Read the statement by Michael Teeuw here.
Led strip problem
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@Anthony on the output of the power supplies is a +5 or +12 and a ground…
are all the grounds connected together at some point or are they all separate… usually to stop interference like this you need to bind the grounds…
the input side has them grounded together… but not the output side
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@sdetweil oh sorry. on the power supply which powers the arduino I have also connect 2 small 12v fans. So the grounds of the fans and the ground of arduino yes they are common. Do you think this is the problem? So if disconnect the fans the leds should work? but why this is not happening from the beggining and it happens only when the screen turns on?
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@Anthony I suspect the driver for the TV is emitting radio noise, which the leads for the WS2812 is picking up as data.
Did you power both ends of the LED strip? It’s good practice unless the strip is very short. This will do two things, first, ensure level LED color throughout the strip, and second, help the data line recognize it’s data over the noise.
There may be other things you can do to improve the data control. If you know anyone in the amateur (ham) radio community, you may be able to ask them about Radio Frequency Interference. They have the knowledge to help you isolate the issue and solve it.
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@BKeyport No. The led strip has 30 leds per meter and I use 59 leds so it is 2 meter long and I have powered it only from one side with a 5v power supply. I read somewhere that a common problem is if HDMI cable is too close to power plug this happens and that they should be at least 30cm away from each other. My TV’s hdmi is just below from the power hub. I think I will disconnect everything and reconnect-test one by one and I hope I will locate the problem.
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@Anthony You might consider somehow powering both ends. You’ll find better performance of the string because it’s that long.
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@Anthony - In my CNC work I have run into a lot of electromagnetic interference. One thing that has helped a bit is to add ferrite cores to most of my input wires at both ends. Especially any USB wires.
Your friendly electronics shop should have something like these. -
@bhepler a lot of times in longer runs, the data line on the strip itself is the antenna.
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@bhepler That is a very good idea I will definetly try it. I hope I will find those ferrite cores in one of my local electronic stores. Thank you for your reply.
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@BKeyport thank you for your reply. I don’t know how to power both ends of led strip. Can it be done from the same power supply? For example I should have 2 wires for 5v, 2 wires for ground and 2 wires for data and one of each must be connected to each end? If not please advice how can it be done.
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@Anthony It can be done with the same power supply. just the power and ground to be hooked up. 2 power - one to each end, 2 ground - one to each end.