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Author Topic: LED COB blade -- a new design?  (Read 7639 times)

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Offline thatguyer

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LED COB blade -- a new design?
« on: March 23, 2017, 07:38:55 AM »
I am relatively new to saber-smithing (compared to some people here!), but I've been working for some time now on a saber blade built around COB (chip-on-board) LEDs. My goal was to produce the most intensely bright saber blade possible. At the same time, I wanted to support the "scrolling" on and off effect. To achieve these goals I soldered together a series of COB LEDs, each with its own ground wire that is controlled by a MOSFET. The theoretical peak power is over 100 Watts, generating many thousands of lumens. I had to add a brightness control or it blows out your eyeballs!

I have not seen any other saber based on these modules, so I figured I'd share my experience. I wrote a short Instructable describing how to build it -- search for "100 Watt light saber" (the forum won't let m embed a link).

Here is a video of the completed light saber (this is showing 40-50% of the max peak brightness):



I'd love to hear your feedback!

Offline Ridire Fíréan

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Re: LED COB blade -- a new design?
« Reply #1 on: March 23, 2017, 08:48:50 AM »
Aren't you a litte short to be a Jedi?  :cheesy:

Here's your link 100 Watt Light Saber

Just use the "Insert Hyperlink" button above the post text box.  It's the second from the left on the bottom row of square buttons that has an Earth icon with a corner folded piece of paper on it.

Looks great!  Off to read how you built it!

Offline EXAR KUN

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Re: LED COB blade -- a new design?
« Reply #2 on: March 23, 2017, 09:00:14 AM »
OMG so bright! Nice job!

I too am going to go read about this!



Offline thatguyer

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Re: LED COB blade -- a new design?
« Reply #3 on: March 23, 2017, 09:29:03 AM »
Aren't you a litte short to be a Jedi?  :cheesy:

Here's your link 100 Watt Light Saber

Just use the "Insert Hyperlink" button above the post text box.  It's the second from the left on the bottom row of square buttons that has an Earth icon with a corner folded piece of paper on it.

Looks great!  Off to read how you built it!

How surprised would you be if I told you I was 7 years old? ;-)

Thanks for the link. For some reason the forum system told me I don't have permission to add outside links.

Offline Sincenatic

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Re: LED COB blade -- a new design?
« Reply #4 on: March 23, 2017, 02:01:33 PM »
This is really awesome! The scrolling is very smooth; 14 segments that light up sequentially, with that brightness, is very, very, cool.

Offline JakeSoft

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Re: LED COB blade -- a new design?
« Reply #5 on: March 23, 2017, 05:23:55 PM »
Whoa, that's bright!

I'm just going to go ahead and say what we're all thinking: Let's see it outside in daylight.

Offline thatguyer

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Re: LED COB blade -- a new design?
« Reply #6 on: March 23, 2017, 07:20:53 PM »
Whoa, that's bright!

I'm just going to go ahead and say what we're all thinking: Let's see it outside in daylight.

OK, will do. I'll post a daylight picture over the weekend.
I'm also working on a more complete description of the electronics and the code. Really, the only big difference between what I'm doing and other projects on this site is the LED controller. See the pictures below. My setup is the typical "sandwich" of an Arduino, a DFPlayer, and a board to hold them. The LED controller uses a 16-channel PWM chip (PCA9685) with an N-channel MOSFET for each power sink.


Offline Sincenatic

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Re: LED COB blade -- a new design?
« Reply #7 on: March 24, 2017, 01:56:46 PM »
This is a very innovative project and I am very interested in further details. I see that you started out with traditional string blades, and if you will take photos, I recommend you to make comparisons with a string blade (if you still have one). If you also add information on these, it will be easier to put things in perspective.

Offline thatguyer

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Re: LED COB blade -- a new design?
« Reply #8 on: March 26, 2017, 12:58:44 PM »
I've been working on a new hilt, but I was able to make a video of the blade in daylight. It's a cloudy day today, but still pretty bright outside.



You can hear me struggling a little to reach the brightness knob, but in theory it can get even brighter than what you're seeing here. I think the limiting factor at this point is the internal resistance of the battery.

Offline JakeSoft

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Re: LED COB blade -- a new design?
« Reply #9 on: March 26, 2017, 05:05:09 PM »
That daylight footage is pretty convincing. Thanks for sharing!

Offline Obi_1

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Re: LED COB blade -- a new design?
« Reply #10 on: March 29, 2017, 03:07:29 AM »
Yes, the daylight photo looks very convincing indeed. Now I'm itching to see the wiring diagram!!! Congrats, good  job!

Offline Sincenatic

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Re: LED COB blade -- a new design?
« Reply #11 on: March 29, 2017, 09:11:46 AM »
I have only been into this hobby for about a year and even though I have seen the experiments (online) with neopixels, personally, my enthusiasm is really stuck on string blades. Using COB LEDs is interesting, but, I am still resisting any move away from string blades. What is very interesting is the LED controller. The standard in string blades is six segments, but I would really like to try out more. I use several strings with 3mm LEDs and I have never seen any wires behind the foam. I guess that the LED controller that you use could drive 14 segments of a string blade, or is there a “but” or “however” that I have not considered? (Maybe 14 segments would mean too many wires, but let’s say 10-12...).

Offline Obi_1

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Re: LED COB blade -- a new design?
« Reply #12 on: March 29, 2017, 12:55:15 PM »
Maybe Jake was right after all to use a Attiny :) With the chipset PCA9685 even a very small 8-bit controller could be used to program it, no need for PWM channels.
William, the challange is the driver stages, i.e. the mosfets. The chipset is as far as I understood a good PWM controller, but can output only ~20mA, enough for 1 LED, but not for many. Therefore you need mosfets, up to 16. So many to integrate on one board is a mess and a very narrow market segment. So you end up having to use an auxiliary board to house all your mosfets with enough surface to shed the heat. I guess this answers why all current single board solutions only support 6 segments. Nevertheless the LED string maniac stirs again in me... :evil:

Offline jbkuma

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Re: LED COB blade -- a new design?
« Reply #13 on: March 29, 2017, 03:33:05 PM »
I've ordered some COBs and I'm looking forward to the experiment!  Actually I have come up with a number of back-up projects for the COBs, and may regret not ordering more!

Offline jedimax

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Re: LED COB blade -- a new design?
« Reply #14 on: March 29, 2017, 05:00:42 PM »
Thanks for sharing. This is indeed a very bight blade.

 

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