FreeTrack Forum

OKay, so I am using IR emmitters from some old remotes. First off, the camera can see them, but I need to find out the Voltage specs on them, any ideas? I cant wire anything to it until I find it out. I dont want to ruin them so early in the project.

Im also using an older logitec quickcam express, Im not sure how old they say these things can be but I read that there are issues using older versions. Anyways, I also need a link to the "enable button" to turn off auto exposure since I cant find it anywhere. My fps right now is at 15. If I cant fix that Ill probably buy a new webcam thats known to work well, but im on a tight budget for this basement science experement...

Im using a 9v battery as the power supply and I need to know what value of resistors I need for the reason stated above.

I am also considdering starting from scratch with a bicycle light like I saw several 3 poin ones in the gallery had done. Is this a better plan since I am not that talented at electrical stuff? Thanks for the Input on any of this.

Aries_69th_vfw @ 03/04/2008 - 07h37 a dit:

Im using a 9v battery as the power supply and I need to know what value of resistors I need for the reason stated above.

Freetrack build model doesn't requier any "talented at electrical stuff" ...
It's very easy to build !

First one go here to find best model build and resistors value :
http://www.free-track.net/english/hardware/calcled/

and go here to see some examples :
http://www.free-track.net/english/hardware/point_model_gallery.php

For model dimensions, go in freetrack software and look model dimension given by freetrack software !

Hello Aries

The problem is you usually don't know your led characteristics, when you salvage them from remotes.

So you'll have to "guess" :

1)
there's no way to know the operating current of your led, even by looking at the remote diagram (unless the led reference is written on the PCB)
(because with freetrack, our leds work in continuous mode as opposite to remotes , in which they operate in pulse mode).

So we'll have to use a "standard value" of about 20mA.

Normally,  every Led accepts at least that value.

2)
IR led often have a 1.2 to 1.5 v forward voltage

3) to find the correct forward voltage of your led, you have to make a 1st setup, to calculate your led voltage drop, then a perhaps a 2nd and final setup.

4) 1st setup :

Only use 1 led. If your leds come from different remotes, you'll have to check each led on its own.

Try with the following values :

Power supply : 9v battery
Number of leds : 1
Led foward voltage : 1.5V
Led operating current : 20 mA

Use the led wizard to get the appropriate resistor.

Once this setup is powered on , use a multimeter or a voltage tester to get the real led forward voltage.

5) 2nd setup :

Add the led forward voltage of all your leds, you'll get a "global led voltage drop" value.

Use the wizard :
Power supply : 9v battery
Number of leds : 1
Led foward voltage : your "global led voltage drop"
Led operating current : 20 mA

6)
use this resistor value on a serial type setup.

(you can get the schematics by using the wizard with the values : 9v battery / 3 leds / 1.5v forward voltage / 20ma forward current)

That should do the trick.

Cya.

I used 9V battery as my soiurce for a while, it is ok but, it gets wasted a bit fast (2-3 weeks max), so I tried to use a 8.4v accumulator that can be recharged... the results were worse than anticipated. The 8.4v accu has just 170mAh so is quite weak. Now I switched to 4XAAA accumulators that have each 850mAh (you can find with 1000mAh). Those are working for 2 weeks before I need to recharge. The weight is a bit bigger but not much.

They look like this (the batteries inside are just for the picture):



and here a small scale production for some squadmates: