Replacing potentiometer with Arduino-control

Hi!

So I'm controlling a fairly heavy motor for a school project and I've got the motor control to work at this point. We're using this controller for speed control. The thing is, it has to be remotecontrolled, we're doing this through an arduino. I can't seem to figure out how to replace the potentiometer with arduino control. I've figured out which cable is V+(red), Vout(yellow) and ground(black), that was fairly obvious. I know that I somehow have to use PWM and a 100K resistor because of the impedance. The on/off switch is also in the pot-meter, but I've figured out how to replace that. On the poFrom googling I've seen that a digital potentiometer might be an option, but I don't really have the time to order that in time, because we're approaching the deadline for the project.

How do I hook up the arduino to the pins on the motorcontroller that would've normally be hooked up to the potentiometer to do the speed control remotely.

Any help would be greatly apprectiated! :) I'm fairly new to electronics so I'm sorry if these are noob questions.

Bilbocious: I know that I somehow have to use PWM and a 100K resistor because of the impedance.

I don't think that is an option. The device will be detecting the variable voltage produced on the centre pin of the potentiometer as the knob is moved.

You need to replace the manual potentiometer with a digital potentiometer of the same value. Then the Arduino can control the digital pot.

Alternatively replace the motor controller with one that can take PWM signals from an Arduino.

Or (if you like Heath Robinson / Rube Goldberg) you could use the Arduino to operate a servo that rotates the knob.

...R

So Ive figured out a shoddy solution that will work!

I will control the potentiometer with a servo motor. I machined an interface between the potentiometer and the servo motor, and the servo is controlled by the arduino.

Unless you're providing volume control for an analog audio amplifier, a digital pot is usually not the answer.

You use a DAC to generate a voltage to send in place of the potentiometer wiper. Many motor controllers detect faults on the potentiometer for safety reasons, so you may need to replace the pot with a fixed value resistor (of the same value, usually 5k or 10k).

Using a digitpot would mean ensuring the controller and arduino are always powered up together to avoid phantom powering of the digipot chip (which might fry it). A DAC output (via a 10k resistor for current limiting) is simpler and more robust.

You could also low-pass filter a PWM output and use analogWrite() directly. A 10k, 10uF RC filter would be reasonable.

However the first thing to do is check the voltages used on the existing pot - probably 0 to 5V, but if not a rethink is needed.

Bilbocious: ...I've figured out which cable is V+(red), Vout(yellow) and ground(black), that was fairly obvious...

Seems obvious, but it isn´t

Yellow sends +5v to potenciometer Black sends back 0-5V to controller Red is the negative

word

I have same problem here

My scooter project (brushed 36v/1000w)

I bought this pwm controller and fried it with some tests. Then I bought a bigger pwm controller like the one you using, but still without success to drive it from Arduino.

First I plug the scooter throttle (same of e-bikes) to my Arduino Uno, read the parameters in analog pin and convert to 0-255 analog write. Tested with a multimeter and with some adjusts it works great: outs 0 to 5v "correctly"

Then I took 3 1,5v batteries in series (4,5v) and tested on pwm controller: With default connections (36v batteries connected, motor connected and default potenciometer connect and running on middle velocity I pluged the negative of 4,5v batteries on red of potenciometer and softly put the positive on the middle pin of potenciometer. It increases the motor rotation, indicating it works.

Then I replace the 4,5v batteries connections to GND and analog +5v of my Arduino. And fried it on moment I plug. Goodbye to my Uno.

Now I have no ideas what to do. When I plug the throttle replacing the potenciometer (just pluging same pins) the motor wont be on zero. I thing the throttle sends from 0,8 to 5v... so my scooter never stops...

I´ve heard there is a way to do that: replace the pot of pwm controller for a chip (with 4 or 8 channels and manage it with arduino.

Like this https://www.sparkfun.com/products/10613

I think I´ll do that, but my skills are almost nothing haha