Hello there! I need some help on how to use the stepper motor as an attachment to the supply voltage's knob? (stepper motor connected as a potentiometer) and an IR sensor to track the rpm speed.
This is the situation, we would like to control the speed of a large scale DC motor with 120Vdc and 3A. I think that it can't be controlled directly by an arduino and some of a stepper motor driver since the DC motor's voltage is not compatible with the arduino. In my mind, I will be attaching a stepper motor on the voltage knob by a coupler. I will send an SMS to the GSM module with the desired rpm. As the IR sensor tracks/read the rpm, the stepper motor turns the knob raising the voltage until the desired rpm is reached and stops. Is it possible? I'm just a student and it's not my field by the way and I want to learn and I want to graduate. Hoping you'll help me out. Thanks.
There is a section on the forum that deals with motors. You do realise don't you that using a stepper motor to drive the controls of another motor is a very roundabout way of doing things? Why are you planning on doing things that way are you not allowed to modify connections to the larger DC motor?
You should be aware that an Arduino cannot know where a stepper motor is positioned when the Arduino starts up. The usual procedure is to move the stepper to one end of its desired travel until it triggers a limit switch and from that the Arduino knows that the motor is at the ZERO or HOME position. And arrangement like that may not be compatible with your project.
While I agree completely that using a motor to move a knob is a very "Heath Robinson" (or "Rube Goldberg") solution if you really want to pursue that option a servo might make more sense as it has built-in position control.
Control of some existing input device (button, knob...) is a valid Arduino task. In so far it makes sense to me to control the motor pot by another motor.
The choice of a stepper motor has the dis/advantage, that at power up the motor must be moved to a reference position (zero), so that the controlled motor will stop. A servo motor instead will move to a random position when powered on, until it gets a valid target position from the controller - where "valid" also could/should mean the safe zero position. Both solutions lack control while the controller is powered off, but this is just as the "uncontrolled" pot behaves as well, it will maintain its setting.
The rpm controller feedback should take into account eventual failure, so that a broken rpm signal will not be treated as a stall and the motor is not consequently driven to 100% power.
I'm just a student and it's not my field by the way and I want to learn and I want to graduate. Hoping you'll help me out. Thanks.