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→A SUIVRE :-)
[[Fichier:FSR-BRANCHER3.jpg]]
[[Fichier:FSR-BRANCHER3.jpg]]
== A SUIVRE :-) ==
== Utiliser un FSR ==
=== Méthode par lecture Analogique de la tension ===
The easiest way to measure a resistive sensor is to connect one end to Power and the other to a pull-down resistor to ground. Then the point between the fixed pulldown resistor and the variable FSR resistor is connected to the analog input of a microcontroller such as an Arduino (shown).
[[FICHIER:FSR-ReadAnalog1.jpg]]
[[FICHIER:FSR-ReadAnalog2.jpg]]
For this example I'm showing it with a 5V supply but note that you can use this with a 3.3v supply just as easily. In this configuration the analog voltage reading ranges from 0V (ground) to about 5V (or about the same as the power supply voltage).
The way this works is that as the resistance of the FSR decreases, the total resistance of the FSR and the pulldown resistor decreases from about 100Kohm to 10Kohm. That means that the current flowing through both resistors increases which in turn causes the voltage across the fixed 10K resistor to increase. Its quite a trick!
xxx
This table indicates the approximate analog voltage based on the sensor force/resistance w/a 5V supply and 10K pulldown resistor.
Note that our method takes the somewhat linear resistivity but does not provide linear voltage! That's because the voltage equasion is:
'''Vo = Vcc ( R / (R + FSR) )'''
That is, the voltage is proportional to the '''inverse''' of the FSR resistance.
== Source ==
== Source ==