Measuring multiple resistances: independently and wide range

Hello Arduino Community!

For a university project, I am working on an interactive dance costume. We are using 6 conductive pieces of self knitted sensors and measure the values with parallel ohm meters. We got it working once in the beginning as we measured the max and low resistance the fabrics gave us and used the average as a resistor value. We were able to improve the results a little by adding a capacitor behind the resistor. However, it seems that the resistance of these fabrics differs quite a lot (humidity, sweat of dancers maybe corrosion?). I am absolutely unsure how we could improve the range that is measured. Are there any commercially available ohm meters that can be used with Arduino? Or how do I know which resistance and capacitance value could work robustly? I have almost no knowledge in electronic circuits as I am a Human Computer Interaction student: any help would be appreciated!

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The capacitance can remove some noise. With a little calculation and some guessing a value can be determined. I have read most pages about testing and making the sensors. I think that the value will not be the same when released, and that the value changes with many things. Since the human ear can hear a small change in frequency, you need something better.

The best would be a string (not conductive) with a sensor at the end that measures the pulling force with strain gauges. That would be so accurate that it can be used to measure a weight at the end of the string. I don't know if such thing exist.

A flexible fabric that changes resistance and is also accurate ? I think that is hard to find, perhaps even impossible. I have done some tests with conductive rubber, but it was too inaccurate.

Here are more materials : http://www.kobakant.at/DIY/?p=913

Adafruit has this : https://www.adafruit.com/product/519 Did you test that ?

For clothing and electronics, Adafruit has the best knowledge about that. I'm sure they will be glad to help if we don't know a better solution.

Thanks! we also worked with resistive fabrics but it wore out quite quickly which is why we integrated simply multiple layers of conductive yarn and use rubber band to return to the original position.

So from software and hardware, there is not much improvement on the accuracy of the sensors that works almost in real-time? I do an FFT transform on the data as I thought it might help to distinguish different movement patterns but I do not know which window size to use or which frequency responses would be meaningful.

Regards,
Hauke

I don't know how a FFT would help. If the sensor data is not very accurate, then it can not be made more accurate.

The rubber cord from Adafruit is also used by others. It might be worth to try it. I have not tried it myself.

Are you wanting to principally measure shape change or force? They are related, but some techiques just measure position/orientation directly, as used in motion capture suits with IR cameras (I suppose multiple IMU sensors could also be used directly in the costume.

One problem you will have with conductive sensors is the need to insulate them (sweat is too good a conductor as I think you are discovering).