I would like to measure the force with an fsr sensor connected to an Arduino MEGA 2560.
I have found some tutorials on the internet, and it should look like this:
https://cdn-learn.adafruit.com/assets/a … 1396762989
My question is why do we need the resistor connected to the ground?Couldn’t it work without the resistor?
Thank you!
Without the resistor to ground it will read 5V all the time. The Arduino has a high impedance input, and will draw next to no current. Without current flow, there will be no voltage dropped across he FSR and nothing to measure. The resistor to ground provides a current path. It’s called a voltage divider.
Thank you for your answer. But if I have an additional resistor, this only raises the impedance, doesn’t?
An other question: How can I determine the value of the resistor?
If you were adding the resistor in series with the input, then it would increase the input impedance. However, the voltage divider resistor is effectively in parallel with the input, which lowers the impedance. The FSR hookup guide at https://learn.sparkfun.com/tutorials/fo … okup-guide explains how to choose a resistor.
