Use PWM for DC motor?

I've read tutorials and comments on forums that you don't want to connect your DC motor directly to PWM pins on an Arduino Nano because of the following:

  1. Reverse voltage
  2. Too much amp draw

I have a DC N20 motor that is 5V 70mA. What if I double up the PWM pins on each leg of the motor and bridge a diode across? Would it still not be a good design? Or is it ok?

I currently have a DRV8833 driver set up, they are relatively cheap from aliexpress but I am constrained on space for my project and trying to simplify my circuit as much as possible. Please let me know if you have any ideas. I need to be able to control the DC motor in both directions. Speed is not necessary since it's geared anyway.

Use a transistor to drive the motor.

If I use a transistor, I won't be able to reverse the direction of the motor, correct? Also, going with the motto of using least possible parts, is my original theory of doubling up PWM pins possible?

You can reverse the motor with a relay and then control the speed via the transistor driver.

How much room do you have available?

This might meet your space criteria:

https://www.technobotsonline.com/pololu-motor-driver-1.7a-drv8838.html

With

shai:
If I use a transistor, I won't be able to reverse the direction of the motor, correct? Also, going with the motto of using least possible parts, is my original theory of doubling up PWM pins possible?

You can quite easily reverse your DC Motor polarity with transistors. There's no need to use relays as they consume space and are quite slow in operation.

Instead, you should go with transistors like BC547 or 75N75 etc. and yeah it's not recommended to use DC Motor directly with PWM Pins as it will burnt out your pins because of back emf.

MichaelABC1:
You can quite easily reverse your DC Motor polarity with transistors. There’s no need to use relays as they consume space and are quite slow in operation.

Relays are more than fast enough for direction reversals.

Instead, you should go with transistors like BC547 or 75N75 etc.

They have their uses but I’d not suggest them for motor use, let alone trying to build one’s own H-bridge with them. Especially with dirt cheap ready made motor drivers out there.

I have always used the L293D chip, small easy to wire and seemingly pretty bullet proof. They are available as a add on module but I typically buy the chip and a socket and do it myself. Way cheaper and less hassle than trying to build my own H bridge and they drive 2 motors forward and reverse.

Use either bottom right H bridge in Larryd photo, or buy a driver board.

These a 2 neat examples that have a small footprint and pricetag (less than $10).