Wiimote Project

Hardware Support => IR Pens => Topic started by: xxvi on October 10, 2008, 05:54:34 PM

Title: Light Difraction problem
Post by: xxvi on October 10, 2008, 05:54:34 PM
I had some problems working with ir pens, it happends in all the e-whiteboard programs, so its more a hradware problem that software. The thing is that appears 2 or even 3 dots from one same ir pen:
1. The real emisor diode
2. The reflection that happens in the capsule of the diode
3. The reflection that happens in the LCD of the computer or surface projected.

Im working to avoid this, because this effect make problems in the recong of IR signals by de wii, and makes that the pointer (in like an example) moves crazy in several directios or appears an offset of the point that you want to select and the mouse pointer selection.

If some one have a suggestion about how to solve this i really thank you to say me.
Title: Re: Light Difraction problem
Post by: benpaddlejones on October 10, 2008, 06:16:43 PM
xxvi
Normally the diode, case and reflection if your IR-Pen is touching the surface is identified as a single IR-Blob.

Potential causes:
- Sunlight
- Reflected sunlight
- Other IR Source
- Highly reflective surface

Diagnostics
1. Try running everything at night, will eliminate sunlight factor
2. Turn all lights off, use a mobile phone camera (most are IR-sensitive) see if you can see any other IR-sources
3. Run jasonlpsmiths Presenter application, at the bottom of the screen is a visual representation of the IR-Blobs detected and their strength (red = strong & Blue = Week, don't quote me may be the other way around).

Let me know how you go.

Goodluck

benpaddlejones :)
 
Title: Re: Light Difraction problem
Post by: Torden on October 27, 2008, 06:22:36 PM
Check out my post solving this problem:

http://www.wiimoteproject.com/ir-pens/simple-and-efficient-enhancement-of-the-ir-arch-of-emission/ (http://www.wiimoteproject.com/ir-pens/simple-and-efficient-enhancement-of-the-ir-arch-of-emission/)