FreeTrack Forum

Hi!

my fisrt attempt of building a pointmodel (3 LED Headset clip) ended with a good and solid model but not so good (not ideal viewing angle) LED's

the only suitable led's i found in the local store where:

1,5v Fv
65 mA
unknown viewing angle

this LED's (powered through USB 5v (actually 4,98v) and a 65Ohm resistor only 5% (one for each led) - so i'm not sure that im getting 65mA .. maybe something more like 55-60mA) are not the brightest (but bright enough if i do not apply any filter in front of the camera (i had a magnetic disc of an old floppy disk in front of the cam to block all the "normal" light and let only the IR light through)..
they even have another problem .. they have a very narrow viewing angle and the webcam cant see their light if they are pointed to the side..

i actually tryed to cut the top lens of the led (and have a flat surface instead of it) but i wasted 2 LED's because that didn't work .. the light power emitted was way too low because of the opaque surface (even sanded with fine paper)

so i tryed sanding only the side of the led's and it actually helped a lot (LET THE TOP OF THE LENS UN-SANDED!)

now i can rotate my head a little but it's still not enough even with high sensivity set on yaw axis..


so i ordered new led's online and they will have:

1,5v - 3v Fv (will use something about 2,5v)
100mA
160° viewing angle (written on spec's but i'm sceptic)

using high precise 1% 30Ohm resistors

if this will work good i'm happy .. if it's still to low viewing angle and the webcam can't recognize it good when head is turned i will change following:

instead of 3 LED's i will use 9 - yes 9 - LED's .. 3 big points made of 3 led's each ..


in front of all three points i will apply a semicircular disc of white transparent plastic (will use a ping pong ball cutted in pieces) .. the power of three led's for each point will be enough to pass trough the opaque plastic and the plastic will act as a light diffuser so the point will be recognised nearly 180°

i will post here next week with the new pictures .. i think the last "version" using ping pong balls would be the best pointmodel .. it would be very precise, efficient and powerful


bye!

The best buy for SFH485P:

http://www.seeedstudio.com/depot/original-osram-ir-led-sfh485p-10-pcs-pack-p-69.html?cPath=28

Pack of 10. Cheap and quick delivery. I have them.

tracker @ 11/12/2010 - 14h45 a dit:

The best buy for SFH485P:

http://www.seeedstudio.com/depot/original-osram-ir-led-sfh485p-10-pcs-pack-p-69.html?cPath=28

Pack of 10. Cheap and quick delivery. I have them.

thanks for the link ... but ... ehhhmmm .... i live in italy    

i dont think 5$ of LED's are worth 49$ of shipping  

i already ordered the SFH485P on farnell-italy .. payed 3€ for 5 of them (about 4$)

;-) i'm on holyday in austria the next week .. so can't build the pointmodel before next saturday .. but will post by the end of next week with updates

I paid 7,58$ (5,74€) with P&P and I live in Slovakia.

Farnell in my country has big P&P.   Nevermind, you will have them now...

tracker @ 12/12/2010 - 11h15 a dit:

I paid 7,58$ (5,74€) with P&P and I live in Slovakia.

Farnell in my country has big P&P.   Nevermind, you will have them now...

yes, this because farnell has different stores for each state .. so i ordered at farnell-italy .. the problem is that they blocked and erased my order because here in italy you have to be a re-seller or a factory to order by farnell .. they doesn't sell anything to "normal" people ..

so i ended ordering at "www.led-eshop.de" paid 12€ for 10 LED's and shipping..

hope they arrive soon ..