The title says it all. I'm working on a project that requires me to power a brushed DC motor that can reverse directions and change speeds. Everything is controlled by Arduino, but an external battery powers the motor. The Arduino steps in between in order to control power flowing to the motor. I'm new to electronics and this is my first project, so I'm hoping for some guidance from the EE community here.
Is my approach of using a MOSFET to control the speed of the motor and a relay (since it can reverse voltage) to control the direction a reasonable one?
How would this look in a circuit diagram if it could work at all?
I hope this is sufficient information, but if you need more details, please most a comment and I will elaborate. If you have any other approaches you'd like to share, please do.
Edit: The suggested duplicate "question" doesn't help me or answer my question because I don't see a question and I don't see how the answers address every part of the question I'm asking here. My main question specifically asks if I can use a transistor and a relay in the same circuit to control the direction and speed of a motor. I'd also like to know how I could implement this by seeing a circuit diagram.
Best Answer
Yes, you can use a relay for direction reversing of a brushed DC motor. It would use a DPDT relay as shown in the diagram below. And yes, at the same time you can use an N-Channel MOSFET transistor to control the speed of the motor by driving the MOSFET with a high speed PWM signal. The duty cycle of the PWM would control the motor speed.
With the proper selection of MOSFET you would be able to drive the MOSFET from the PWM output from your Arduino. The direction relay coil is shown as using the same voltage as that used to power the motor. If the relay coil was a different voltage it could be connected to a separate voltage rail.