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My question is mainly the following:

Is there a force-sensitive resistor that can handle pressure (like 50kg weight) constantly on it? While not having its response curve altered because of this?

Well, the backstory of the problem is that I have been using normal force sensitive resistors like these, and the problem they have is that if you apply the pressure on them constantly, their response curve will flatten out and you will no longer be able to detect minute changes in the pressure. This limitation is also discussed in their datasheet. So my question is: What alternatives do you think I have, to circumvent this issue?

What I am trying to accomplish:

I want to have a force-sensitive resistor, similar to the one I mentioned before. The only problem with the one above, is that if I constantly apply pressure on it (or apply pressure on it over long periods of time), the resistance curve becomes almost a flat line and I will no longer be able to use it. I want something that presents the same behavior as the force sensitive resistor above, however, is more durable when a DC force is constantly being applied on it.

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  • \$\begingroup\$ You need to describe what you're trying to accomplish better. \$\endgroup\$
    – Scott Seidman
    Dec 27, 2019 at 2:30
  • \$\begingroup\$ Thank you @ScottSeidman, added more information \$\endgroup\$
    – gloomysunday
    Dec 27, 2019 at 2:33
  • \$\begingroup\$ You just repeated yourself. Can you describe more about the situation? What exactly are you trying to detect? What sort of sensitivity do you need? Are you measuring over hours, months, years,....? \$\endgroup\$
    – Scott Seidman
    Dec 27, 2019 at 2:35
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    \$\begingroup\$ @gloomysunday Except that I don't see a single thing newly added. Just a very slight difference in re-wording that adds no new information. By the way, my first thought on reading this, taking in the title only at first, was, "Well, what do you expect from a force-sensitive resistor? They break when pressure is applied. Why else do you think they call them force-sensitive resistors? They are sensitive to force. So don't force them and they won't break!" ;) \$\endgroup\$
    – jonk
    Dec 27, 2019 at 2:36
  • \$\begingroup\$ @gloomysunday But more seriously, I'd be trying to think of a mechanical system to remove the continual force. If you have a constant force, then provide a back-force to remove it or at least get closer to removing it. Some method of balancing off the constant load. There are a variety of possibilities to consider. \$\endgroup\$
    – jonk
    Dec 27, 2019 at 2:37

1 Answer 1

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Perhaps there are better sensors to try, e.g. a strain gauge. An entire electronic scale with its strain gauge sensor can be found for ~US$10. Strain gauges have much lower drift than piezoresistors. Also look at capacitive load cells.

On the other hand, you could experiment with carbon granule piezoresistors, as used in carbon microphones, or a carbon/foam sensor. However, these also have high drift.

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  • \$\begingroup\$ Piezo is bad for dc. \$\endgroup\$
    – Scott Seidman
    Dec 27, 2019 at 2:36
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    \$\begingroup\$ @ScottSeidman, these are piezoresistors, which work at DC (or AC), not piezoelectric elements (e.g. quartz or barium titanate). \$\endgroup\$
    – DrMoishe Pippik
    Dec 27, 2019 at 2:41

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