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Thread: High powered LED project guidance

  1. #1
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    High powered LED project guidance

    Hi,

    My main goal is to be able to live-stream a video to approximately 1000 bright LEDs.

    I have individual 3W RGB LEDs that I want to be able to play movies on (50x20=1000 LEDs).

    Color Red Green Blue
    Vdc 2.0-2.5 3.2-3.6 3.2-3.6
    mA 400 350 350
    W 1 1.26 1.26

    I have been reading the OctoWS2811 and Teensy guides, but don't have much EE experience, so I'm not sure exactly what parts I need. I plan to buy the WS2811 IC chips and create LED strips by wiring 20 sets of 50 LEDs+WS2811 units in parallel. I'll control the strips with the Teensy and supply power to the LEDs separately through separate power supplies.

    Is this plan feasible, or am I missing anything important? Thanks for reading and for any suggestions.

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    The WS2811 LED drivers have a constant current output rated for 18.5mA maximum at 12V. This isn't going to drive those LEDs to full brightness. Are you planning to take the output from each WS2811 and amplify it to get the 300-400mA?

    Also, if you assume roughly a third of the LEDs are on at the same time, you'll need 0.4A x 1000 LEDs = 400A at 12V. That's a lot of power!
    Last edited by Neutronned; 01-31-2017 at 06:20 PM.

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    doesnt that mean that 400A is for one color of the 1000 leds? lol also, i dont think hes using ws2811?
    Last edited by tonton81; 01-31-2017 at 06:36 PM.

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    Senior Member PaulStoffregen's Avatar
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    Even if you successfully build 1000 high power 5 watt LED drivers (no small task!), have you considered where you will get 5000 watts of power?

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    @Neutronned

    I was planning to amplify the signal from each WS2811. For power, wouldn't it be possible to repurpose a couple ATX PSUs?

    @tonton81

    I am using regular LEDs but planning to attach each one to a WS2811 chip. Is this possible?

    @PaulStoffregen

    For starters, I wanted to build a small grid and power it with a repurposed PSU, but for the entire grid, I was going to get an electrical engineer to consult. Would this work if I wanted to make a 10x10 grid and used a 500 W computer PSU?

    Thanks for the replies.

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    Quote Originally Posted by tonton81 View Post
    doesnt that mean that 400A is for one color of the 1000 leds? lol also, i dont think hes using ws2811?
    Yes! 400A for one color. If the panel is displaying white (all on), that would be 3-4W per pixel, or 3-4 kilowatts of power. Say 3000W divided by 85% conversion efficiency = 3500W input power. That'll require a 120VAC 30A circuit.

    He mentioned using the WS2811, which I assumed meant one-per-LED. Assuming this moves forward, I'd actually try to find an off-the-shelf high-power LED driver, or design an interface board with the chip and drivers on it. Maybe design one that was 10x10 and build ten of them.

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    Quote Originally Posted by Neutronned View Post
    He mentioned using the WS2811, which I assumed meant one-per-LED. Assuming this moves forward, I'd actually try to find an off-the-shelf high-power LED driver, or design an interface board with the chip and drivers on it. Maybe design one that was 10x10 and build ten of them.
    Yes, I want to use one WS2811 chip per LED. What's the difference between amplifying the current of each WS2811 into the LED and buying an off-the-shelf high-power LED driver (could you link an example of one)?

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    For practical purposes, if you get ws2812b led strips, it is cheaper and convenient.

    https://www.aliexpress.com/wholesale...chText=ws2812b
    Here is a link for prices

    but I got about 300 ws2812b leds for 25 bucks which is cheaper than getting individual ws2812b ic. The drawback would be that the LEDs are not really reliable since I believe they are from a third party company. However since they all come with decoupling capacitors, I highly encourage getting these LEDs.

    In terms of power, I have not been able to find the exact current draw for the LED, but the most I heard is 60mA. So 60mA * 5V * 1000 LED is approximately 300 watts. You can get a 5v 60A powersupplies or preferably a little higher (5V 80A? if it exists?) so you don't kill the driver.

    In terms of connecting these all, you should use the octows2811 adaptor board which makes makes your life simple so that you don't have to convert the data voltage yourself and just use a single cat 6 cable (cat 5.e worked on my case) . Since you have 20 rows to connect but only 8 data pins, you will end up daisy chaining them. To make the LEDs evenly distribuited for each data cable, I would recommend using 5 data cables connecting to every other 4 50 LED strips

    http://a360.co/2komoVC

    This is the general concept I had for my own project.

    I created a 18*50 LED matrix (bought 3 5m ws2812b strips) and connected with 3 50 LED daisy chains and used 6 data pins.

    here is a video of it in action

    https://www.youtube.com/watch?v=uENVuqIFvuQ

    Sorry if my answer seems very confusing. English is not my best language

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    @mexicanhanu

    I know it is more practical to use LED strips, but I wanted to have extremely bright LEDs that can be seen clearly in bright sunlight. That's why I needed the 3W LEDs that I could only find individually.

    Thanks for the advice for the wiring. Your project looks really polished and thanks for sharing.

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    Hi,

    Have you done any experimenting with a small sample of regular WS2811-driven leds? My small experience with Neopixels and Dotstars is that they're pretty darn bright.

    --Michael

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    Quote Originally Posted by Michael Ward View Post
    Hi,

    Have you done any experimenting with a small sample of regular WS2811-driven leds? My small experience with Neopixels and Dotstars is that they're pretty darn bright.

    --Michael
    No, I haven't. I'll buy one of the brighter LED strips and see if that would work. Thanks.

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    I'm not sure but it was my impression that LED brightness in terms of (power per unit surface area of the die) does not vary much. The higher power LEDs like "3 W" LEDS simply have larger die sizes and bigger heatsinks, and the even larger ones (10 W etc.) have multiple die so you get more total light out, but any individual point has the same brightness. This being the case, you can figure out how much total light you'll end up with, just based on the amount of current the system draws, no matter which specific LED model you choose.

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    Quote Originally Posted by JBeale View Post
    I'm not sure but it was my impression that LED brightness in terms of (power per unit surface area of the die) does not vary much. The higher power LEDs like "3 W" LEDS simply have larger die sizes and bigger heatsinks, and the even larger ones (10 W etc.) have multiple die so you get more total light out, but any individual point has the same brightness. This being the case, you can figure out how much total light you'll end up with, just based on the amount of current the system draws, no matter which specific LED model you choose.
    That's really helpful. I ordered a strip of LEDs and will see if this works well in the sunlight. I'll post my findings here once they arrive.

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    Quote Originally Posted by pr4296 View Post
    That's really helpful. I ordered a strip of LEDs and will see if this works well in the sunlight. I'll post my findings here once they arrive.
    Thumbs up on this approach! If the Neopixel strip isn't bright enough, then move on to building the high powered version. In the meanwhile, you can build a 50x20 array with the strips and debug all your code without spinning the electrical meter off the wall! (Do meters still spin any more ????)

    Also, watch the construction weight. The weight of all those LEDs and associated drivers will start to add up and the structural challenges multiply. And pulling 3000 Watts out of the matrix will be fun. Think two hair dryers running full blast all the time!

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    Quote Originally Posted by Neutronned View Post
    Thumbs up on this approach! If the Neopixel strip isn't bright enough, then move on to building the high powered version. In the meanwhile, you can build a 50x20 array with the strips and debug all your code without spinning the electrical meter off the wall! (Do meters still spin any more ????)

    Also, watch the construction weight. The weight of all those LEDs and associated drivers will start to add up and the structural challenges multiply. And pulling 3000 Watts out of the matrix will be fun. Think two hair dryers running full blast all the time!
    I'll keep all of this in mind and will follow up once I get the parts. Thanks.

  16. #16
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    Quote Originally Posted by pr4296 View Post
    I'll buy one of the brighter LED strips and see if that would work. Thanks.
    That's a wise move. They're cheap and you'll learn quite a lot.

    The most common cause of failure for these large LED projects is underestimating the power requirements and conductors needed to carry that power to the LEDs. It's especially tempting to skimp on power delivery after spending so much on LEDs, but solid power and good grounding is critically important for these sorts of projects to be successful. Keep that in mind as you plan for a larger project.

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    Last edited by Neutronned; 01-31-2017 at 11:05 PM.

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    Woah those are so expensive. I'd much rather use less bright lights at 1/10th the cost, but it's cool to see that those exist.

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