Hello All. I am relatively new to electronics in general and the Arduino in particular (but I am learning). I have configured and programmed an Uno R3 with a motor controller to run a 12vDC motor at a speed set by the Arduino program. I would like to add a pot to the circuit. But I don’t want the pot to “actively” control the motor speed (by turning the knob). I want to use the pot to set the max speed for the motor. So when the program starts, it reads the pot once, figures out the max speed, and starts the motor. My question is, there are pots that come in varying levels of resistance (e.g., 100 ohm, 200 ohm, 10k ohm, etc). Which pot/resistance is right for this application? Does it even matter?
Thanks.
Use a 10k. Easy to find, cheap and solves the problem.
The idea is to measure a voltage variation, you don't want too much current going to the pin (remember that 20mA is a safe limit to Arduino R3). So, you want a resistance big enough to result in a minimum current and yet have the voltage detected.
Terrific. Got it. I’ll give it a try.
Thanks for the quick reply!
10K LINEAR (B) TAPER
or you’ll get unexpected non linear control !
It should be wired like this.
If clockwise rotation decreases the voltage on the arduino pin, and you want it to increase for clockwise, then swap 5v and Gnd connections.
C1 is there to reduce noise. You could also reduce the effect of any noise by doing analogRead() N times, summing the values, and then divide the sum of the values by N.
The value of C1 isn't critical. 100nF is the minimum I'd use. If you use a polarised capacitor, then connect the + terminal of the capacitor to pin 2 of the pot.
Don't use a pot too much more than 10k ohms (a 1M pot would be a bad idea), because the ADC has some "issues" if the input impedance gets too high.
As previous, speed will change with load changes unless provision made .
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