I have a question about voltage dividers. Are they always connected in this order : 5V->variable resistor->split into microcontroller input & fixed resistor? Would the voltage divider work if it were connected like this : 5V->fixed resistor->split into microcontroller & variable resistor. I'm trying to monitor the voltage at the input. Would changing the two around matter?
Nope, doesn't matter. But why not just use a single pot and connect the microcontroller to the wiper?
Well a fixed resistor in a variable/fixed series voltage divider string will define the lowest or highest voltage the arduino will be able to detect depending if the fixed resistor is on the top or bottom of the series string.
As Keith said why don't you just use a three terminal pot so you can dial any any voltage you want in the 0-5vdc range?
Lefty
What are you trying to do ?
For full range pot across the rails.
If you are looking for a reference for instance connecting suitable resistors each side of the pot will give the pot better resolution.
Just a thought though , if the UNO, the chip has a 3.3 supply, a pot across 5v rail could exceed 3.3 so in this case you need to check you do not exceed the electrical specs for input pin verses Vcc voltage.
The reason I'm not using a pot is because the variable resistor that I'm using is actually a force sensitive resistor (w/ 3 pins).
Ok
The circuit in your original post should work over a limited range but may not be linear.
Normally the reason for a resistor in the legs of a pot is to adjust the operating point and range of the pot.
A resistor from the wiper to the input pin should have no effect on the divider operation it just limits current into the input pin.
I am unfamiliar with 3 terminal force sensors, but a quick google indicates they function electrically like a pot.
I would try a diagram but do not know how.