[Valentin] wanted to experiment with 3D scanning some objects he had around the house, but says he didn’t want to buy a line laser for the project since they are pretty expensive. Fortunately, he had some random components sitting in his parts bin, and he was able to build his own line laser without spending a ton of money.
His tutorial actually covers two different methods of building line lasers, both of which use parts that you likely have on hand already.
His first build involves gluing a small square mirror to a flat platform, which he then mounted on a salvaged DC motor. Once the motor starts spinning, the cheap laser pointer he has aimed at the mirror draws a perfect line across whatever medium he is scanning.
His second line laser uses parts donated from an old hard drive that he no longer used. He removed the drive’s read head from the chassis and mounted a small mirror on the actuator arm before firing up his laser. With the laser aimed at the mirror, he applied an unspecified AC current to the motor, which caused it to oscillate and draw a line similar to his first setup.
While they might not be professionally-built scanning lasers, [Valentin’s] efforts produced some decent images, as you can see on his site.
Continue reading to see a short video of his DC motor laser line in action.
[youtube=http://www.youtube.com/watch?v=mDvAilvoy6M&feature=player_embedded&w=470]
I had to tackle this problem too once for a diy laser scanning build. If you hop on ebay you can pick up a laser line lens for about 1-4$. You can pick up an IR filter while there too!
You can create a nice laser line with a simple glass or acrylic rod
Looks like good clean fun! Add some mechanical blanking in front of the laser for some pecked line action.
Ignoring vibration from motor instability, I do wonder if these methods could provide a line with less “fuzzyness”.
maybe a small lcd display to selectivity blank out the line, or skip the line all together and spread the beam out towards something like the lcd from a photo key chain,not sure how the brightness or further spreading would hold up though.
Another motor and mirror combo to enable scanning up and down (or maybe just mount it on a servo). Some optical encoders on the motors would help with scaling I should imagine. I tried to do this with electromagnetic resonance of a lens stuck to a few magnets for the x and y and held in a frame with springs a while ago made a great projector (and scanned fairly well in low light) although I was using nine light dependant transistors in the bottom of a film canister acting as a crude pinhole camera to read the input back (only what I had to had to see if I could)
Anyone able to give some references on the principles behind the software? I’ve been interested in obtaining positional data (for a few pts) from fixed webcams and 3d scanning is essentially a higher order example of this.
AutoDesk has a beta going on right now for Capture123D that allows you to use a camera and walk around an object snapping around 60-100 pictures and then it configures them into a 3D object. It’s pretty amazing, but only seems to work really well for larger objects and the 3D meshes are a mess if you remove textures and just look at the model. I’ve been looking at building one of these setups in preparation for purchasing a 3D printer from MakerBot. I’m hoping the laser method will get me better resolution of small models that won’t require too much clean up in a 3D program like Blender.
a piece of flat acrylic gives you a visible straight beam effect laser.
a piece of acrylic cylinder gives you line beam effect laser.
I can’t help but notice he seems to have scanned his cat. Poor blind Kitty.
Great project, out of curiosity (I have nothing to really gauge this by) but how far away are we from an affordable DIY scanner that is starting to approach the quality of pro scanners?
can someone define “pretty expensive”, because dealextreme sells line laser for under 4$, and I’m pretty sure they will work better for 3d scans than these moving lasers do.
I wonder why he didn’t use a cylindrical lens. I think that’s what most of the commercial modules use.
For DIY I’ve also seen people use half inch acrylic rods to spread the laser beam out to a line. Haven’t tried it myself yet, but seems like a cheap solution if you need it _now_ since most hardware stores carry them.
After some napkin math, a motorized laser mount as above will have some nasty sine wave like effects if you take pictures in between steps of a rotating 3d scanner. Be aware, that 3d scanning using COTS stuffs requires extra calibration, usually in the form of a black and white checkerboard. Takes care of glass or plastic occlusions.
It would slow down your resolution, but if you have a 30fps webcam, you can adjust your stepper 1 tick, wait for stabilisation, take picture, and repeat. If you use a constant linear beam (ala glass rod), you can take pics as you rotate with no delay. And this scales up to the ps2 eyetoy at 60fps.
However, I can see the plus side doing it this way. A glass stick does tend to fuzz the line a bit. The rotating mirror still maintains a nice fine line. Although, I would consider putting a high rpm motor on.. Ive a hunch that fast enough (300+rpm) will reduce even the sine effect to negligible unless you use a high speed camera.
I’ve had good luck taking a piece of flat acrylic, heating it up, bending it over a form and then sanding the concave side flat on a belt sander. After a quick polish on a buffer, you have a DIY beam spreader that works quite well. The great thing is that you can control the width of the beam by changing the radius of the bend. If you go with something from dealextreme (which has a very wide beam spread and turns into a row of dots at the end BTW) then you are stuck with whatever you get. This method, although it requires that you have a few tools allows you to get it perfect for your application.
After checking out his site I wish he’ed put up a video of the accuator arm design for comparison.
@ mental2k – Don’t worry, once he gets a 3D scanner he can print as many cats as he wants.
I ment 3D printer, he always has the scanner.
Did he really scan his cat? Wouldn’t he blind the animal!?
Keyfob lasers don’t put out enough energy to blind you. Well unless you’re stupid enough to stare into it for a while. Kinda like looking at the sun.
Most cheap lasers won’t blind you, if you don’t stare into them. And that’s the problem with cats, they can stare into them, they have less of a blink reflex like us. Make sure you use really lower power <1mW lasers to play with cats.
No, for two reasons:
1.) The laser is moving and it never has constant focus at any one location (think PWM, you’re not shining at full power on any one location).
2.) The power of this unit is already pretty weak, and probably wouldn’t blind you anyway unless you stared at it for a little bit (it might disorient you and cause you to look away and blink though, or even see a burnt circle splotch for a minute or two — but again, see point #1, it shouldn’t blind you).
A CAT scan?
Look up the DAVID Laserscanner software. Another useful program is Meshlab.
What ought to work far better than a simple flat mirror on a motor is a laser scanner from an old laser printer, like the one from an HP LaserJet II. It has a highly polished, multi sided mirror driven by a stepper motor.
Keep the optics but replace the laser with a brighter laser pointer. The result should be a rather well focused line of light, at least at the distance where the line is around 8.5 inches long. Might be able to adjust the focus with some hacking of the lens positioning.
@Galane I have a few of these here.
Unfortunately the optics attenuate a lot of the 405nm light so they aren’t a lot of use for the intended laser etching project.
They are ideal however for laser projectors using red light, the attenuation is nowhere near as high.
I have a laser line lens from 12 years ago that was a simple set of 5 glass rods of about 1mm diameter each.
zero mechanics
perfume sampler filled with water = lens for a laser line without motors/vibrations/power greed.
Alternatively you can try and search for cheap laser levels using plastic lenses (chinese stores sell them for 5€ here)
Even better: some laser keychain come preloaded with a lot of caps with figures you can project; they exploit interference figures, so i expect them to be sharp and regular… amongst hearts and naked beuties, you can find some caps that draw a line you can use for scanning.
I have a laser level for hanging pictures that produces a straight-line beam – is that sufficiently cheap?
i did this with a 1/2 inch acrylic cylinder, it works pretty well.