Wiimote Project

Hardware Support => IR Pens => Topic started by: benpaddlejones on May 12, 2008, 05:07:32 AM

Title: What is the Wiimote's Preferred Peak Wavelength???
Post by: benpaddlejones on May 12, 2008, 05:07:32 AM
Wiimote Friends

A couple of posts have suggested that the Wiimote has a prefferred Peak Wavelength.

If so does anyone know what it is ???

benpaddlejones
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: inio on May 12, 2008, 11:04:10 AM
Off the top of my head, I believe it to be 850.  IIRC the sensor starts falling off past that, and the filter (black window) in the Wii Remote starts blocking below that.
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: inio on May 15, 2008, 11:36:40 AM
Off the top of my head, I was wrong.

To determine the relative sensitivity of the Wii Remote, two leds with similar characteristics were used: SFH4231 (940nm, 180mW TRP @ 1A) and SFH4230 (850nm, 200mW TRP @ 1A).  Both devices provide an approximately Lambertian distribution of light, with a 1A maximum continuous current and 1.8V drop.

The LEDs were attached in series with a laboratory power supply, 5-digit ammeter, and 0.5-ohm resistor.  The LEDs were positioned vertically approximately 30cm apart, facing a Wii Remote approximately 5m away.  Measurements were taken with camera gain values between 0x10 to 0x40 and minimum blob size of 3.  For each configuration, the minimum current at which each LED became visible was recoded.  Gain values higher than 0x40 resulted in the 850nm LED being undetectable even at 1A.

Without filter window in place: The 940nm LED was detectable with approximately 12% the current required to detect the 850nm LED.

With filter window in place: The 940nm LED was detectable with approximately 15% the current required to detect the 850nm LED.

Executive summary:  The Wii Remote is at least 5 times more sensitive to 940nm than 850nm.
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: inio on May 24, 2008, 10:05:32 PM
Whops, part number in the above post were wrong.  Fixed now.
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: benpaddlejones on May 24, 2008, 11:16:05 PM
Thankyou

I tried a 80 degree viewing angle 100ma IR-LED it was terrible, very irratic tracking. Its wave length was 880nm, that was the only varience other than the Viewing Angle from the Vishay TSAL6400.

Will add to my knowledgebase  ;).

Benpaddlejones
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: micbridge on May 25, 2008, 09:56:36 AM
I appreciate the test of wavelengths inio. I can't say I have lab tested the wavelength pickup of the wiimote.

I can say that the 850 nm wavelength of the side-mounted LED's I've used work great even in the very bright lighting of our office conference room out to 19 feet.

So I wouldn't go so far as to say that 950 nm is the preferred wavelength for LED's. I will say that I wish I had a best practices guide like the one you just posted when I started this wiimote project a couple months ago.
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: Francisco on May 25, 2008, 01:34:56 PM
Inio,
Thanks for your clarification!
My new pen (with the Vishay TSAL 5300 led) have precisely this Wavelength.
http://clinik.net/wiimote/wiimote_info_my_pen_2.php (http://clinik.net/wiimote/wiimote_info_my_pen_2.php)

For those who can't find the TSAL 6400... the TSAL 5300 could be a possibility.
Thanks
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: Gavin on March 15, 2009, 10:32:19 PM
Just an update on TSAL5300 v.s. TSAL6400.

The 5300 actually has cleaner lensing than the 6400, so though it's only +-22 deg
v.s. the 6400 +/-25 deg, the 5300 will give more even illumination.

Look at Fig. 9 - Relative Radiant Intensity vs. Angular Displacement
here:  http://www.vishay.com/docs/81011/tsal6400.pdf
v.s Fig. 9 for the 5300
http://www.vishay.com/docs/81008/tsal5300.pdf

As far as intensity goes, the 6400 specs min typ max at  25 40 125 mW/sr
while the 5300 is  30 45 150
They are both 940 +/-50 nm so same wavelength

I think the TSAL5300 is actually a newer as well as a better part than the TSAL6400

G
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: Francisco on March 16, 2009, 07:07:11 AM
Hi Gavin,

I'm the TSAL5300 guy :) just because my local store didn't have the 6400.
We search in big catalog some identical IR Led and found the 5300.

Undcon send me some 6400 IR Leds and I made this home test (with Arduino, my new toy ;) ):
http://www.wiimoteproject.com/ir-pens/electronics-101-sharing-my-mistakes!-***-updated-***/msg8368/#msg8368 (http://www.wiimoteproject.com/ir-pens/electronics-101-sharing-my-mistakes!-***-updated-***/msg8368/#msg8368)

Almost a year ago (May 21, 2008) I made this question:
"Can we say that TSAL 5300 is better than TSAL 6400?
Have we a 'new' winning IR led?"

I can't tell you witch is the best IR Led but I think it's fair to say they are both good IR Leds for Wiimote Whiteboard.

Cheers
Francisco
Title: Re: What is the Wiimote's Preferred Peak Wavelength???
Post by: benpaddlejones on March 16, 2009, 08:05:51 PM
Francisco/Gavin
The TSAL5300 is slighly better if not diffused. (TSAL6400 is more available internationally). But as soon as you diffuse they are no different.

Nothing to do with being a newer product just an intentional manufacturing variation.

As Francisco said they are both perfect for the Whiteboard.

benpaddlejones :)