FreeTrack Forum

Has anyone ever attempted to use 10mm IR LED's rather than 5mm.

The reason I ask is that with my Camera (M$ VX3000) I always have to go in to the M$ camera settings and increase the zoom level every time I use FreeTrack.  Therefore I was considering using 10mm LEDs as an alternative but not sure whether this would be a good idiea or not.

Anyone want to comment.

Hi Tron

I should say, have a try, if it's not too expensive. But it depends on brightness and beam angle of them, more then size.
But couldn't you simply use the threshold slider to make the Ø5mm more visible?

Use Fimo to enlarge the size of your leds!



Read this topic:

http://forum.free-track.net/index.php?showtopic=2378#13648

Thanks guys for your replies.

I have actually got around the problem by purchasing an PS3 Eye and removed the IR  Filter   , but ...

because I was interested with the Fimo balls mod it was that, that gave me the idea of using 10mm LED's.

The 10mm IR LEDs @ 850nm appear very compatible so I have ordered them to set up a prototype rig to see if it makes any difference.

To give you some idea they have a 40deg viewing angle @1.4v with radiant intensity ranging from 6mW/Sr @ 20mA to 30mW/Sr @ 100ma.  Now the SFH485P spec is min 3.15 - max 5.5mW/Sr full out at 100mA so the 10mm dia LED are brighter at a much lower current rating.  Whether or not that will create too much bloom is yet to see.

The SFH48P are at 880nm but unless you are going to purchase band filters to install inside the camera then the difference between the 850 & 880 is negligible. As most of us use floppy disk media I won't go in to this now.

I did consider using 10mm 940nm LED's but these only have a 30deg viewing angle.

Once the 10mm LED's turn up I wil build the prototype and report back here my findings/observations.

@Steph - yep you are quite right about increasing the software threshold but then that introduces more background noise (ambient light) even with the floppy disk media in place.  The idea here of course is to get the best you can but still keeping it cheap.

To give you some idea they have a 40deg viewing angle @1.4v with radiant intensity ranging from 6mW/Sr @ 20mA to 30mW/Sr @ 100ma.  Now the SFH485P spec is min 3.15 - max 5.5mW/Sr full out at 100mA so the 10mm dia LED are brighter at a much lower current rating.  Whether or not that will create too much bloom is yet to see.

That sounds good. Waiting for the results.

...but then that introduces more background noise (ambient light) even with the floppy disk media in place.

I know that. Using an unmodified cam, I spend a lot of time to find out the best way to filter daylight and finished up with a ir-filter from an ir-receiver-module. I found this little piece of dark plastic behind the display off an old video-recorder with ir-command. Since that, no more problem with any other light-source.