View Full Version : Responses to "Using Force Sensing Resistors to detect coarseactivity"

Maja Vukovic
05-20-2003, 02:09 AM
As I have received several requests for copies of the responses, I am posting a summary of replies from all the contributors to my question(s).
Thanks everyone for their help!

Maja Vukovic
Computer Laboratory
University of Cambridge
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Original message:
I am a PhD student in Computer Science looking into sensing the human activity in order to make computing applications more 'aware' of users, their state and environment.

In particular I would like to infer the coarse activity of the human being (e.g. walking, running, standing) using wearable insole FSRs.

I've read about Force Sensing Resistors on this mailing list and on the Internet, but still have some questions.
Not having any biomechanics background I'd like to find out:

a) does it make sense to pursue this direction of using an insole force sensing resistor to infer just the coarse activity of the human (I am not interested in the gait analysis etc.).
b) does anyone have any experience with building such a sensor (i.e. if I use the FSRs from Interlink what would be the best interface?) - any tips & pointers would be appreciated
c) are there any existing databases with FSRs and where could I find them ?

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Summary of responses:

a) I have received about 15 replies. Most of them pointed that for inference of activity accelerometers and/or gyroscope (strapped to ankle or thigh) are a lot simpler to use and more reliable than FSR-based insoles.
- FSRs are known for problems with their non-linearity and accuracy (they are alright for gross measurements )
- building hardware of that type is always difficult and time consuming (for beginners especially)
- could be difficult to make a reliable measurement system (as humidity and raised temperature insole affect readouts, etc).

b) Information how to build an in-sole force sensing and a list of already existing 'products'/prototypes as such:

Hausdorff JM, Ladin Z, Wei JY. Footswitch system for measurement of the temporal parameters of gait. J Biomech. 1995;28:347-351
Contact: Microsports in Portsmouth, Dr. Mike Smithard

Suggested interface (for Interlink FSRs): INTAB (sweden) pc logger 3100

c) Databases with FSRs/activity information

Physiolog - a log with motion activity (over a period of one month)

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