Animation with Stepper Linear Actuators

[Mark W]

Pulling this one over from the DCC/Electronics forum as I'm now getting to the building part. 

To quickly recap, I found a bunch of super cheap, super micro Stepper Motor driven Linear Actuators.

 



I had a hell of a time getting the pins soldered without destroying the unit, but practice makes perfect, and a few sacrificial steppers helped iron out some code later on. 

After some experimentation, I was able to get a working mock-up of an animated N Scale 3D Printed Baler (graciously provided by Baldylox Designs)





And that brings us up to speed with today's latest, mounting the unit and attaching stuff to the nut. 

The nut on the medium actuators is a little plastic square with a single nub, kinda visible here. Through experimenting, even with double phase control, these micro steppers don't have much torque and like to stall way too easily.  After a few more experiments, I think I found a way to reliably attach a drive arm to the nut to minimize stalling, shown below. 



And for those who saw the other thread, yes, that's the big one in the background, just arrived!   I've only played with it about 5 minutes, but I'm definitely impressed with it so far!!  It can go fast, it can go slow, plenty of torque, and much more flexible mounting options!

Next up is mounting this one to my Roca Free-moN module and finally get those crossing arms animated!  More to come.

[Mark W]

Took a Dremel to one of the super micro actuators and cut off the bracket, leaving me with one heck of a tiny stepper motor!  Small enough, and slow enough, to directly drive an N Scale Windmill.



The only downside is this windmill and this stepper match each other too closely.  Stepper has 20 steps per rotation, at 18 degrees each; windmill has 18 blades at 20 degrees.  So I'm getting quite a bit of the stroboscopic effect in that the rotation appears choppy or that the windmill is just vibrating rather than actually rotating.

You can see here, the colored blade rotation looks great, but if you focus on the non-colored blades, choppy chop. 


I think if I make a 12 blade windmill that will solve the strobing effect.

[Mark W]

Got a working forklift. 

[Scottl]

This is really amazing work.

[newt749]

It looks like you could use the micro motor to turn an airplane prop. They may not have much torque but the ability to control their movement certainly leads to a lot of possibilities.

Great work and inspiring.

Rob

[nkalanaga]

I doubt that it could make a plane fly, but an N scale plane, hanging from a string, might very well pull itself around a circle.

[RBrodzinsky]

Fantastic work, Mark.  So, how many steppers can run off a single Arduino?

[peteski]

I doubt that it could make a plane fly, but an N scale plane, hanging from a string, might very well pull itself around a circle.

The max. RPMs of a stepper like that are way too slow to even produce motion blur of a 2-4 blade propeller, or produce any appreciable air movement.

[nkalanaga]

Darn.  I was thinking of the stepper motors on the printers at my last job.  Admittedly they were a lot bigger, but they could also move the paper very quickly.  I always thought the only limit on the speed was how fast the control signals could be repeated.

[davefoxx]

The max. RPMs of a stepper like that are way too slow to even produce motion blur of a 2-4 blade propeller, or produce any appreciable air movement.

[railbuilderdave]

I like what you have done thus far. I can really see these used in so many ways.  I would love to know where you found these and if they have more.

Dave

[peteski]

I like what you have done thus far. I can really see these used in so many ways.  I would love to know where you found these and if they have more.

Dave

If you click on the link to Mark's other thread (link is in the initial post of this thread) and read the other thread, Mark provided links to the specific eBay auction listings for the motors.

[railbuilderdave]

If you click on the link to Mark's other thread (link is in the initial post of this thread) and read the other thread, Mark provided links to the specific eBay auction listings for the motors.

Thank you for that. I do see there are a lot of these on eBay and I'm sure I'll be able to find all kinds of ways to use these little guys.

Thanks,
Dave

[Mark W]

Fantastic work, Mark.  So, how many steppers can run off a single Arduino?

Thanks Rick.  These steppers take 4 pins, some take 5.  The Uno can probably handle 3 steppers directly.  I'm not sure if shift-registers would work, but that would significantly increase capacity. 
I plan on using the smaller trinket boards that are a few dollars each, so will mostly be one board per stepper.