing will benefit human health and increase chances for survival of >> >> life on Earth as much as the evolution to a vegetarian diet." ~ Albert >> >> Einstein (1879 - 1955). >> >> >> >> Fola Alamudun >> >> Computer Engineering >> >> Texas A&M University >> >> mobile: 469-995-4088 | email: [email protected] >> > >> > >> > >> > _______________________________________________ >> > Shimmer-users mailing list >> > [email protected] >> > https://lists.eecs.harvard.edu/mailman/listinfo/shimmer-users >> > > > _______________________________________________ Shimmer-users mailing list [email protected] https://lists.eecs.harvard.edu/mailman/listinfo/shimmer-users
