First String Blade Build Log

[CET]

I've been looking at doing a string blade for a couple of months now. I don't entirely understand how the electrical part works yet, but that's part of what this process is about.

I found some straw hat LEDs on Amazon that have a nearly 180 degree viewing angle. Since the light is shining out instead of just up, it should maximize blade effect.

I got some cheap little 3mm LEDs at my local electronics supply store to practice the bending technique. As you can see on the first couple of LEDs, my technique wasn't so good, but starts to become more consistent towards the bottom. I put a dot of solder at each joint and cut off the extra leg length. Is it recommended to keep the extra length of leg? I just figured they would get in the way, so I trimmed them.

I'm not sure how the resistance math will work, so I just put a beefy 2 watt resistor on there to keep things from burning out. If anyone can help me with how the resistor math works with string blades, it would be much appreciated.

[Silver Serpent]

If your LEDs are wired in parallel (all positives connected to each other, all negative connected to each other), then you will use the forward voltage of a single LED, and add up all the current values for each LED. Typically those LEDs are 20mA each, so 10 of them together would be 200mA as an example.

Calculate your resistor based on the forward voltage and the combined current.

[CET]

I got the straw hat LEDs today, but I'm honestly not impressed with their brightness. 100 of them at 20 mA each are putting out 2 amps. I calculated that I needed a 1ohm resistor (which I have plenty of), so I would imagine that it's just that these LEDs are not that bright. :-/

Any suggestions for LEDs that will give a bright blade?

[NanoRex]

Have you tried just running one LED at 20mA? Maybe there was an error in your calculation.

[CET]

I pulled off the resistor and it looked just as bright to me. Maybe once I wrap it up it'll look better.

[NanoRex]

That stinks. It doesn't look too bright in the picture. What was the millicandela rating on the LEDs?

[mikesibe1]

Super bright clear LEDS in the color of your choice. Then wrap the LEDS in packing foam. Then buy a blade and a blade diffuser from the customsabershop

[CET]

I created an adapter so that I can just plug my blade can be removable.



I got some thin packing foam today and wrapped my LED string and stuffed it into my blade. Problem is, I kept breaking solder joints, so I had to remove the string, unwrap it, resolder and rewrap. After the 5th attempt I felt the bogans build up, so I walked away. Any blade stuffing tips that might prevent solder joint breakage?

[TeeBeutel]

Stick the whole string in a proper shrink tube before diffusing

[Sincenatic]

I have just finished my first string blade and I didn?t experience that problem. I saw a recommendation from Ken Hampton that when you attach each LED it is very important to press the joint firmly. He explained that without this step you run the risk to use too much solder which causes shadows on the blade. I followed that recommendation and my string was quite ?stiff? even before soldering. Hence, it is more the legs of the LEDs that holds the string together, rather than solder. Of course I cannot know if this is the reason for your problems, but it could be. My recommendation is that before soldering; make sure that the LEDs are not dancing around.