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Topic: How to connect WS2811 5050 RGB LED Strip to Arduino/Genuino Uno? (Read 3428 times) previous topic - next topic

Profwombat

I recently bought a Genuino Uno, and the following LED strip:
http://www.ebay.co.uk/itm/322206934135
I should start by saying that I have no prior experience in electronics/using an Arduino - I am a programmer, and was hoping to easily set this up so I could program them as I want.

How do I connect this strip to the board? I have tried a few ways and nothing has worked. When connecting the 12v and ground wires to an external power supply, all of the LEDs flickered briefly, but beyond that they have not lit up at all.
Also, once connected, which library should I use to program them/how should I begin? I have been trying the Adafruit NeoPixel library, but not sure if this works with non-adafruit products?

Again, I have very little experience or understanding of any of this (and no desire to understand in detail), so please explain simply how to correctly connect them. Any help is appreciated.

PaulRB

Quote
I am a programmer... no desire to understand in detail
Those two statement seem to be at odds with each other! How do you manage to do one if you don't do the other?

Yes, you should be able to use this strip with Arduino. You have the choice of the Adafruit or the FastLed library. Some tips: don't route the current for the strip through the Arduino board, but they must have a common ground.

Profwombat

I have connected everything as shown in the images (sorry, they failed to upload).
The green "Data in" wire goes to digital port 6 on the arduino
The red "12V" wire goes to the + port on the external power supply (an AC-DC converter set to 12V)
The white "Ground" wire goes to the - port on the external power supply
There is also a paper clip (as a makeshift wire) connecting the ground port on the arduino to the - port on the external power supply

The lights never show any response to the arduino. As mentioned before, when they are plugged into the power supply, they briefly flash as shown in the image "led_flash.jpg"

What am I doing wrong? Why isn't it working? How do I fix it?

The code I am using (the demo provided on the FastLED github page):
#include "FastLED.h"
#define NUM_LEDS 60
CRGB leds[NUM_LEDS];
void setup() { FastLED.addLeds<NEOPIXEL, 6>(leds, NUM_LEDS); }
void loop() {
   leds[0] = CRGB::White; FastLED.show(); delay(30);
   leds[0] = CRGB::Black; FastLED.show(); delay(30);
}

Reburg99

Try changing your set to:
void setup() { FastLED.addLeds<WS2811 6>(leds, NUM_LEDS); }

They might not be recognized due to selecting NEOPIXEL.
   

Profwombat

Try changing your set to:
void setup() { FastLED.addLeds<WS2811 6>(leds, NUM_LEDS); }

They might not be recognized due to selecting NEOPIXEL.
   
Just tried that, hasn't changed anything, they still don't respond at all. Thanks anyway.

Also see this photo:
http://zsmith.ddns.net/photos/led_connection.jpg

PaulRB



A photo where we could see all the important connections in focus would be nice.

Profwombat

Sorry, here is a better one, with annotations:


Thanks for any help you can give.

PaulRB

That's better. So there are two red (12V) and two white (ground) wires from the strip. You could dispense with that embarrassing paperclip and connect the second white wire to Arduino's ground. (Was that the Microsoft paperclip by the way? If so, well done catching him. Deserved what he got).

The usual recommendation is to have a low value resistor, eg. 220R or 330R, in series with the data line. Worth a go given the situation. The other recommendation is a large cap, eg. 1000uF, across the power lines to the strip.

Reburg99

is there an arrow with the direction of data flow on the strip?  If so, make sure you're connected to the input side and not the output side.  It's irreverent for power, but data will only flow in one direction.

Profwombat

The usual recommendation is to have a low value resistor, eg. 220R or 330R, in series with the data line. Worth a go given the situation. The other recommendation is a large cap, eg. 1000uF, across the power lines to the strip.
https://www.amazon.co.uk/dp/B0091GPLNA
Would this be the correct capacitor? And so do I Just place it so that each terminal (idk if that's the proper term) touches one of the wires? Or both terminals touching both wires?

https://www.amazon.co.uk/dp/B01I7S2TPU/
And this one for the resistor?

Will these likely allow me to use the LEDs? Or are they just a step closer to a solution?

is there an arrow with the direction of data flow on the strip?  If so, make sure you're connected to the input side and not the output side.  It's irreverent for power, but data will only flow in one direction.
Yes, the arrows flow away from the side into which I have put the wires, I assume this is correct.

PaulRB

Both of those components are fine. Just don't get ripped off, like paying 25p each for resistors or £1.99 postage on something the size of a peanut.

We don't know for sure they will fix the problem, but they are recommended, and we have to try something.

Quote
And so do I Just place it so that each terminal (idk if that's the proper term) touches one of the wires? Or both terminals touching both wires?
Connect the positive to red and negative (indicated on electro caps by a black band with "-" symbols) to white. Don't short 12V to ground unless you want your house to burn down.

What is the spec of the PSU? Does it have the current capability for your 5m strip?

Profwombat

OK, I have ordered that but will take about a week to arrive. Then we'll see if it works.

Reburg99

Do you have a meter?  Have you tested the output of the power supply to verify it's outputing 12v and to make sure you have + to + and - to -?  After closer inspection of your pictures, are you sure you're getting a solid connection to the power supply? 

Profwombat

I don't have a meter, no, but I would hope I think the power supply should be trustworthy.

The connections may indeed not be very solid. How should I fix this? What is the proper way to connect those wires to that kind of plug?

Reburg99

Not really sure if there's an adapter for that specific connector or not.  You can cut the connector off and splice the bare wires together, just be sure to tape (electrical tape preferred....) or heat shrink the connections to prevent a short.  you could try folding the wire back on itself, this way your putting the jacketed portion and the bare portion into the plug at the same time.  This will at least fill more of the gap.



If you don't have a meter, how are you sure you have the positive and negative hooked up properly? 

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