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my tilting motorized laser mount

my tilting motorized laser mount

Postby nicanor76 » Wed Jun 18, 2008 4:28 am

I've had this idea for awhile ever since I came across this 3d scanning, had some time the past couple days so I decided to build it. I decided to use foamcore since I didn't want to spend too much money into it. I never did any real electronics nor know how to program a PIC controller, so I ended up just using switches and buttons connected between the battery and the motor (which came off a broken CD drive, the one that opens/closes the tray).

I got the concept from my CNC build for moving the axis boards around:
1-attach a thread to a motor
2-attach a board to the (nylon wing)nut in the middle of the thread
(2a)-other side of board pivots on other end (where the laser is mounted on)
3-spin the motor--> spin the thread--> make the board move up and down
(3a)-change the battery polarity--> spin the motor the other direction

Video, should explain things better than just the pictures:
http://www.youtube.com/watch?v=3ATmJpTMuTg

It has a control knob to control the speed, so it can be fast for setup to slow for scanning. I put a nut on the bottom so it can be attached to any camera tripod as well. The build cost around $15, mostly went towards the buttons and switches. I had thread, nuts and foamcore laying around. I also used an inside of a pen (metal tube) as the pivot point at front, and an old skatebaord bearing on top for the upper thread support mount.

Video, should explain things better than just the pictures:
http://www.youtube.com/watch?v=3ATmJpTMuTg
Attachments
scanner1b.JPG
motorized laser mount with remote
scanner1c.JPG
rear shot of my motorized laser mount with remote
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well done

Postby hal » Thu Jun 19, 2008 9:07 am

Well done nicanor76,

it's a good and light construction. Only a question: the verical axis movements (rolling) don't disturb your scan results? If you can, please post some scans of yours. Thanks for sharing,

Mattia
PC: DELL Alienware 17, Intel I7-4710MQ, 32 Gb Ram, AMD Radeon R9 M290X 4GB.
SO: Win 8.1 64Bit.
CAMs: USB 3.0 CMOS B/N (1280x960, 60 fps).
LENS: 12 mm.
PROJECTOR: DAVID SLS1 ACER K11.
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Postby nicanor76 » Sat Jul 05, 2008 5:57 pm

I finally got results, been busy. I made a quick video (laser scanning in general). The scanning done on this was a little hurried so can get better results if I took the time and slowed down the laser movement some more.

Will post real screen shots soon on a new test subject once I play around with 2.0

http://www.youtube.com/watch?v=Rw_YYI8jPD8
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just a question

Postby tetrion » Mon Jul 21, 2008 10:19 am

what did you use to mount the thread to the motor, I want to build something similar to this, but am stuck on how to mount the thread to the motor.... my idea is instead of a pivoting platform, the whole platform moves up and down, guided by frame rails, using the same process of the thread....

Any suggestions would be greatly appreciated.
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Postby MagWeb » Mon Jul 21, 2008 10:39 am

Hi,

a good lowcost way to join motor and thread is a short piece of air hose, fixed with two hose clamps.

Gunter
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Postby tetrion » Tue Jul 22, 2008 12:12 am

Thanks for the tip Gunter,

What would you suggest is the best scanning technique to reduce noise, and get the best result.

Pivoting laser platform, such as this type of scanning, or a platform that doesn't pivot but rather physically moves up and down vertically?

The reason why I ask, is that I have built a pivoting type of scanner, but get a lot of noise in my end result. (I actually posted a few pics of my setup in an earlier post)

Thanks

Tetrion
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Postby nicanor76 » Tue Jul 22, 2008 4:29 am

the clamped hose is what most DIY CNC guys do, and the method I used for my CNC also. But for this one I just used a plastic glue gun, works fine since it's a slow turning motor with minimal force load on it.

I never tried to scan by moving the laser itself on a parallel movement (instead of a pivot point), so am curious myself if that's better. Once I finish my CNC I'll probably redo this mount design using wood.
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Postby MagWeb » Tue Jul 22, 2008 7:25 am

Hi,
What would you suggest is the best scanning technique to reduce noise, and get the best result.


Hm, as many things using DAVID, that depends on the things you want to do. You allways have to find the right balance for your claims:

Most of us use the rotating(tilting) lasermovement (little hardware, maybe a kitchen timer as Hal suggested). This way owns the opportunity that the intersectionangle is nearly constant as long as your near the same distance to the object as the cam has. (compare graphic: green, orange, blue)

Moving the laser linear, means the intersectionangle falls as you get nearer to the cam.
But this linear movement owns some advantages. The angle the laser hits the corner or the object or a mirror,(THAT IS NOT THE INTERSECTIONANGLE) is constant and predictable. So that way may play some part in future setups.

Some other hint:
Most of us choose a rightangled viewingline of the cam on the corner/object's vertical. For, if you use webcams, a cam is cheaper than a good focusable laser: You can create the intersectionangle also in the way shown in graphic 4: rightangled laser and angled cam (so you can use a second from above)

The reason why I ask, is that I have built a pivoting type of scanner, but get a lot of noise in my end result.


I think you will not improve this by building a linear motion setup. The cause for the noise should be some other. Maybe too quick, maybe to bright ambient light, maybe wrong cam settings, maybe too thick line....


Hope this info helps
Gunter
Attachments
Angles.jpg
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Postby velleca55 » Tue Jul 22, 2008 5:48 pm

Bag your pardon for the intromission ... (and bad english) ...

But I'm still to fix my laser in my CNC machine to use David ...

With the parallel movement I lose something ? ... Or is only a consideration ...

David works better if the laser rotate around a point ? ...

.
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Postby MagWeb » Tue Jul 22, 2008 6:00 pm

Hi,

in my beginning I mounted my DAVID on my router too ( till I decided to build an own stepper driven device). This system tilted the laser.
http://www.david-laserscanner.com/forum/viewtopic.php?p=649&highlight=#649

Linear movement works, too. But the intersectionangel gets worse as the laser gets nearer to the cam (and if it is toooo near the quality drops for the laser gets more and more a straight line with only a little profile= bad information for DAVID)

Gunter
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Postby nicanor76 » Tue Jul 22, 2008 6:10 pm

also to add, you may get bad results or static if you move your laser to a different position on the same scan (slight potential alignment board problem that maybe an unfixable human error). That's why some people save the results after only 1 laser scan then restart a fresh capture, then combine everything in Fusion
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Postby MagWeb » Tue Jul 22, 2008 6:20 pm

Sorry nicanor,

thats not quite right:
If you move your laser you get a new camline while you move.
The problem you are talking about appears not caused by a movement but from the different linedirection. Once coming from above they appeare as a V. From below as a ^ . So inaccuracies are calculated to the other direction.

Hope you got me,

Gunter
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Postby velleca55 » Tue Jul 22, 2008 7:23 pm

At the end if I made one good pass I'm OK ...

And for a new pass I made a new scan ...

But if I made two passes for scan, one going and one returning, changing the angle (one come above, other come from down) have problems ?..

I think no ...

And to put the laser in deferents positions, at beginning and the and of the support, but in the same parallel axis, can change something ?...

I think no ... but what you think ...
Attachments
P7220001 (Small).JPG
CNCsetup 2 (Small).jpg
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Postby MagWeb » Tue Jul 22, 2008 7:54 pm

Hi,

there might be problems, but that depends on the accuracy of your corner AND your calibration. I allready reached perfect setups and calibrations, you do not notice any differences of the two passes within a single file.

To see the effect:
Load the Angelscan.zip from the downloadpage. The movie shows two passes, one from above one from below. If you grab them with switched off backgroundfilter, you can see that the scan of the planes is a little displaced in the second pass.

You can avoid this disturbance if you save the two passes in separate files.

Gunter
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Postby velleca55 » Tue Jul 22, 2008 7:56 pm

Scuseme ... but now I understand (my english is not good) ...

The problem with th parallel passes are when near the cam ... Now I understand ...

And now I see the movements you construct on your laser setup ...

I have read your post more than year ago ... :oops: ... but forget the mechanism to rotate the laser, without "Y" movements ... looking better your setup I understand my misunderstanding ... :lol: ...

Forget my considerations ...

In resume ... I'll try to put the line laser out of the line cam ... better the cam out of the machine in respect with the angles needs to scan ... and if the parallel movements don't work, so made something like you do ...

And OK for the explanation of the two passes in a single scan ... :wink: ...

Thanks Gunter.

Donato.
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