First DC motor drive project

I'm going to rotate my Dell1914 monitor using a motor. Today I got the signals coming into the arduino and turning on LEDs for forward and reverse.

I have a geared DC motor. The unloaded speeds are 44rpm @12V, 88rpm @ 24V
https://www.ebay.co.uk/itm/303108845434?

I've got a dia38mm toothed pulley and a 9mm toothed belt. Which will drive onto a diameter of say 380mm giving 10:1 reduction. Hence 4-8 rpm hopefully which gives 2s -4s for the quarter turn I need.

I was going to ask about using a simple fixed voltage drive with relays and micro switches at the ends of travel vs varying the voltage with a transistor? circuit. But now I've seen some motor controllers such as this. https://www.ebay.co.uk/itm/153876126183?

To get a variable speed can I replace the variable pot with a voltage out of the arduino?

My thought was to ramp the voltage up and then reduce it after a time period to give a nicer sound to the motion. Still with a single switch to limit the travel/stop the movement in the right place.

Alternatively I was wondering about a scheme that has an earlier switch to signal start of slowdown (maybe linked to some mechanical resistance too).

Any thoughts?

I bought and use this one for a 12 volt, some 5 - 10 Amps when loaded.

Hey Railroader, thanks for the reply. Unfortunately I ignored it because I'm not using with stepper motors. That's also the reason I didn't think about the L298N stepper motor boards sitting unused on my shelf.

The board I ordered turned up, and it wasn't what I thought. The switch just physically switches polarity on the output circuit.

So a little bit more research (there is plenty of info out there!) and I discover that my dual Hbridge boards with pwm input are just what I need. I can use both halves of the board to get a total of 4A capability.

I've bought a couple more like this, Driver L298N, Driver Double Bridge H, Ideal Arduino 5899405960010 | eBay

Don’t run 2 transistor stages in parallell unles they are matched FET transistors. They will not share the current load equaly. One will pass more current then the other one and will likely be in danger.

I use that H-bridge for a 12 volt DC motor that can draw some 5 - 10 Amps! It's not a typical stepper board, rather a good DC board.!