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View Full Version : Flex (bend) sensors: depends on how you bend them...



Researcher
01-24-2009, 06:26 AM
Apparently bend sensors read differently on the top vs. the bottom.
Once bent from the top the readings are more sensitive.
Anyone know of any that yield the same reading if bent up and down?

Researcher
01-24-2009, 03:14 PM
bi-directional bend sensors
http://www.imagesco.com/sensors/flex-sensor.html

robologist
01-24-2009, 11:47 PM
Don't have any idea of how to make the readings equivalent between "bending in" and bending out". I have some similar sensors, probably the only thing you can do is correct for the readings in software.

Researcher
01-25-2009, 09:13 AM
I think it relates to the acetate film they place on the bottom and not the top.
I have the bi-directional on order, I bet the film is equal on both sides.

Adrenalynn
01-25-2009, 03:49 PM
I think you'll find that it's the density of carbon. The way they work in short: As the sensor bends the carbon is stretched or compressed. The current passes through the carbon, and as you stretch it out you raise the resistance, and as you compress the carbon you lower it.

Researcher
01-25-2009, 06:51 PM
Are you suggesting bending upwards from level is compressing and bending downwards from level is stretching? I would think a bend in either direction from level would generate stretch and raise resistance. However, the only difference is that one side has more plastic laminate than the other. I would argue that the substrate is playing a role in these differences.