Rotary Indexer - Stepper Motor Edition

There is an early post describing a manual rotary indexer, and the discussion on it was dominated by ideas about making it electronic. So I made an electronic indexer.

I cut the gears, mount plates, and some washers from PG medium acrylic. The gears perform adequately, but not great. The wooden “holders” are cut from PG medium draftboard. The googly eyes are functional: they keep the axles from working their way out. More pictures:

The electronics are all standard hobby kit pieces except for the rubber pillar wheels which I salvaged from an old printer. Very detailed dimensions of the stepper motor are available online making designing the mount plates much easier. I’m using a Raspberry Pi Zero as the Brain ™ for right now but may switch to either the Arduino clone or the ESP8266 that I have laying around. (For me, the software & electronics are the easy part, and the laser is the hard part.) I connect to the Brain ™ using my computer, and when I type in an angle, the motor turns through that angle. Here’s a 42 second clip of me doing that, if you’re into that sort of thing:

Practical usage is a bit of a trick: just because the pillar wheels turn 15° doesn’t mean the object on top of them turn 15°! So you need to know the radius of the object you are turning in order to turn it the amount you desire. I’ll report back once I experiment with using it a bit more.


Wow! Great work and concept.

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Sweeeeeet! :sunglasses:

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Well of course. Googly eyes are critical :smile:

Love it!


Googly eyes on SNL


Awesome project.
Need a small container to hold all the electronics so the garbage flying around in there does not gunk it up.

Saw one a bit ago that moved down with the cross bar pushing the rig and turning the scored item as it went.
That would use a standard file but is not for the Glowforge, since it does not just go down from top all the time.

Since yours does not roll down, it may get tricky. Suppose you can Color code the various etches for order of burn, and pile on top of each other. Etch, turn - etch next - etc.

Let us know how it works out for you.

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Power supply through the slot ?
Assuming you’ve got a pro, of course !


Also, I don’t recommend putting a battery pack inside the laser.

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I’m assuming I shall do something similar with the vacuum tube for an internal vacuum bed, mounted in place of the crumb tray. It will probably be several tubes in parallel through the slot.

I like it!
How are you stopping the gantry from moving front to back as your rotary turns? If you take off the belt, are you tapping your Pi into the main control board?