Hi guys

I saw that you guys know a lot over touchscreens and what to look for
ok ...
I was thinking about making a touchscreen out of a plexiglas screen of an old flatscreen monitor about 17”
I thought at doing the FTIR methode, because that seemed pretty aweseome and interesting.
But now i dont know what type of IR-LEDs I should use :-\
I don’t know for what i have to look out :-(
I know the LED should have over 50mW intensity right?

OK ... I looked a little bit around and found following LEDs (actually i thought i need to have a very acute shine degree)
1) LD 274-3 (5mm, 10°, 950nm, >80mW/sr)
2) SFH 485 (5mm, 20°, 880nm, >25mW/sr)
3) SFH 485 P (5mm, 40°, 880nm, >3.15mW/sc)
4) SFH 415 (5mm, 17°, 950 nm, >25mW/sc)

Is one of those a LED i should use?
or are they all bad for my setting?
I also thought if it is not a good idea to combine a acute and a wide angle LED?
actually it would have to “reflect” everywhere or doesn’t it?
And if i have a acute angle LED does they work close to the edge, because the java applet showed me that there is a small distance till the light reflect up to the edges

I hope you can help me =)

and if that weren’t still enough questions here are some more:

1) should i put some silikon on the top of the plexiglas?
2) Does tracing paper work as a difuser?
3) for what do i need the “2nd” acryl/plexiglas piece? just to hold the paper? can i use some plastic instead (because i wasn’t planning on spending too much money and acryl is expensive here in germany)

Hope that are not too much questions =)
I hope to see a quick answer

Best wishes from Germany,
Splash_5