First LED-String Lightsaber - Brightness problem

Hello,

I`m currently working on my first LED String Lightsaber.
I used 120 of 5mm Nichia red-LED`s , drilled a cone in the head to increase the angle and put them together. I don`t want a scrolling effect on the blade (i use the spark 2 board later) so i thought i don`t need to put the LED`s into segments like many other people do it.
However, when i light it up, the LED`s at the point where I supply the power are the brightest - decreasing going through the ladder. If i do the power-input at the middle of the string, it`s better.

So my question: Am i doing something wrong or has there to be segments?

Thanks in advance

im from Germany btw - sorry for my english :-)

Go for the segments. It will allow the power to be distributed more evenly. You can still light them all up at one time if you don't want the scrolling effect.

Okay,
so i tried to wire it up with segments like its shown here :http://www.fx-sabers.com/forum/index.php?topic=13567.0
However - same outcome.

I guess i need a "Seriallel"-wiring?
I took a bit research on that and because of red LED`s i need the "Seriallel class III"-wiring(not sure why)?!
I read the instructions on the plecter labs website (http://www.plecterlabs.com/Media/CF-...P-V6.50-GB.pdf) - Page 27

I understand the Seriallel II class but, dumb as i am, i don`t quite get the class III.

A little drawing of a full segment like at page 27 but for serial III would be incredibly helpful!

Thanks

EDIT: Nevermind - got it!

Quote:

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Originally Posted by TeeBeutel

Hello,

I`m currently working on my first LED String Lightsaber.
I used 120 of 5mm Nichia red-LED`s , drilled a cone in the head to increase the angle and put them together. I don`t want a scrolling effect on the blade (i use the spark 2 board later) so i thought i don`t need to put the LED`s into segments like many other people do it.
However, when i light it up, the LED`s at the point where I supply the power are the brightest - decreasing going through the ladder. If i do the power-input at the middle of the string, it`s better.

So my question: Am i doing something wrong or has there to be segments?

Thanks in advance

im from Germany btw - sorry for my english :-)

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What type of battery(s) are you using?

i use 2 18650 Li-Ions wired in paralell so i get 3,7V with capacity of 2 Batteries.
My soundboard (Spark 2) needs 3,7 V so i cant go for the serial setup.

What's the voltage and ma usage for the leds you are using? What's the forward voltage? decent leds will have the same forward voltage as recommended and your only issue is ma used by each led there are a few tricks that you can use to be able to only use 1 segment

try connecting one lead to the bottom led (hilt end) + and the other to the top led (tip end) - this may help