Simple Laser Scanner with Arduino

[Madtooler]

Here's another silly question: Can the EasyDriver V3.1 and Arduino Uno be used with this setup?

Thanks

[WalterMo]

Here is an overview of all the EasyDriver boards:
http://schmalzhaus.com/EasyDriver/

The newer V4 boards have some advantages over the older V3:
E.g. a better (more robust) potentiometer and the possibility to externally change the modes of microstepping. The V3 board is fixed to 1/8 microstep. Yes, it will also work.

The Arduino Uno will also work fine. If the board is with you, please tell me what kind of IC (has 8 legs) to drive the MOSFET is used, a LM 358 or a LMV 358.

I ask this because of a possible bug:
viewtopic.php?f=9&t=2261

[Madtooler]

WalterMo,

I know the V4 is overall preferred, but I readily had the v3.1 available. I think the v3.1 has the ability to be set into different step modes, but I could be wrong. Not a big deal for now either way.

With the Arduino, I didn't think the bug was with the Uno, just the previous Duemilanove.? From looking at the board, I only see one IC with 8 legs, and it is labelled MV358I. The main processor is the ATMEGA328P-PU.

I'm gonna hopefully give this a try in the next couple of days.

Thanks.

[Mike_A]

Hi Walter,
Thanks for the link to this topic.
I have followed your instructions and successfully built your Ardunio (UNO) based scanner. (with an Easystepper v4.3)
It is great !, mainly because because I can quickly change the stepper speed, this gives me more opportunity to "tweek" my camera settings. (Logitech Pro9000)
I am using a small stepper motor with a 100:1 ratio gearbox from Swarfboy. viewtopic.php?f=6&t=2435&p=14717#p14717
The laser is a 5mw Green focusable line laser that I bought here in Australia.
Thank you all for your help,
Regards,
Mike.

[WalterMo]

Hi Mike,
Good idea to separate the control console from the main hardware. So it's easier to handle.

As I read on your home page you are a well-travelled man with a lot of different skills.
Have you also flown round Troy with the paraglider before you bought the Trojan Horse?

Walter

P.S. And what next? Building a controller for planeless scanning?

[Mike_A]

Hi Walter,
Yes, I have been lucky enough to travel quite a bit, mainly for Laser Scanning /3D projects.
Troy was part of a work trip unfortunately. I was scanning some buildings in Istanbul and also an open pit mine in South West Turkey with a long range 3D scanner.
I had some time to go exploring so I went to Troy and also Gallipoli (a historic Australian WW1 military/battle site)
No Paragliding unfortunately.

Yes, Planeless is next !
I just need a repeatable start position ?
When I tried it before I used a microswitch to turn the laser on at the start of the sweep, I will try that.
Regards,
Mike.

[WalterMo]

Hi Mike,
I have reread your infos about the 3D scanners you had used for scanning of very large objects. Never before I had heard of such scanners:
viewtopic.php?f=2&t=2272&p=14913#p14913
and:
viewtopic.php?f=2&t=2272&p=14412#p14412

I have a question to the Riegl scanners which use „Time of Flight“ or „Phase Shift“. If they fire out a burst impulse with a certain frequency the „echo“ will have the same frequency if the object doesn't move (Doppler effect).
But of course the phase will change if the object isn't flat. OK.
But what happens if the air along the light path isn't homogenous? And of course it isn't along 1km or more. The density of the air is temperature depending and such variations will cause a phase shift of the light due to changes of the light velocity. Or is the combination with "Time of Flight" the nub of the matter?

Thanks,

Walter

P.S. Another question: What a feeling is it for you to work now with the very low cost DAVID scanner when you had before 250.000 USD devices at your hands?

And never before I had heard that Australian soldiers had fought at the Dardanelles in the WW1. At Wikipedia I could read that it was a long-time battle with heavy losses.

[Mike_A]

Hey Hi Walter,
Yes, these long range scanners are used worldwide,(I work for a company that sells them).
You are quite correct when you say that the air pressure and temperature affect the accuracy of the scan.
The operator normally has to enter the barometric pressure and current air temperature before each scan.
The 3D models that are created from the "Point cloud" generally average the data, so single point accuracy isn't really important.(compared to a tradition survey instrument such as a Total Station.)

The Riegl scanners are very clever, they actually have 4 echos, very handy for removing vegetation from Terrain.(in the scan )

They can also be vehicle mounted for scanning at up to 60 kph.
http://www.riegl.com/fileadmin/user_upl ... sition.pdf
Its a very exciting time in laser scanning !

EDIT-
There is a forum dedicated mainly to Mid/ long range scanning, it is independent, not sponsored by any manufacturer.
http://www.laserscanning.org.uk/forum/

The David Laser Scanner -
I have been watching this forum for quite a while and decided to build my own scanner.
I am really impressed at how simple it is !
The Software is extremely user friendly, but still seems very customizable at a more advanced level. (I haven't got there yet
The "Grab Texture" function is amazing ! ,even the "high end "Riegl scanners require camera calibration for this task.
The "Shape Fusion" is also very simple. Again, the scanners I use at work require very complicated "Targeting" (Reflective targets) and/or "cloud to cloud registration" to join scans together.

Probably most importantly, the resolution that can be achieved with the David Scanner is extraordinary !
The scanners we sell are usually around 4-6mm accuracy, no good for scanning coins etc .

The Dardanelles in the WW1, yes, it was actually where the ANZAC tradition (Australian and New Zealand Army Corp) was formed, It is "probably Australia's most important national occasion" (Wikipedia)
There is a national holiday every year in Australia to commemorate this event. (huge loss of life, on both sides, Turkish and "British" (including Aust. and NZ) Very similar to our past involvement in France, Egypt, Africa, Vietnam, (hopefully our current involvement in Afghanistan wont end up the same)

Cheers,
Mike.

[onkino93]

Hi Walter,

Congratulations on this build,

I will be building your design finally and have nearly accumulated most of the parts (I think).
I very much look forward to putting this together and performing some decent 3d scanning. Once again, well done.

James

[Mike_A]

Hi All,
I have been working on planeless scanning using the "Simple laser scanner with Arduino".
Ive build a pretty simple rig using a trigger object in front of the camera.
It works pretty nicely so far.
I am still working on reducing the "Waves" in the scan.

[gravyblue]

Hi!
Am I missing something?
Is the usb input to the arduino used in this simple setup?
If not wouldn't it be easier just to use an NE555 for the pulse train?
Doug

[WalterMo]

Yes Doug,
A NE555 as an astable multivibrator could do nearly the same.
But you should see it more from the historical side. In the beginning of this forum I had posted this circuit:
viewtopic.php?f=2&t=76&start=15
The 74HCT4060 is a perfect impulse generator because it oscillates at a rather high frequency which could be tapped at several devided-down outputs. Also the reproducibility is much better because a step switch was used.

Next:
Here I used the same IC as above but with the possibility to trigger it via an USB/RS232 adapter for planeless scanning:
viewtopic.php?f=6&t=1124

This thread now with the Arduino (without a connection to DAVID) should be a getting started for me on my way using a microcontroller for the planeless scanning.

Also, I had the impression that other guys don't liked to tinker with single (analog) components but like to learn something about (modern) microcontrollers.

Walter

P.S. There are several other circuit diagrams of other guys here on the DAVID forum. I had only referred to my posts because it was easier for me to find.

[gravyblue]

Hi Walter
I'm so sorry for all the dumb questions.
I am working through the forum, as most things are covered if you can find them.
Also, as I progress with DAVID and become more familiar, the fog is lifting too!
I attach my first subject that I've scanned, and its machined offspring
Doug

[mipu]

i just put together an arduino uno with an easydriver, a gearbox and the laser from the david starter pack. i did not manage to bring it to life so i kindly ask if you would be so nice and share your code with me?


thank you in advance and have a nice day!

[WalterMo]

The Arduino uno is compatible to the Duemilanove. At the beginning of this thread (page 1) you will find the code.

Another possibility is to build up nearly the same controller which is even suitable for planeless scanning:
viewtopic.php?f=6&t=2421

Thanks for the nice day.