I know that green laserpointers are producing infrared light.
The expensive ones have filters but the cheap ones do not have good filters. Therfor you can try a cheap green laser pointer. The poweroutput does not have to be very high.

I was looking at components, and they sell some that only do 5mA. I'll ask around first though, because I know they could be dangerous. A 100mA led is ok, because it radiates it's power at 30 degrees, so the density of the light is much lower. Something that concentrates nearly all its power in a tiny dot provides light that is far more dense, even if its overall power is less than that of the led.

I found things like this:http://www.worldstartech.com/products-ldm_uhl_series

But it's hard to miss this, at the end of the specification sheets...

yes but constructing the pen is half the fun.

hmm... but changing and compiling the code is half the fun to...

ok so maybe its just a third the fun so you can actually have fun with the app.

Let me get this very straight: You used an IR laser?
OR was it a normal LED based pen that worked 3 feet from the screen?

Pls. go into a little more detail. thx.

No offense, but I have my doubt on the accuracy of that setup. If you tilt the pen, the laser will show at a different spot on screen, yet there will be no precievable change from the Wiimote's point of view.

Also, to my own question: Here is a classification of what lasers may yet be safe.
http://ptcl.chem.ox.ac.uk/MSDS/laser_classification.html

I also found a chart on another site, and inserted a red line into the approximate wavelength the Wiimote senses. It does not look very good, we really need to be careful with an IR laser.


Source: http://www.asu.edu/radiationsafety/laser

For a first experiment, I want to try a real low power device.

Today I orderd an IR laser pointer from Vienna. It is supposed to be eye safe, and cost me about 40 EUR.

I can't wait to try it out. I'll let you know, if it works, when I get it.

RLT-302UC, 980 nm, < 40 mW, 3 x LR44, eye safe operation

Well, it does not seem that IR lasers can be used effectively.

The model I was hoping to get was no longer in stock, but a laser module with essentially the same specs let me carry out the experiment, none the less.



Here's how it ended up looking, when I assembled it into an old pen:



It has a nice focusable end to it, so that's not why it essentially failed.



The Wiimote is completely oblivious to the beam. The only time it takes notice, is if you shine it right into the camera... I tried all sorts of surfaces - shiny, dark, smooth, rough - NOTHING.

I suspect that the beam was simply not strong enough (the wavelength was spot on).

I used a 2mW laser. Now a 20mA (amp, not watt) led in my first led-based pen that was too weak for my taste is essentially a 3mW output at 1.5V. So 2mW might not be enough. A 100mA led that works fine is 15mW output at 1.5V. So that might explain it... on the other hand, I was just not willing to risk damaging my eyesight with something more powerful.

Cost is also a factor. If you look at some of the more powerful laser modules, 20mW and above, its well over 150EUR, which is out of range for such low budget simple solutions. Also, the beam might be powerful enough to blind you, or someone else.

So, while this is not the answer I was hoping for, I think we can declare IR laser based solutions with the Wiimote a flunk.