FreeTrack Forum

Hello there guys

i wanted to share an experience that happend to me while building my freetrack point model...

I was using 4 x 200ohms 2W resistors in parallel paired with three NTE3027 IR Leds (940nm, Vf 1.85v, If 150mA max, 45°) in serial connection... as power supply i was using a 9v square battery... i was building a 3 point clip with the following meassures (Aprox)
60
    67
    81
80

This configuration works with my Wii Remote but sometimes the points start blinking and the tracking become unstable, so i decided to try with a normal webcam without ir filter... I found that with the web cam the tracking is a bit more smoother than with Wii remote but the point when using the webcam are bigger than when using Wii Remote and sometimes the point get so close that one is missed... so i think Wiimote has some sort of auto focus or something (and yes, I tried to get the webcam focused)

Then I decided to tune my point model using Handbook suggested meassures
30
   40
    70
80

but this time i used a 15v/1A regulated power supply to push my IR led nearest to its max capabilities Vf1.85, If 150mA... according to led assembly wizard for 15v power supply, 1.85v for every led and 150mA as assembly current the theorical value is 63ohms (nearest available upper value is 68ohms), so instead of 4 resistor i used 3 x 200ohms in parallel for a combined resistor 0f about 66,68ohms...  the result using the Wiimote was the oppositive to that what i was specting: The point aren´t bigger and instead they were blinking in freetrack no matter what threshold value i use, I even tried modifying "Average" vaue that appears in the advanced section of profile tab but no luck at all...

Then i remenber that somewhere in this forum I read that the Wiimote is very sensible and can become satured easily... so my third step was to reduce forward current back to 100mA, I needed to remove one resistor and let only two in the assembly but that didn´t make any difference with the blinking points

BTW i also tried using the webcam while powering my point model with the regulated power supply in both cases there was not blink at all in free-track

At last I´m back using battery power in my wiimote, but tonight i will be conducting some other test this time with two diferent power supplies 9v and 7,5... I will let you know in case you are interested

Regards

Test results... it´s seen like my IR Leds don´t like to be use with AC to DC adaptors... I´ve tried two different adapters (9V/1A and 9V/210mA) and the result is the same: Blinking IR Leds no matter if i use wiimote or webcam

My IR Leds (NTE3027) are cataloged as High Speed, so this could be the source of my issue, now I think the IR leds are blinking because the adapter´s output isn´t regulated enough.

As i mention before, using a 9v Battery doesn't cause the blinking

My next step will be to try to stabilize the output using some capacitor or voltage regulator

fzfq3m @ 10/07/2009 - 14h28 a dit:

Test results... it´s seen like my IR Leds don´t like to be use with AC to DC adaptors... I´ve tried two different adapters (9V/1A and 9V/210mA) and the result is the same: Blinking IR Leds no matter if i use wiimote or webcam

My IR Leds (NTE3027) are cataloged as High Speed, so this could be the source of my issue, now I think the IR leds are blinking because the adapter´s output isn´t regulated enough.

As i mention before, using a 9v Battery doesn't cause the blinking

My next step will be to try to stabilize the output using some capacitor or voltage regulator

Yep it seems that the AC->DC adapter isn't working ok...

Yep,... a Third AC/DC Adapter did the trick... working stable right now.. time for more tunnig