Very simple:

You need, a stepper motor.
a 3d printer
those 2 printed parts.
a line laser i used my dewalt construction one!
and a android cellphone or tablet with scan3doid (around 5$)

https://play.google.com/store/apps/details?id=com.gsohler.scan3droid&hl=fr_CA

Then I suggest unplugging x motor from your 3d printer and plug your new scanner's one.

Now you have to determine how many "x mm" makes a complete revolution of the stepper. To do it, I used pronterface and counted the number of mm +1 before one complete revolution. for me it was 40mm

Then send g28 x0 and make sure you manually hit the x end stop.

Send a command G1 x40 f20
the x is the one you just determined earlier. and the f is the speed... If it goes too fast or too slow, play with it.

When you are ready, use the app to record video and follow the instructions of the app. The cell phone needs to be well fixed.