Author Topic: IR Laser?  (Read 42339 times)

Offline gabort

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Reply #15 on: February 03, 2008, 05:54:06 PM
The wavelength is 850nm.

The wiimote detects the laser (when I shine it directly into it), so the wavelength is OK. In addition, all my IR pens that also work fine make use of leds of this wavelength.

I think the problem in my case is power. I'm not sure, what wavelength your mouse operates at...



Offline gabort

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Reply #16 on: February 03, 2008, 06:29:40 PM
I also checked, to see if my MS Sidewinder mouse would show up on the Wiimote. It does not. Not even if you shine it directly into the camera. So it is probably the wrong wavelength... Extapolating this to the reality of manufacturing and component sourcing, we have a 95% chance that all laser mice are about the same.




Offline Wartt Hog

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Reply #17 on: February 05, 2008, 06:45:53 PM
I absolutely love this wiiteboard (groan) idea!  I'm not enough of an engineer to try it, but please allow me to add my two cents.

Firstly, am I right in saying that troy59 and gabort are proposing two different ideas?  troy59's design has the wiimote aimed at him on the couch whereas gabort is talking about producing an IR spot on the whiteboard from his couch, just like the original movie but using reflected laser light instead of direct LED light.  Is this correct?

I think both ideas are awesome but for different reasons.  troy59, would you get the same effect (minus laser pointer) if you just put more power LEDs in your Wii sensor bar, spread them further apart, and use the wiimote as your "pen"?  If this works, it might be possible to write a downloadable whiteboard program for existing Wiis!  ... Maybe it's already been done, I don't know.

gabort, I think you're on to something.  It's got to be possible!  How far was your laser from the reflective surface?  I would expect a light-coloured, non-shiny, rough surface like white bedsheets to work the best.  For the record, this whiteboard would be cool enough I would wear safety glasses to use it.  :)  If the parallel-red-laser idea doesn't work, you could also just leave the IR laser on all the time, draw some kind of cursor, and use the "right-click" idea for drawing.

Here's a way out there idea because I don't know what I'm talking about:  I'm guessing the laser is dangerous because all the light is in phase, right?  What if your pen was several weak lasers mounted in parallel?  The lasers would likely be out of phase from each other, but if they weren't aimed at exactly the same spot, the combined blob of IR light may be detectable by the wiimote.  If this idea's dumb, hopefully it inspires someone smarter than me.  :)



Offline troy59

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Reply #18 on: February 06, 2008, 10:46:30 AM
no, no, i get you, that could work because the wiimote only sees blobs(it has a sensitivity thing on the actual wii and the wii mote shows up as two blobs) so if you had a couple of week lasers, then it would make one big blob, and then the wiimote would read it. Its a good idea, just needs to be put in to real life



Offline gabort

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Reply #19 on: February 07, 2008, 05:08:06 PM
These are some interesting suggestions, and it would really have been a nice thing to have a laser pointer to draw with. Still, it seems that this particular device is not suited for this use.

The Wiimote was originally designed to detect the IR light of ten (10) leds glaring at it from some distance away. That's two BIG blobs of light which are very bright indeed. This is why my 20mA led IR pen effectively failed on my first try: it was not bright enough.

Using 3x100mA leds in my new pens, it works like a dream.

Now to lasers:

I had the laser pen and the wiimote touching... each at an angle of 45 degrees to a sheet of paper on the table, and it would not get detected... Only, if I shone the light directly into the wiimote, was there a blimp.

Lasers are also expensive, and as such, are no longer fitting to the "cheap and easy" approach we were hoping for. They are expensive. The 2mA laser module I bought for this test cost me 30 Euros. Three of these would be quite expensive. A 30mW similar module costs around 150 EUR, and I would have concenrs for eye safety using it.

2. While the problem with lasers might be that they are "in phase", I would expect that light density has to do with it as well. A laser beam directs its output with very little spread, while a led will distribute it at a 30-50 degree cone. So the light energy hitting the retina if you hit the eye would be MUCH stronger. Also, since you can not see IR light, there would be no blink reflex. Also, should you be wearing glasses, the intensity might be increased severely again.

It is for these reasons, that I say I won't go further with this now. Even if 3 lasers will be bright enough to get detected, or a 30mW laser does the job, it would no longer be a budget solution, and I would not leave my kid alone with it in a room.



Offline Wartt Hog

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Reply #20 on: February 07, 2008, 06:38:18 PM
<Sigh>  You make a good argument.  It's a shame though.  Anyway, thanks for forking out the 30 Euros so we could all feel someone gave it a good shot.

From Tom



Offline priegel

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Reply #21 on: March 04, 2008, 12:53:41 AM
anyone tried using the IR lasers in Laser challenge/tagging equipment? the older equipment goes cheap on ebay ($10) you only have to disable the pulses (coded signals).
I expect the Wii to be easily able to detect the light intensity of even the weaker IR lasers used here, its main problem is the size of the dot. this could be solved with one of those lens bits they sell with the cheap laser pointers which turn your laser dot into a larger shape. anyone has given this a shot?




Offline inio

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Reply #22 on: March 05, 2008, 10:00:02 AM
Running a few numbers:

typical LED power dissipation: 100mA * 2V = 200mW
typical LED efficiency (SWAG): 50%
typical LED total radiated energy: 100mW

typical laser total radiated energy: 5mW

Looking at that it's not hard to figure out why people can't get the Wii Remote to see their lasers spots.

The Wii Remote doesn't need a really find point - just a smallish blob.  The right way to project one of these would be to take a high-current 940nm LED (like, say, an Osram SFH 4231 once digikey starts shipping them again) and put a collimating lens in front of it.  It'd be dangerous as hell >1W/cm², but it'd be equivalent to a very expensive IR laser for < $30.



Offline paolo2648

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Reply #23 on: March 07, 2008, 09:37:34 AM
Hey guys.  Interesting thread.  However - your kinda barking up the wrong tree here - it's been done with a laser already...

I know this is a forum for the Wii but why make life difficult.  Have a look here instead - http://graffitiresearchlab.com/?page_id=76  ;D

All the software is there to be found and it's all open source.  I've been using it quite a bit with a 30mW green laser (http://www.dealextreme.com/details.dx/sku.469) and it works really well.

I'm using a Macbook Pro with the Wiimote Whiteboard software and LOVING IT!  What I'd love to be able to do is use the LaserTag software as a 'mouse controller' - same a Wii Whiteboard software - allowing the use of other 'painting' software - Corel Paint etc.

I wouldn't have a clue where to begin doing this though - any ideas?

There's an interesting bit of camera software here - http://reactable.iua.upf.edu/?software - that you may find interesting...





Offline inio

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Reply #24 on: March 07, 2008, 10:29:57 AM
Sure it's been done with a laser - the point here is to make laser-like sources work with a different existing solution, and in better-lit environments.



Offline paolo2648

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Reply #25 on: March 08, 2008, 04:28:40 AM
"Sure it's been done with a laser - the point here is to make laser-like sources work with a different existing solution, and in better-lit environments."

I agree.  I thought this thread was about lasers though  ;D

When using the Reactable software with a laser you will notice that it picks up the dot quite well even in broad daylight.  If there was a way to adjust the brightness/contrast of the Wii camera or whiteboard software this would help loads.  Again, using some other software out there - touchib, lasertag etc - you can make these adjustments so all you see is the dot.  I'm not from a software background so wouldn't know where to begin doing this - I can only make suggestions...

The beauty of this Whiteboard software is that it can multi-track and be used to control other software easily - something the other's cant do 'out of the box'

There's another discussion on the forum that may help...

http://www.wiimoteproject.com/project-ideas/can-the-wiimote-be-modified-to-support-visible-light-t301.0.html
« Last Edit: March 08, 2008, 04:39:31 AM by paolo2648 »



Offline priegel

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Reply #26 on: March 09, 2008, 10:19:59 PM
I disagree on the calculation for IR laser light intensity. A 100mW IR LED with a 30 degree angle  will shine an appr. 5 cm2 dot at a 5 cm distance from the screen. This dot can be recognized by the Wiimote at 20 mW/cm2. When turning that LED towards the Wiimote, it is more easily picked up, with a spot size being the frontal area of the LED of approx. 0.2cm2. An IR laser would have to reach the 20 mW/cm2, but at a dot size of 0.2cm2. 5mW will do fine then. 2$ laserpointers come with those bits that create all kinds of shapes, there must be one that just increases the dot size. Or your Wii might pick-up an IR bunny...



Offline inio

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Reply #27 on: March 10, 2008, 01:50:17 AM
If you put collimating optics in front of a ~1W radiant IR LED, you could easily approach 1W/cm^2.  This is what would be needed if you want to be pointing at a screen from >10 feet away and detecting it from the same distance.



Offline sha

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Reply #28 on: March 12, 2008, 09:12:30 AM
Laser tracking? Yes, it is possible:

http://www.youtube.com/watch?v=WsvK7Euwa-I

Enjoy.



Offline paolo2648

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Reply #29 on: March 12, 2008, 06:31:02 PM
EXCELLENT!  I'm guessing thats a quite a low power laser you're using?  How far away can you get and still pick it up?  My Wii remote is stuck in the post!  Cant wait to get this sorted out  :D