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View Full Version : LED string evolution - this will change the way we think about LED strings!



Obi1
03-02-2016, 01:36 AM
Hi guys,

I want to share a new and exciting LED string technology emerging. It has the potential IMHO to change the way we think about LED strings.

Who did not dream about building one day an LED string saber with the possibility for color change? Moreover, people assembling their LED strings know the pain of suddenly loosing an LED, solder joint coming loose, etc.

This just might be the answer to both of these major wishes. There is a new, prefab LED string on the market called neopixel (type WS2812), you can find a lot of offers on ebay, for instance:
http://www.ebay.de/itm/251739289830?_trksid=p2057872.m2749.l2649&var=550665352528&ssPageName=STRK%3AMEBIDX%3AIT

Technically speaking these stripes mount LED modules on a flexible PCB, which can be cut at any LED position. The LED modules integrate:
- 3 colour, RGB LEDs in one package
- together with a tiny controller IC already integrated into the package of the LEDs

The controller can be programmed with a 1-line serial interface. It has for each of the colours an 8-bit PWM (pulse width modulation), summing up to 24-bit/LED module. The serial interface runs through the whole stripe, i.e. the aggregate of all LED modules act like a giant shift register, which can be programmed in one go.
To program it, you need only therefore 3 wires:
Wire#1: VDD supply (rated at 5V, but I tried, it's crazy, but it works down to 1.8V! 3.7V is ideally suited to supply the stripe!!!)
Wire#2: 1-line serial signal to program the stripe
Wire#3: GND

That's all!

The programming of the stripe can be done so fast, that you will not notice, so features like flicker, FoC etc. can be implemented very easily. Since ALL LEDs can be programmed individually (yeah, no joking), and the LED stripe can be cut at any joint, it would be ideally suited for Kylo Ren type crossguard sabers. You just make a stripe for the main blade, then 2 sub-stripes for either half of the cross guard, and connect the 3 stripes in series, programming them all together.

As to stability: they are mounted on a PCB, the backside of the stripes have a string 3M adhesive tape, for a blade you can simply glue 2 stripes together back-to-back, wrapped in a diffusing foil it will allow you to duel with it in my assessment. Looks very solid.

I made a video showing how it can be used for lightsaber blade.
(Disclaimer: sorry for my bad spoken English, just ignore my ranting and enjoy the light show)

https://youtu.be/lyk8riXgIzM

If you like Bruce Springsteen, you can also chill out at the end of the video with one of his hits :)

Mineral
03-02-2016, 03:38 AM
Super cool!

NanoRex
03-02-2016, 11:21 AM
I've seen these before, but for some reason I had never even thought of using them in a string blade. They seem perfect!

Silver Serpent
03-02-2016, 11:28 AM
That's a nice light show you've got there. The flexible PCB could improve durability for high-impact applications (like lightsaber blades). It would certainly save some time over building your own LED strip.

CET
03-02-2016, 01:12 PM
They can be individually programmed? I detect scrolling effect possibilities!

NanoRex
03-02-2016, 01:24 PM
They can be individually programmed? I detect scrolling effect possibilities!

Lol, check out the video. Doesn't take long to detect scrolling effects XD

CET
03-02-2016, 03:11 PM
Lol, check out the video. Doesn't take long to detect scrolling effects XD

:shock:

I gotta get me one of those

Tyrant
03-03-2016, 08:29 PM
so when i was researching what type of lighting solution i wanted, tried el wire lights, then some 5250 (?) led, the problem i kept running into is that because these strips project outwards it creates a lot of uniformity issues, also despite pushing 9 volts to the ones i was using they were significantly dimmer then what i use now in my strings. i would even make like 5 strings and get near perfect in the spacing between spacing for the next strip to compensate but still very noticeable uniformity issues, which was my whole reason for not using in hilt led systems anyway. good luck, would be interested to see how these turn out if you get a working model.

edit: missed the video you posted when i first read through your post, looks cool but i can still see the dim spots between modules even on camera where due to how cameras bloom everything to a huge degree it makes it hard to see such inconsistencies.

redpaw70
03-03-2016, 09:01 PM
very nice! i see a ton of possibility's

Zacharyah
03-04-2016, 06:30 AM
That is pretty rad. It would be interesting to combine this with impact sensors at intervals along the blade and then do the flash on clash at the point of impact rather than the whole blade

Silver Serpent
03-04-2016, 06:51 AM
...despite pushing 9 volts to the ones i was using they were significantly dimmer...

I'm going to assume you were using a 9v battery? Just FYI, 9v batteries are only good for low-current applications. They don't push out much current at all. If your project needs more than a couple hundred mA, then a 9v battery is not going to do the job.

You might consider revisiting those old projects with a different power source. You might be pleasantly surprised.

Obi1
03-04-2016, 03:24 PM
If you supply these LED modules with 9V, you can only fry them.
Come to think about it, Silver Serpent had a point there, probably the 9V battery could not churn out enough joice, so the voltage dropped. You can consider yourself lucky for that.
Use a regular 3.7V battery and these guys will be very grateful and quite bright.

As to uniformity, completely right. To compensate for that you need to etiher make a very good diffusing or increase the LED density. Or, but the same LED in the regular through-hole version (they exisst) and build a traditional LED string saber.

FoC: I was pondering on the same topic. Well, if you can detect the position of the clash, let me know, I'm all ears! That would be EPIC! In the meantime I considered a practical approach: in a duel the blade mostly get smacked somewhere close to the middle, therefore that is where the FoC has to happen. I will experiment with it, I'm sure it will look cool :)

Tyrant
03-05-2016, 12:04 AM
It was a 110 to 9 volt power supply I now use for light salt water etching. I could never resolve the uniformity issue despite foam wrap and the toss diffusion tube but looking forward to progress updates. The video is a single 1 sided string correct?

dezeni
03-05-2016, 12:57 AM
Post what you guys have good stuff. And have them throw the switch
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Obi1
03-05-2016, 12:53 PM
In the video I use the 60LED/m type, 50 LEDs on each side, i.e. 2 stripes attached and glued back-to-back, summing up to 100 LEDs.

Although with the 60L type you are right, diffusing is a challenge, I just tried today the newest 144L type, with an transwhite heavy duty TCSS type blade with a diffusing tube inside, and it's very uniform even without any additional layer of diffusion.Very promising!

FenixFire
03-05-2016, 06:31 PM
Are the 9v, all of the rgb accent strips, similar to these, that I have ever built into trade show displays and cabinetry were intended to be used with the 12v ac-dc converters. Just asking I did not check the specs, just looked identical to most other accent lighting strips sold for cabinets and home accent lighting.

Zacharyah
03-07-2016, 07:27 AM
I wonder if you could use a strain gage at the base of the blade to detect deflection. You'd have to figure out an algorithm that would compare the strain gage output to the accelerometer input, because the blade would flex differently at different speeds and hit strengths, but I think you'd be able to figure out the point of impact from initial speed X, impulse Y, and blade flex Z.

TheSilverDark
03-07-2016, 07:50 AM
I saw these a while back and thought the exact same thing! Maybe turn on LEDs off and on rapidly to make a strobe saber xD

Tyrant
03-08-2016, 01:23 AM
Awesome keep up the work, my original post wasn't meant to be discouraging

How would one eventually program for ignite, shimmer, clash, shut down? Would these require an additional arduino style pub or will what plector have today be able to control the effects and rgb changing?

Once I get most of my sabers for the year done, I'm looking to start work on a rgb string that should be able to be controlled by any of t b en cards with color mixing

Obi1
03-08-2016, 07:22 AM
I'm currently working on an Arduino breakout board called DIYino, which will be able to handle all 3 types of blade/lighting styles
- HP LED
- LED strings
- neopixel

But Erv's CF_LS could be uses as well for this purpose if the proper algorithm is included in the code. To give you a feeling, based on the algorithms found on the net, I was able to tweak my code to drive neopixels instead of LED strings in a matter of a few hours. If I could do that Erv could do that on an even higher level.

I wrote CF_LS, because you will need those 6 lowside switches. Not for the same purpose as for an LED string, but need you do them still :twisted:

Thalan the Exiled
03-15-2016, 02:35 PM
Has anyone been able to find these in the US? These look very promising for a display saber or one that doesn't have FoC. I would love to find the ones linked in the original post in The US. From the description in the ebay listing they have a forward voltage of 5v at least if I read it right. That shouldn't be to hard to accomplish with a little work. And if there is a version with more led per in/cm then the uniformity issues would be solved. Please link if you have found them in US. Thanks

CET
03-15-2016, 05:14 PM
I've found similar things, except they're all 12v. :?

Thalan the Exiled
03-15-2016, 10:21 PM
Exactly everything on ebay says 12v or more. Would love to find these in a 5v setup

NanoRex
03-16-2016, 08:41 AM
Adafruit?

Obi1
03-21-2016, 02:51 AM
The are specified to work with 5V supply but that does not mean they use LEDs with a forward voltage of 5V!!! Actually in the video you can see that you can go down considerably with the voltage, common 3.7V supply would be more than sufficient. If you go above 3.7V, most of the current will be wasted over some kind of clamp circuitry to protect the LEDs which have standard Vfs (red ~2V, blue+green ~3V).
I do not know about 12V...

profezorn
05-12-2016, 12:12 PM
Most of these strips are 5v, but some are 12v. They are usually slightly more expensive as they include extra regulators to lower the voltage, which is then fed to the chips.
The nice thing about the 12v-strips is that they can usually operate in a fairly wide voltage range (like 4 to 14 or something), and the higher voltage means less amps and less power lost as heat.

FenixFire
05-12-2016, 03:05 PM
Most of these strips are 5v, but some are 12v. They are usually slightly more expensive as they include extra regulators to lower the voltage, which is then fed to the chips.
The nice thing about the 12v-strips is that they can usually operate in a fairly wide voltage range (like 4 to 14 or something), and the higher voltage means less amps and less power lost as heat.

5v ones are wired for Arduino style boards. The 12v ones are intended to be used with 12v dc converters for home accent lighting applications, such as cabinetry underlighting.

profezorn
07-31-2016, 10:18 PM
After experimenting with WS2811-compatible strips, I have concluded that building LED strings out of PL9823 LEDs works better. It's a lot more work, but the diffusion is far superior.
For more information, see this page: http://fredrik.hubbe.net/lightsaber/blade1.html

CET
08-01-2016, 08:55 PM
That's an interesting method you took for the LED string. Do you have any idea what will happen when the blade flexes on impact?