I have two adjustable DC power supply boards that I want to use to control a DC motor (just the speed, direction is always the same). The controllers use the following:
Both of them use potentiometers to adjust the output:
1 uses 4k
2 uses 10K
The idea is to hook Arduino controlled input in place of the potentiometer to be able to control the output voltage of the controller. As for transistors I have some spare LM317 available as well as ULN 2003 (however would like to retain them to controll my little stepper motors). Any ideas?
Is there some reason that PWM from the Arduino will not control your motors without this power supply like the rest of the world does it?
If you must or insist on doing it this way, look at digital potentiometers. Or if you only care about certain values, you could use a CD4066 to switch in resistors in place of the potentiometer.
You would be better off powering the motors at full voltage and controlling the motor using a transistor (MOSFET or other, depends on current rating) and using a PWM output to control speed. If you lower the voltage to the motor to control speed you are also lowering the torque and you will have less control than if you can supply the motor the full voltage and control the speed by turning that full voltage on and off with PWM.
The motor runs at 2.3 amps, 24V and I need it to run at high torques. Any suggestion for a robust MOSFET that would cope with this power for long working times (100s of hours).