Wiimote Project

Hardware Support => IR Pens => Topic started by: gabort on January 09, 2008, 08:36:05 PM

Title: The birth of "Big Motha"...
Post by: gabort on January 09, 2008, 08:36:05 PM
I've been struggling with getting the wiimote to sense my puny 20mA leds, so I did lots of research to find some more powerful components today.

We don't have Radioshack here, in fact I am sure that a lot of places lack a Radio Shack, so here's what I found.

I bought two types of IR leds, both are 100mA, so pack a pretty good punch.

Siemens makes one, called the LD 271 (link:http://www.ortodoxism.ro/datasheets/siemens/LD271HL.pdf (http://www.ortodoxism.ro/datasheets/siemens/LD271HL.pdf) to specification .pdf)
And I also found another one called the CQY99, probably Phillips... http://www.hqvideo.hu/info/en/cqy99.html

It still seemed to me, that the wiimote has difficulty catching the light from a single led, although I had a nice marker set up to go, and I switched the led to one of the bigger ones.
(http://kepfeltoltes.hu/thumb/080110/small_wii_pen_www.kepfeltoltes.hu_.jpg)

I decided to change all that, and to get rid of the "performance bottleneck" once and for all. I wired 3 of the new 100mA leds together in series soldering them together, so that they would form a nice point with three leds together.
(http://kepfeltoltes.hu/thumb/080110/3_IR_LEDS_www.kepfeltoltes.hu_.jpg)
To avoid short circuiting, and to add stability to the point, I filled the space between the solders, the tip of the pen, and around the leds on the outside with hot glue.
(http://kepfeltoltes.hu/thumb/080110/3_IR_WITH_HOT_GLUE_www.kepfeltoltes.hu_.jpg)
The setup needs 4.5 volts. I use an adapter, but three batteries will do the trick as well. Needless to say, the Wiimote finally tracks this with ease. It is probably a good solution if you have a big projection screen, and need to put the Wiimote way back too.

So behold: Big Motha :)
(http://kepfeltoltes.hu/thumb/080110/BIG_MOTHA_www.kepfeltoltes.hu_.jpg)
Title: Re: The birth of "Big Motha"...
Post by: dice on January 09, 2008, 11:41:53 PM
Great Guide! this is what this forums is all about, very happy to see this guide so early in this sites history.

Thanks
Dice :)
Title: Re: The birth of "Big Motha"...
Post by: bryanarby on January 11, 2008, 12:48:30 AM
*gunk :o, falls of his chair seeing how cool 3 LEDs looked*
Btw you might make a cap around the LEDs to make the IR light only go straight (more accuaracy<-I don't know how to write that lol).

anyways im working on one aswell, i'll post some pictures when it's done (today at evening I guess...) oh and ill test it BEFORE posting it, if it doesn't work well ill have to remod my pen xD

Greetz,
Bryanarby
Title: Re: The birth of "Big Motha"...
Post by: holyone2 on January 27, 2008, 08:05:37 AM
Would this not loose some resolution, as opposed to a singlular 'super-bright' LED?
Title: Re: The birth of "Big Motha"...
Post by: tucker on April 15, 2008, 09:50:58 PM
I am currently completing my 3 LED pen, with 3 AAA batteries.  The question that I have is: are any resistors needed to reduce the current flow?  I am new to electronics and would appreciate any help.  I am using the VISHAY TSAL 6400's.  While it is currently is working, I am afraid that the LED's may fry with frequent use.  Thanks
Title: Re: The birth of "Big Motha"...
Post by: UndCon on April 16, 2008, 12:23:23 AM
I can recommend this site - www.ledcalculator.net
Title: Re: The birth of "Big Motha"...
Post by: tucker on April 16, 2008, 05:36:02 AM
I have tried this website but the schematic does not match my design.  I have the 3 LED's in series.  Also, I am assuming the voltage of the LED is 1.6 volts and the current is the forward current (100mA) and not the peak forward current (200mA).  Again, I am new to electronics and am unsure if I am putting in the right information.  Thanks for any assistance. 
Title: Re: The birth of "Big Motha"...
Post by: UndCon on April 16, 2008, 06:25:47 AM
If you search google for led calculator you get several hits

including this one that might do the trick in your case
http://www.hebeiltd.com.cn/?p=zz.led.resistor.calculator

many pages also have instructions how to calculate...
Title: Re: The birth of "Big Motha"...
Post by: imarzouka on April 17, 2008, 09:01:07 AM
hi tucker, the reason ledcalculator.net is giving you 2 LEDs in series with 1 LED in parallel is because your source voltage is not high enough to run all LEDs in series. Your source voltage = 3 x 1.5V = 4.5V and your LED voltage drop is 1.6V x 3 = 4.8V which is more than 4.5V. So if you need to run them all in series, you need to add another battery 1.5V so that your source voltage will be 6V.

Iyad Marzouka
http://ledcalculator.net
Title: Re: The birth of "Big Motha"...
Post by: tucker on April 17, 2008, 06:19:23 PM
thanks for the great reply.  What would you suggest.  Should I run them in series, or parellel and have resistors?  Is there any disadvantage to not supplying the LEDs at full voltage.  Also, it was my understanding that it was the current that would burn them out not the voltage.  I have tested the 3 LED setup (with 3 AAA) and it seems to work better, than the single LED with a 30 ohm resistor.  I would appreciate any suggestions or advice.  The setup I am using is an LCD projector with the wiimote 6-7 feet away.  Thanks again.
Title: Re: The birth of "Big Motha"...
Post by: imarzouka on April 18, 2008, 12:59:27 AM
well.. if you want to get the maximum performance of your LEDs I suggest you use both the series/parallel configuration as the calculator says. They will also live longer. If you supply a LED with less voltage that its typical voltage, it wont light at its full capacity. And sometimes it might not light at all if the voltage goes below a certain threashold.

And remember, you always need to use a resistor to limit the current. In your case with 3xAAA batteries and 3x1.5V LEDs, you should at least add a 1ohm resistor. That is because the LEDs do not have internal resistance like resistors. And this way they will live longer and consume less power from your batteries.

Iyad Marzouka
http://ledcalculator.net