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FrozenGate by Avery

IR Pointer Laser

Which is the best method for a safe IR pointer. 0.5-2cm spot at 15ft

  • IR Laser (low power)

    Votes: 12 80.0%

  • Green Laser (with no IR filter) (possibly unfocused)

    Votes: 2 13.3%

  • IR LED with optical lens for focusing (is this possible?)

    Votes: 1 6.7%
  • Total voters
    15
  • Poll closed .
B

Briago

0
Joined
May 25, 2009
Messages
4
Points
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I am trying to figure out what is the best device to use as an IR pointer laser.

Project: I am planning to try builing the WiiMote project for a IR controller white board. The project as the developer make it uses a standard IR LED at the end of the pen, which you hold to the screen. (The Wii part is that you use the IR camera in the remote to track the IR "spot".) (See: http://johnnylee.net/projects/wii/ for more info)

I would like to use a low power (I have no interest in burning anything) IR laser, or some lens focused LED, or perhaps a green laser with IR to point to the screen from a distance instead of right against the board.

What is the best option?:
1) Low power IR Laser (possible health risks)
2) Green laser pointer (may not be a focused IR point, I will need <2cm at 15ft)
3) LED with lens to focus the beam (unlikely to get the focused beam, and a lot of manual design to make happen if possible, though I am experimenting)

Goal:
From 15ft away, get a 0.5cm to 2cm dot reflecting from a projection screen to be detected by an IR camera.

Any thoughts?
 





Get yourself a 5mW or less 808nm pointer. That should be perfect :beer:

There are no more health risks from this laser than any other laser, other than the fact that you cant see it. Seeing as how it's low power, Its not a big deal. Even a 1 or 2mW 808 pointer would probably be perfect for what you need.

A green pointer wont work because the spot will be so far diverged at a distance it wont be very accurate at all, if it even works at all.
 
GooeyGus said:
Get yourself a 5mW or less 808nm pointer. That should be perfect :beer:

There are no more health risks from this laser than any other laser, other than the fact that you cant see it. Seeing as how it's low power, Its not a big deal. Even a 1 or 2mW 808 pointer would probably be perfect for what you need.

A green pointer wont work because the spot will be so far diverged at a distance it wont be very accurate at all, if it even works at all.
Click to expand...
Thanks for the tip, especially ruling out the green pointer.

As far as the 5mW or less, do you think it will be strong enough for a camera to see the spot reflection. The laser won't point at the camera, the camera will be looking at the laser spot reflection from the screen.
 
You could buy a cheap 5mW greenie from DX and take it apart and remove the crystals. Then using a video camera set for nightshot, to be able to see the IR spot, you can do your best to refocus it(difficult). After you get it columated you can use the pot to tune it down, and then back up until it just starts to lase. This would take some time and patience, especially re-columating IR. But it would be a lot cheaper than buying an IR pointer.

I have done this with a green laser pointer, except for tuning it down(pot mod)
 
lordoflasers said:
You could buy a cheap 5mW greenie from DX and take it apart and remove the crystals. Then using a video camera set for nightshot, to be able to see the IR spot, you can do your best to refocus it(difficult). After you get it columated you can use the pot to tune it down, and then back up until it just starts to lase. This would take some time and patience, especially re-columating IR. But it would be a lot cheaper than buying an IR pointer.

I have done this with a green laser pointer, except for tuning it down(pot mod)
Click to expand...

How would that be cheaper than buying an IR pointer? You can get an 808 diode in an aixiz module for barely more than a regular aixiz module.


As far as 'will the IR sensing camera see it', YES I think it will have no problem seeing the reflection. The one thing you might want to do is also include a 5mW 650nm laser, so you can actually see where you are pointing :)
 
Briago, hello, I too live in the Orlando area. I have some diodes from the PHR sleds that have IR + red in one(do some research). Do you have any axiz modules? If not I have several. I think this would work perfect for you. If you want we could setup a place to meet. Regards James.
 
GooeyGus said:
As far as 'will the IR sensing camera see it', YES I think it will have no problem seeing the reflection. The one thing you might want to do is also include a 5mW 650nm laser, so you can actually see where you are pointing :)
Click to expand...

Good point, also having two would be good as the red dot will show me where I am point at all times (constant on while in use), where as the IR will only be on "while clicking". As long as the IR dot is present it is like a left mouse click, so haveing the red as a guide would help even if the IR had a little visible spectrum (if it was a green laser).

I'm still looking for the 808nm lasers, so far I have mainly com accross 150mW modules for >$60. I'll keep looking. ... I may also try the green laser option as well since it is just a couple bucks. But I think I will target an 808nm 5mw laser once I find it.
 
There are no more health risks from this laser than any other laser, other than the fact that you cant see it. Seeing as how it's low power, Its not a big deal. Even a 1 or 2mW 808 pointer would probably be perfect for what you need.
Click to expand...

I second that. I don't trust 808 laser pointer, because your eye at this wavelenght, have no "blink reflex" : if your eye is receiving high powered reflexion, it won't close himself, he don't even know that he 's receiving this wavelenght, whereas your retina is burning (remenber that images are focalized on retina). Not the same story with more "visible" light like green, red or violet, when your eye detect a high powered light, your eye have reflex to close or your head to move away from beam.
 
Sorry, i guess i didn't think about 808 and 780 being pretty close and both showing up on an ir camera. This looks like the best solution, barring local options (Ramsey).

http://www.aixiz.com/shop/product_info.php?cPath=1_27&products_id=69


You have all been very helpful. For someone who doesn't have a lot of time (3 kids, one 2 WEEKS old). I have learned a lot quickly about lasers... I'm a EE so I don't expect an issue on the power driving side, but the optics and laser innerds are new to me.
 
Welcome Briago!

Just my two cents, (pennies where I come from!),

If you're feeling confident with the building of it I would seriously consider Ramsey_innovation's idea of using the IR diode from a PHR as they also include a nice, cherry red diode in the same can. This could kill two birds with one stone, (and it would be a pretty neat solution!).

I don't know if that 780nm IR Aixiz comes with a driver but I've used the red side of the PHR and am running it through a RKSTR driver at around 30mA.

... just a thought....

M
 
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mauswiesel said:
I second that. I don't trust 808 laser pointer, because your eye at this wavelenght, have no "blink reflex" : if your eye is receiving high powered reflexion, it won't close himself, he don't even know that he 's receiving this wavelenght, whereas your retina is burning (remenber that images are focalized on retina). Not the same story with more "visible" light like green, red or violet, when your eye detect a high powered light, your eye have reflex to close or your head to move away from beam.
Click to expand...

it's going to be like 3mW.... It's not a big deal. As long as he knows not to point it toward himself or others, just like any other laser, he'll be fine.

People freak out so much when it comes to near IR... 1mW of 808, even if it was directly into your eye, is probably not any more near IR than you would get standing out in the sun on a bright day.

Just be mindful, like any other laser, and you have absolutely nothing to worry about.

People seem to freak out more about a less than 5mW near IR laser than they do about a 100mW 532. Just because you can see the green doesn't mean accidents don't happen.
 
It sounds like you are going to do something similar to what I want to do - use the dot from the IR laser with a wii remote to control a pc (with a MythTV OS)

At least that's the plan, and I figure that a couple of low power IR lasers would be a good first project before I try a high power blu-ray laser. :P
 
If your pointing it a the screen can't the Wii draw a cursor for you? Either way the PHR diode does sound like a good idea.

Edit: Oh I understand now, yah knowing where your pointing is a good idea.


Jon
 
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