Free As In Steins

A basic method is described for how to produce a basic 3d scanner was described on the instructables website a few years ago. It has popped up in the forums a million times, and there are some programs out there that will do a similar job.

3-D Laser Scanner - More DIY How To Projects

The basic needs for this method are described essentually as

1. The object itself. (you're got it if you want to scan it right?)

2. A laser pointer (cheap and easy to get)

3. a wine glass or something similar (cheap and easy to get)

4. a webcam or something you can use to make a movie file (relatively easy to get and cheap these days)

5. The image processor program (this uses matlab, but the comments include references to the david 3d scanner, which is freeware. You can also use the blender apparently. There is someone doing their PHD on this topic, hopefully a full integrated program will do this in future, but for now these programs work)

6. A rotating turntable. (this one is more dificult than they make it in the video)

Given this method has already been described, I figured I'd design up a turntable system that is reprap printable that you can put the object on, then follow this method to get some good 3d scans. Every part that is printable contains absolutely zero overhang, but is all smaller than 10cm by 10cm by 10cm. I know the reprap can print overhang, but in order to also make this machine producible by milling and the makerbot I did it this way. A side effect is that it is probably bigger than it has to be.

The electronics to run it is basically just the old DC motor drive curcuit. The motor I left a hole for was sized for the same motor we used in the extruder. While designing it, I didn't include a spot for an encoder piece or for it to be bolted in, so it will just fit relatively loosely into it's slot and push against the wall when it's driving the motor. I know you can get the motor without an encoder, and in this case it's probably not needed. I'll write up some code soon, which will simply be the gen 2 DC motor tester program for arduino with some minor modifications so it just goes up to speed and stays there.

The basic method of design is: DC motor drives a small gear, this gear drives a larger gear (which runs slower than the DC motor spins). The Larger gear has a rotating table on top of it that you can place your object to be scanned. The large gear rests on a bearing that allows free rotation. I used m8 bolts and nuts to keep everything locked into place

I've delierately designed the entire thing so that everything has relativey low needs for quality. For instance, the m8 holes are actually 82mm instead of 80mm. That said, before any printing is done, I recommend people who are better at designing look over things. The part I'm most worried about is the gears. Each are just simple triangle gears and probably can be fixed to work better.

And onto the design pictures themselves!

Now this is how it looks in a pretty exploded view

If you're confused, below is more detail and each part pointed out

Ok, got that? I've uploaded the 5 printable parts to the reprap site. The non printable parts are

1     6cm m8 bolt

3     3cm m8 bolts

5     m8 nuts

1     m8 bearing (the same size as used in the reprap)

1     DC motor driver, of the same size as gm3. I designed the machine based on the one I got from bits from bytes, not being aware that some others have encoders.

I hope that this design can be used and improved by everyone. Having a usable, printable turntable should make 3d scanning a bit easier with less work needed by the analysis program.

-Peter "Letsburn00" Hillier