Budget Scanner Mover for the Inspire

I build a simple and budget mover for my Inspire.
It allows the scanner to be mounted and move up and down and also tilt the scanner.
The project was strictly focused on budget, so i used mostly parts i already had.
So there are some drawback and known issues i will mention later.
Here is a short video:

The main idea was to have something moving the scanner automatically when to object to scan was on a turntable.
But it should not only move up and down it should also tilt the scanner to allow better scanning of overhangs and undercuts.
Doing this by hand can be challenging, because i tend to tilt to much and to fast.

Most parts where printed in PLA.
I used a aluminium U-profile with at M8 threaded rod as linear actor driven by a NEMA17 stepper motor.

The tilt part is directly driven by a “DS3218 Pro” (not sure if it is a genuine one).

The controller is based on a rp2040 (zero), a DRV8825 stepper driver and a lot of hot glue after wire wrapping and soldering. Doesn’t looks so nice.


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(sorry, i had to put the attachment into single replys)

The controller uses some gcode like language for programming, but parts of the program are executed on the host computer right now (like pause commands).
I created a simple HTML frontend to create the gcode with something like an editor.

It was also possible to use the WebSerialAPI to directly communicate with the rp2040, and send the commands to the mover.

My fist intention was to send command the high and angle to the device.
The when the scanner is moving past the object and wants to continuously point to the same spot, the angle movement is not linear.
So i decided to do the angle calculation in the controller and send the height (Z) auf the actor and height (Y) and horizontal distance (X) auf the target spot.
This results in short and very simple gcode.

Lessons learned:

  • adding a emergency stop switch which disables the stepper and the Servo

Known issues:
The M8 rod (1m long) was not the best idea because it requires to be turned quite fast as 1 turn only gives 1.25mm in height. I can go up to 15mm/s from the stepper, but the whole thing is shaking a lot then. 7mm/s is working fine and works good enough for scanning humans.
Smaller object should go even slower.

The U-Profile was not easy to mount on a Base. Next time i would try to T-Slot profiles, but there it could be hard find a place for the stepper.

For the Servo i first used a MG996R, which seamed to work nice, but the resolution was not that good and the angle change where to jerky.
The DS3218 Pro works better, has around 0.5 degree resolution. It works so far without issues but i still get warnings from RevoScan to move steady. :slight_smile:
I used a 180 degree version of the servo. The movement of the Tilt Part is limited to 45 degree up and 65 degree down. It might be interesting to use a 270 degree servo and some transmission to get a slower and smoother movement.
But the space is very limited, because you need to keep the position of the USB plug in mind.

There is no synchronization with the turntable. At least a trigger signal could have been interesting. But due to the hot glue i used …

The code is still a bit quick and dirty with a lot of hardcoded values.