Wiimote Project

Hardware Support => IR Pens => Topic started by: dice on September 22, 2008, 02:49:17 PM

Title: How well does diffusing the LED work?
Post by: dice on September 22, 2008, 02:49:17 PM
Hey Everyone,

I am going to be starting to create a new light pen and I have been looking at some techniques that different people use with LED's and I found this one that seems promising.

Diffuse The LEDs (http://www.instructables.com/id/SZZ6TWUFCEIOGPV/)

before
(http://www.givepix.com/out.php?t=33_F5OV8KCFCEIOGG3.MEDIUM.jpg) (http://www.givepix.com/out.php?i=33_F5OV8KCFCEIOGG3.MEDIUM.jpg)
after
(http://www.givepix.com/out.php?t=32_FBSYVH3FCEIOGG2.MEDIUM.jpg) (http://www.givepix.com/out.php?i=32_FBSYVH3FCEIOGG2.MEDIUM.jpg)

What do you all think about this, or what do you use?

Thanks for the help
Dice :)

It looks like the guy just used normal sandpaper, looks like a fine sandpaper.
Title: Re: How well does diffusing the LED work?
Post by: benpaddlejones on September 22, 2008, 04:37:42 PM
Dice
Be interesting to compare to the silicon and foil methods I have heard about, sandpaper certainly looks good.

Benpaddlejones :)
Title: Re: How well does diffusing the LED work?
Post by: dice on September 22, 2008, 04:39:00 PM
I have also seen people using Hot glue to do it.. Im going to try a couple different things over this next week and take some pictures and see what you all think.

Dice :)
Title: Re: How well does diffusing the LED work?
Post by: Smokeduv on September 23, 2008, 10:57:32 AM
well, it works in a way, the problem starts when you diffuse the light because you have to get a opaque finish that will affect the light intensity, so, if you have a very good LED, you cn give it a try, I have tried with hot glue, sandpaper and some matte finish spray being the spray the faster but the one with very different results every time due to the quantity of paint. Hot glue seems to be the better for me because it doesn't damages the LED and also, depending on the cooling time or the temperature on the glue it gives a cristal clear finish or a non-clear finish I don't know exactly why, but give it a try and share your comments.
Title: Re: How well does diffusing the LED work?
Post by: dice on September 23, 2008, 01:16:04 PM
I didnt see your results with the sandpaper... am I missing it, I see that you say the Glue would be better. My thinking if is if you got a ultra fine sandpaper, like a car paint stand paper, something like a 1000 grit.  I would think it would be just enough to make it diffused without making limiting the light to much.  I just bought some cheap LEDs so Im going to try it out and see what it looks like with them.

Dice :)
Title: Re: How well does diffusing the LED work?
Post by: JoriQ on September 24, 2008, 09:03:43 PM
Would be great to get testimony of how this changes the functionality of the pen. Does it drastically improve performance?
Title: Re: How well does diffusing the LED work?
Post by: Smokeduv on September 29, 2008, 04:31:19 PM
Joriq, well, unfortunately i gave my IR pen to a school, they needed one to replace the one they were using (expensive and battery-sucking one), so, i don't have it right now to show you, but i can tell you that i had to show them it was better than the other one, and they were convinced, it worked great, it was made with hot glue for the diffusing thing, the bad thing is that i lose some light intensity, but it is very accurate because now it works with the diffused light, not the reflection in the board. Another strange thing, it would want to say that diffusing light is the best, but unfortunately it doesn't works as good as with visible light LEDs, i don't know why, but it doesn't lights up all the glue, or led if you use sandpaper as with any other LED, maybe it is because of the LED not being as powerful or what. Anyway, try it for yourself and share your results. It worked for me (although not as good as I wanted, but it worked).
Title: Re: How well does diffusing the LED work?
Post by: bubka on October 19, 2008, 10:47:36 AM
I would think that the reflection off of the board would be picked up as a single dot from the wiimote, so it would be to your advantage to have as much going back as possible, regardless if it is from the IR or board reflection.

It would be nice to see some field testing, although I have no problem with my pens as is.
Title: Re: How well does diffusing the LED work?
Post by: rylangrayston on October 19, 2008, 04:19:35 PM
If you were to use an infer red laser pointer you would be free to move away from the screen as well as touch it!

this method would get be very shaky at 30 feet but
would work great at 10 or less which is far enuf to stop casting a shadow and or blocking someone else's view.
Title: Re: How well does diffusing the LED work?
Post by: Hoaxjak on February 09, 2009, 02:32:26 PM
i've been following this as well

they DO make LED diffusers, i have never seen or touched one however so i have no idea how it performs compared to say; sanding or hot glue


an easy test would be to get several identical LEDs, expose them to different diffusion methods, line them up and take a picture so see which ones are brightest at different angles.