12mm LED strand WS2801 problem

by elyts on Thu Aug 09, 2012 7:12 am

Hey,

I purchased two strands of the 12mm LED pixel strands to build a 50 channel ambilight. I read all tutorials on adafruit.com and connected the wires accordingly. But the LEDs wont glow.
I have a 5V/DC 4A power supply and connected the strands with some jumper wires to the Arduino UNO rev3. When I upload the test program to the Arduino with every wire connected like in the tutorial (I tested port 11/13 and 2/3 ), nothing happens. I tested both strands separately and when connected to each other. I made some pictures of the wiring:
http://imgur.com/qIwdb,7f8Vw,1bYtM,a3VA2

I dont really think that both LED strands are broken, but its more likely a software or a wirering problem. I apprechiate every kind of help.

Greetings,

elyts
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Re: 12mm LED strand WS2801 problem

by adafruit_support_bill on Thu Aug 09, 2012 8:36 am

Can't really analyze the wiring to the Arduino because all the wires are the same color. Can you post one that clearly shows both ends of those jumpers?
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Re: 12mm LED strand WS2801 problem

by elyts on Thu Aug 09, 2012 8:51 am

I hope those two are better:

http://imgur.com/mSFCB,g3gew

yellow is in 2, green in 3 and blue in GND.

I just found out something else: I took a voltage tester and tested the LED strang. There was voltage on every cable. Is it supposed to be like that? I mean, even on GND cable was voltage.
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Re: 12mm LED strand WS2801 problem

by adafruit_support_bill on Thu Aug 09, 2012 9:29 am

It looks like you have the right one, but just to be sure, you should be wiring to the end with this connector:
Image
You might also want to verify how it is wired to the pixel (just in case there was a factory error and the connectors are wrong)
Image

And have you verified that your program is using the same pins you are connecting to?

I took a voltage tester and tested the LED strang. There was voltage on every cable. Is it supposed to be like that? I mean, even on GND cable was voltage.

What kind of voltage tester are you using? The best way to measure is with a multimeter between the GND and +5.
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Re: 12mm LED strand WS2801 problem

by elyts on Thu Aug 09, 2012 9:50 am

I dont understand what you mean with the first picture:(

I used one of those to test if there is voltage on a cable:
http://picture.yatego.com/images/459ba4 ... 0x60mm.jpg

Is there another way to test if the LEDs work at all?
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Re: 12mm LED strand WS2801 problem

by adafruit_support_bill on Thu Aug 09, 2012 10:32 am

I dont understand what you mean with the first picture:(

Just trying to verify that you are connecting to the 'input' end of the strand. If you connect to the 'output' side, nothing will light up.

That tester looks like it is for measuring AC voltages. It will not work for DC.
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Re: 12mm LED strand WS2801 problem

by elyts on Thu Aug 09, 2012 10:40 am

I connected the cables coming from the end with the black chip facing me to the Arduino. But just out of curiosity I'm going to try it in the opposite direction.

Update: When the strand was connected in the wrong direction, one LED at the end of the strand flashed blue for a second. After that nothing happened anymore. Dont know what this is.
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Re: 12mm LED strand WS2801 problem

by pburgess on Thu Aug 09, 2012 11:56 am

Hi there,

The LED tutorials have changed recently, so I just want to confirm we're on the same page:

If you're following the "12mm LED Pixels" tutorial (with example code), that one uses Arduino pins 2 & 3 (plus ground).

If you're following the "Adalight Project Pack" tutorial (w/code), that one uses pins 11 & 13 (plus ground).

The wiring looks OK from here. Another possibility is that the plug on the power adapter might not mate quite properly with the DC jack. Remove the power adapter and try running an extra wire from the Arduino's 5V pin to the red wire on the LED strand...this is not suitable for permanent installation, but is usually OK for quick tests.
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Re: 12mm LED strand WS2801 problem

by elyts on Thu Aug 09, 2012 12:13 pm

Ok, with the 5V of the Arduino all LEDs light up and work - that's a relieve. But what now? Do you think the Power supply adapter is broken or the female jack? Or did I attach the female jack to the wrong cables(red was + and grey was -, both cables were at the opposite end of the Arduino)?
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Re: 12mm LED strand WS2801 problem

by adafruit_support_bill on Thu Aug 09, 2012 12:33 pm

What power adapter are you using? Marking on output wires are not entirely reliable. I always check polarity with a multimeter.
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Re: 12mm LED strand WS2801 problem

by elyts on Thu Aug 09, 2012 12:48 pm

Ok, I now what the problem is now. Its the female jack. Either the pin inside the female jack is too small to get in contact with the plug of the power supply, or its just broken. When i just put the red LED cable inside the power supply plug and the grey one on the outside, everything works fine. So the problem is definitly the female jack. Do those things come in different sizes?
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Re: 12mm LED strand WS2801 problem

by adafruit_support_bill on Thu Aug 09, 2012 2:10 pm

There are a few different pin diameters. We only carry the one size that works with all our power supplies. RadioShack usually carries a variety of adapters. You might find something there.
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Re: 12mm LED strand WS2801 problem

by pburgess on Thu Aug 09, 2012 5:12 pm

The DC jack adapter is sized for a 5.5x2.1 mm barrel (that's outside and inside diameter)...it's a pretty ubiquitous size, used by Arduino, some external hard drives, the power supplies in the Adafruit shop, etc.

If you have a power supply with a different inside diameter fiddly bit (it happens, there's like a billion variations), you'll need to either cut off and replace the barrel with a 5.5x2.1 mm type, find a different DC jack adapter that mates with it, or use a different power supply that already has the right size jack.
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Re: 12mm LED strand WS2801 problem

by elyts on Fri Aug 10, 2012 5:09 pm

My power supply's plug is 5,5x2,1mm as well. I think the damn thing was just broken. I purchased it at one of the distributors on adafruit.com. I went to an electronic parts store today and bought a new one. Now everything works fine :)
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Re: 12mm LED strand WS2801 problem

by fikri_m on Wed Feb 20, 2013 2:02 pm

Hi there..

I've a question about the LED. Can I use another type of LED ? Let's say LED analog RGB strip ?
We knew that there are no chip driver on that analog LED. Can you tell me please how to use the analog RGB strip as well as the 12mm LED that have a driver chip inside it ?. It mean I have to add some IC, like ULN2003,ULN2803 ?

Thank you :)
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