FreeTrack Forum

So I have decided to go ahead and get the radioshack LED's and cut the tops off for better wide angle performance.

  Link for specific one-

 http://www.radioshack.com/product/index.jsp?productId=2062565

 and I plan to power it with a 5.3 volt nokia phone charger with the following information on the casing.

  AC-2U - input 100V - 200V
  50 to 60 hz/ 150ma
  output 5.3V=/500ma

 I put all the information into the build calculator that is linked on the sidebar on the main freetrack page with the following inputs.

 setup type - 3 LED's
 power supply voltage value - 5.3
 power supply family - unregulated power source
 LED forward voltage - 1.28V
 LED forward current - 100ma

 I was then presented with a very confusing diagram that told me this.

 POWER SUPPLY    Power supply (V)    5.3 V
!! Attention :

These unregulated power supplies usually provide a higher voltage than indicated (about 30%).
Power supply voltage adjusted for processing : +30% => 6.9 V
LED    Led forward voltage (V - manufacturer info)    1.28 V
Led forward current (mA - manufacturer info)    100 mA
LED ASSEMBLY     S : serial assembly
RESISTOR COUNT    1 resistor(s) needed for the complete kit
RESISTOR THEORICAL VALUE    30.5 Ohms
RESISTOR CHOICE E24 SERIES    Resistor value    33 Ohms 5%

Current    92.4 mA
Dissipated power    0.28 Watts
Total current in assembly    92.4 mA


 so when I go to radio shack tomarrow to pick all this stuff up, what resistor should I buy? I cannot seem to find a specific "E24" series so could I just take these results to the store and ask for the best choice?

 perhaps someone could look on the (U.S.) radioshack website and post a link to a specific model.

 now the next part.

 I have removed the small plug at the end of the AC adapter and it revealed two wires with no color code or anything, they are both bare wire, should I just use a volt meter to determine what wire will be the source and the other the ground (I do not have a volt meter handy)?

 also lastly, this seems like a pretty easy built, it seems I will be running the whole system in series with one resistor, am I wrong?

 sorry to be a pest, I just have a thing where I need to have all the facts before I do something like this and since there are no real instructions for using a phone charger yet, I am therefore kinda nervous.

 thank you all in advance.

33 Ohm 5% 1/2W

http://www.radioshack.com/product/index.jsp?productId=2062312&filterName=Type&filterValue=1%26amp%3Bamp%3B%23047%3B2-watt+resistors

Thanks so much!!

 Again, I don't mean to spam the forums, I just wanted to be sure and I am paranoid like that.

 tomorrow I will no longer need the hat switch to shift views and that makes me beyond excited!

 Thanks again.

so when I go to radio shack tomarrow to pick all this stuff up, what resistor should I buy? I cannot seem to find a specific "E24" series so could I just take these results to the store and ask for the best choice?

Get two or three of these 33Ohms in the given link of dewey1 and some values of 27Ohm and 39Ohms. These unregulated phone chargers often gives higher voltage than indicated.
And resistors normally are 10cents articles. It seems to me, that RadioShack is overpriced. Have a look at some other Net electronic shops.

I have removed the small plug at the end of the AC adapter and it revealed two wires with no color code or anything, they are both bare wire, should I just use a volt meter to determine what wire will be the source and the other the ground (I do not have a volt meter handy)?

You can try wiring with the Leds (with resistor!), it works only in a sense. But the best is to get a cheap volt meter to test it. (Do not look on RadioShack: Overpriced and only 2-200mA range.)

also lastly, this seems like a pretty easy built, it seems I will be running the whole system in series with one resistor, am I wrong?

You are right.

The link I showed is for a quantity of 5 pieces.

The 33 Ohm will be fine for a range of 5.3 to 6.3 VDC.
Examples: (assuming a 1.28 V Vf)

1.46/33=44.24 mA at 5.3 VDC.

2.46/33=74.54 mA at 6.3 VDC.

There is no need to drive the LEDs at a maximum of 100 mA.

You are right, I didn't see the quantity.
LEDs are priced anyway.

The 33 Ohm will be fine for a range of 5.3 to 6.3 VDC.
Examples: (assuming a 1.28 V Vf)

1.46/33=44.24 mA at 5.3 VDC.

2.46/33=74.54 mA at 6.3 VDC.
There is no need to drive the LEDs at a maximum of 100 mA.

No,  there is no need to power them up to 100mA.
But in some case, depending on the webcam and filter you use, the brightness of low powered LEDs (<50mA) isn't enough for tracking correctly. Mainly for great angle head amplitude and well illuminated rooms. So it's not useless to have some extra resistors to try with higher current. 80mA is a good value in any case.