------Question for ESS102 Please Put your question below------
Hi, Everyone,
I am new in touch (force) sensors. I want to start a study about the force of light touches of human fingers. Somebody suggested the finger inserts 5 to 10 grams of force when making a light touch. Can a low cost sensor, such as the Tekscan ESS102 or A301, measure this force? The standard force range of these sensors are 0 to 1 lb. The range of force I am interested is definitely near the lower limit of these sensor. Are they able to pick up the light touches reliably? How about the Honeywell FMAMSDXX005WCSC3, which also has a range of 0 to 1 lb, but a couple of time more expansive?
Thank you!
You may also want to consider a Force Sensing Resistor (FSR).
You set them up in series with a resistor in a voltage divider and the output goes to the Analog to Digital Converter of a microcontroller.
Part Number: 30-81794 as one example of an FSR
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Hi liul7788,
If you are trying to reasonably accurately measure the amount of force applied rather than simply detect that some amount of force is being applied, then the Honeywell FMAMSDXX005WCSC3 is the better option.
The other parts mentioned can give an indication that a force has been applied, and give an output somewhat proportional to the amount of force applied, but they are not well suited to give you an accurate absolute magnitude of that applied force.
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Thank you for your advice, David!
FMAMSDXX005WCSC3 has a 5 N force range. This is the smallest range in the FMA series. Do you happen to know whether this sensor can be set to emphasis light touch force, like 100 mN?
Best
Lei
Hi liul7788,
The output of this sensor is via SPI, giving a digital representation of the force measured. It cannot be adjusted to emphasize any particular range. Each LSB of the output represents about 0.01% of the 5N range, or 0.05N per bit. The sensor’s output is only the middle 60% of the possible digital values, with 20% representing a force of 0.00N and 80% representing 5.00N.
Please see this technical note on how the SPI communication works with this sensor.
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After looking through some more of the documentation for the FMAMSDXX005WCSC3, I did find an additional technical note, titled MicroForce Sensor Coupling, which on page 4 describes how one might use leverage with a hinged arm to amplify your light force so as to increase the resolution of your measurements.
Here’s the diagram from page 4 which shows how one might implement this:
And here’s the relevant formula one would use with this diagram:
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Wow! Thank you for digging out this trick! It’s so simple and easy to implement! 
Best!
Lei
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