Hello gentlemans,
let me tell you my project.
I am controlling a DC motor using PWM by a potentiometer and a stepper motor using also a potentiometer.
my arduino is 100 meters far away from my potentiometer, so the question is how can I control it with out losing any analog data, or is it possible to control it and works perfectly?.
i cant use wireless only wiring connections.
Kind Regards in advance for reading.
Then you will want to low-pass filter at the receiving end to reduce noise - a 100nF cap from analog pin to
ground will probably be enough...
At that range, it may be time to consider PWM or a current loop.
A 555 timer can be set up to do a ratiometric comparison between two resistors. I have an example of this as a capacitive humidity/temperature sensor (actually my setup compares both a resistor and a capacitor to a known resistor). Unfortunately, it needs three wires, two for power and one for the signal.
http://epccs.org/indexes/Board/MSPM01/
Depending on how perfect you want the measurements to be the Input CaPture (ICP1 on pin 8 of Uno) may be used.
A current loop would transmit current as a function of the resistor setting. I don't have an example for this idea, but Wikipedia has some info.
Both methods improve noise immunity, so your control signal can reliably get to the MCU.
With a DC signal the main problem is damaged insulation and leakage currents, since all other
interference is transient and can be low-pass filtered out.
Also if the cable runs outside a building the risk of induced voltage spikes during storms would
warrant some protection circuitry (VDR's or TVS's). Perhaps also RF common-mode interference
could be a problem - ferrite torroid would help with that.
@MarkT I don't think it is easy to filter a long wire because it does catch RF and that can end up rectifyed by the ESD diodes on the input of the MCU, thus causing an offset. The RF may be dealt with if a range of capacitors is selected (.e.g 10uF || .1uF || 1nF), but it is a guessing game since each capacitor forms a notch filter with its ESL that has high impedance for a band of frequency and we are hoping they don't overlap to let the noise through to be rectified.