Sup Anons,
I have a somewhat interesting project, which I will share with you later when I am nearer to the completion of it, but for now I need your help.
I have 125 RGB LEDs. I have to controll every one of them individually, if possible with brightness regulation. What kind of a controller would I use? I can imagine controlling 5 or 6 normal LEDs, but 125 RGB ones kill my imagination. That's a total of 375 outputs I have to be able to control. What the fuck would I use?
>>946850
You can use pretty much any microcontroller to do this. Just look up multiplexing and chaining shift registers, although codewise it will be pretty tedious.
>>946851
That's a good idea I actually forgot to consider, thx!
>>946850
Look up how people wire and control LED cubes. Exact same principle. You're going to need an Arduino and maybe some LED drivers.
well, the WS2803 can handle 18 LEDs and is programmed serially. they can be chained, so 21 chips could do the job. less if you can think up some shortcuts.
Soemthing like this, right?
Ok, I think I get now what the led cube dudes do.
Now lets say I expand to 1k RGB LEDs instead of 125. That would make 3000 outputs in total. I think expanding that multiplexor schematic to 3000 outputs would be rather retarded. What would I do in that case?
>>946851
Using a matrix cuts down on the LED brightness. If it's a 10x10 matrix an "on" led is only getting power 10% of the time so it's 10% of it's normal brightness.
If you want each LED to be as bright as possible use a row of shift registers to get a huge number of outputs. There are chips like WS2803 designed for this application that will make things easier.
>>946850
>I have a somewhat interesting project, which I will share with you later when I am nearer to the completion of it, but for now I need your help.
>I have 125 RGB LEDs. I have to control every one of them individually, if possible with brightness regulation. What kind of a controller would I use? I can imagine controlling 5 or 6 normal LEDs, but 125 RGB ones kill my imagination.
what you really want is WS2812 LEDs, also called "neopixels".
they are connected in serial, and you can control the color and brightness of each individual LED.
go buy yourself 125 of the WS2812 RGB LEDs, and then you can control them with 1 wire from a (real-time) microprocessor (like arduino/pic/propeller, but not rpi!).
if you can shop on aliexpress, look for "ws2812 rgb heatsink".... this is 100 of these leds on little pre-cut circular PCB boards, that only costs around $15.
Most US places charge at least 50 cents for these things, some places charge over a dollar each. China sellers charge about 15 cents.
if you get the China ones, then get your arduino there also.
China arduino megas cost $6-$7 now. If you want something physically smaller, the China arduino pro mini 16mhz 5v boards only cost $2. Maybe 50 cents more for a cable, if you don't got one.
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"but I already bought some other kind of LEDs, and can't return them"
do whatever you want, but it would probably be way easier and quicker to use the neopixels for this (and likely cheaper also overall)
>>946900
No-no, I have not bought anything yet, I am in the planning phase for now. The problem is, I intend to go as high as 1000 leds, propably, so prices around 10 cent for a led would be preferable.
The idea is great though, just checked out aliexpress and I can get them for around 15 cents a piece, that's actually pretty cheap.
Can you link me something where somebody used them? I have found this guide, is it reliable when they talk about usage and shit?
https://learn.sparkfun.com/tutorials/ws2812-breakout-hookup-guide
>>946863
Not if you use a latch for each LED. An off-the-shelf SRAM would do the trick.
Hell, even a transistor and a cap would do. You're effectively building a DRAM cell. Your controller could overdrive and underdrive it for better response time.
>>946850
If you're going for 1000 LED's I think both of these videos are worth a watch. A bit hardcore at times, but stick with it. There's a hell of a lot of info from someone who does exactly this for a living.
Driving LED matrix displays with an FPGA:
https://www.youtube.com/watch?v=Sq8SxVDO5wE
DIm & Dimmer - Design for test & installation:
https://www.youtube.com/watch?v=cQWnLOCGpXM
Unrelated but similar problem
My brother managed to get me a 32x32 matrix for free, but for whatever reason it has 2x10 IDC connectors for input and output (most of the matrices available use 2x8 connectors), and I can't find a pinout on google or anything to save my life.
Anyone used one of these before? If so, some guidance on how to write this thing to an arduino would be greatly appreciated.
>>947071
I had a quick look and couldn't find anything either.
There's a fair chance your connectors are a clone of the Adafruit 'standard' matrix connector plus some extra power or ground pins. Map out all the VCC, 3V3, GND pins you can with a DVM on continuity. If you're really lucky, there'll be another 4 GND pins on one end and all the other pins will be the same.
>>947205
Alright I'll give that a try. Wasn't honestly expecting a reply, so thanks for your time
>>946851
Code wouldn't be more complicated than controlling just 5 in the same manner.
>>946900
>ws2812 rgb heatsink
These are nice. Saves on having to bother with the extra cap for each one.
>>946902
>1000 leds
That's over 10 amps of current drain. Do you plan on making them update much? If so, ws2812 might not be the best choice.
Sparkfun is generally a good source for this stuff.
If you want, I can give you my pretty basic C code I wrote for a demo strip of 8.
>>947245
Yes, I would be very interesting in a code example. Thanks for the sparkfun suggestion, but I live in europe, so that's not an option for me.
>>1000 leds
>That's over 10 amps of current drain.
Yea but it's only @ 5 volts... you can buy 30 amp 5v "CNC" power supplies for about $35 shipped
>Do you plan on making them update much? If so, ws2812 might not be the best choice.
I haven't used any of them yet--but from what I've seen, I don't think 1000 in a row would be a real problem unless you were trying to make a monitor display with them.
I know people IRL who have the remote-control Chinese 300-LED strip lights that change color, and they use these kinds of LEDs,,,, and you can't really tell that they are updating down-the-line, if you get what I'm saying. When you press the button for it to change from one color to the next, the whole thing basically appears to change at once.
>>947463
>remote-control Chinese 300-LED strip lights
Are you sure those are the "individually addressable" ones? Because most of the RGB strips just have separate power lines for each color and control the colors directly with PWM.
