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RPi + OpenELEC Flickering LEDs only with external grabber / Videos attatched

Discussion in 'Software Support' started by Manuel, 19 October 2018.

  1. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Hello Guys,

    I have some problems with my ambilight system. Some of the LEDs are flickering in different colours. The problem occurs only when I want to control the LEDs with an external grabber (eg. HDMI device). When I am starting a video on openelec (using internal grabber) then the problem does not occur.

    2 videos which should show the problem:




    It looks like some LEDs can't decide which colour they want to show. The majority of the LEDs are getting controlled correctly but some not. This problem also occurs when the video is not getting played.

    I am using the following things:
    -
    Openelec (8.0.4)
    - RPI3
    - WS2801 RGB LED-Stripe
    - USB Video grabber: https://www.amazon.de/gp/product/B0...tiveASIN=B0013BXFLG&linkCode=as2&tag=pow07-21
    - HDMI 2 AV converter: https://www.amazon.de/gp/product/B0...tiveASIN=B01AG0MDY4&linkCode=as2&tag=pow07-21
    - HDMI splitter: https://www.amazon.de/gp/product/B0...tiveASIN=B01615JA3A&linkCode=as2&tag=pow07-21

    Attatched you can find:
    - Screenshot of grabbed picture for external grabber
    - Hyperion.json.config
    - blueprint of the connection (from Powerpi.de)

    I did use the german tutorial of powerpi.de to create my ambilight with the RPI.

    I really hope some of you genius guys can help me out.

    BR

    Manuel
     

    Attached Files:

    Last edited: 19 October 2018
  2. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
  3. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Hello Akriss,

    thanks for your reply. I only have this problem when I am controlling the LEDs with an external grabber not when I am playing a video via Kodi. I did read a few things to use aluminium foil to protect the data cabes. But this did not work. The problem stays the same. Attatched a few pictures of my ambilight system. I will buy ferrite beads. Where do I need to put these? On which cables? Also on the HDMI cables?

    Thanks in advance.

    BR

    Manuel
     
  4. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    Some where on the led data lines (white,white,orange/red,blue,black) on the two power lines as well (red,red). Both lines on the grabber, could clean the signal up. It couldn't hurt on the hdmi as well.

    However the level shifter is really better, as it increases the signal to the leds to 5v. the Rpi only sends a 3.3v signal. Short runs/ less leds often get away with a 3.3 v signal. Longer runs/more leds tend to need a signal boost. And a better signal can often overcome interference.

    Hope it helps.
     
  5. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Hello Akriss,

    thanks for your reply. Do I need 1 ferrite bead per line or do I need 1 on every end (2 per line). And can I put more cables into one ferrite bead (eg. 3 Data lines into one ferrite bead)? Just to know how many ferrite beads I need... Can you send me an example of what kind of ferrite bead I need to buy?

    Is there any tutorial for the level shifter and how to install it? Because I don't know what it is and for what it is good for...

    Thank you very much. :)

    BR

    Manuel

    EDIT:
    Maybe another good information:
    - The PI doesn't has his own power suply. It is getting power from the silver general power suply (where the LEDs are also connected)
    - When I am using the hyperion App and the effects of it. I do not get the error.
     
    Last edited: 21 October 2018
  6. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    If you can bundle together all the wires from the led strip(white,white,orange/red,blue,black and the two red), one should be fine there. Generally it one bead per bundle of wires. So one per hdmi, if needed. However the grabber may benefit with both end having a bead, since you have a short usb cable between it and the Rpi.

    Edit: you can get a pack from ebay or amazon and put one on all the cables. Ferrite beads are very cheap. Something like: www.amazon.com/eBoot-Pieces-Ferrite-Suppressor-Diameter/dp/B01E5E5IY4

    However I reiterate, a level shifter it is a better solution as is boosts the signal level from 3.3v to 5v.

    If your soldering skills are rusty, there is a p̶r̶e̶ ̶m̶a̶d̶e̶ some soldering required level shifter I came upon (haven't tried yet) that I think will work with your led's (https://www.tindie.com/products/ManiacalLabs/pipixel-raspberry-pi-led-strip-hat/) might want to check with the seller first to make sure it's ok for use with WS2801 led's.

    edit: Some lite reading on logic level shifters/converters here: https://core-electronics.com.au/tutorials/logic-level-converters-for-raspberry-pi.html

    Hope it helps.
     
    Last edited: 22 October 2018
  7. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Hello Akriss,

    thanks for your help. :)

    I don't want to use the "pre-made" level shifter, due to the shipping costs (around 20 euros to germany). I also did read, that the level shifter is only needed, if the problem occurs when the LEDs are displaying a very bright color. My problem occurs, when pretty dark scenes are displayed. On bright scenes there is almost no problem. What do you think about this?

    If I want to "build" the level shifter by my own... What kind of components do I need? On the website you mentioned (core-electronics.com) is a grey thing displayed where the level shifter is attached to, what is this? I already searched for a good tutorial for installing the level shifter, but I didn't find one. Maybe you can provide me with this information? With electrical stuff i am pretty bad (newbie).

    How can you explain that the problem only occurs when the external grabber is getting used? When I am controlling the LEDs with the APP or with Kodi, than the problem does not come up.
    Do you think the problem comes from electrical interference (maybe from other devices)?

    Thank you very much! :)

    Best greetings from Germany.

    Manuel

    EDIT: I did take another video. Maybe this is better to see the problem. In the video you can see at the top the "flickering" it is more like a blazing flame effect:


    Thanks
     
    Last edited: 22 October 2018
  8. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    hmm. yes this could be interference on the HDMI cables, or a noisy power supply. Ferrite beads can help with that interference as well, on the hdmi and the DC side of the power supply.

    You can copy the that pre made one as the maker/seller has All the needed info to make your own on Github. https://github.com/ManiacalLabs/PiPixel, Even the PCB files are there to make the circuit board! However, there is some other info on the boards here on making your own. You need to search a bit,

    However, you can use the other type of level shifter as described here: https://hyperion-project.org/wiki/using-level-shifter. There is info on the boards here scattered about that type of level shifter. I have never used that type, so I'm not sure on the hookups.

    Yes this can point to interference in the HDMI/grabber/AV2hdmi cabling.

    If in doubt, Put a ferrite bead on the cable. that's exactly the purpose of a ferrite bead.


    Reference links worth the read:
    https://raspberrypi.stackexchange.com/questions/9642/control-ws2801-with-raspberry-pi
    https://hyperion-project.org/wiki/Supported-hardware
    https://forum.arduino.cc/index.php?topic=341440.0
    https://hyperion-project.org/threads/faulty-led-stripe-please-help.887/page-2#post-11932
    https://www.google.com/search?q=74ahct125+wiring&tbm=isch

    PS: I think there is a EU seller of that pre made board: https://hackerspaceshop.com/collections/ambipi-tv/products/ambipi-tv

    Hope it helps.
     
  9. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Hello Akriss,

    sorry for tha late reply. I was on the road the last few days.

    I did order some ferrite beads and did add them to the ambilight system (about 10 pieces). Unfortunatelly it didnt get better. The problem stays the same. But I noticed, that while the LEDs are showing the colors and I unplug the grabber from the pi (USB Connection), the LEDs stop flickering. Due to unplugging, the LEDs are not getting any new signal and so they arent changing the color. But the flickering stopps. Do you think it helps to replace the grabber?

    I also did unplug nearly any other device, to be sure the interference is not comming from others.

    What would be your next steps to fix this problem?

    Thanks for your help!

    BR

    Manuel

    EDIT:
    Can you recommend a grabber? I really want to test, if its better with a new grabber.
     
    Last edited: 27 October 2018
  10. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    I can't recommend any particular grabber or HDMI2AV. All the inexpensive hardware from china, it's all seems to be hit and miss.

    I bought four UTV007 grabber's from a china seller and what I received was two working UTV007 and two (defective?) unknown chips that the system did not detect. And upon opening the case's, very different innards from the working one . But at <8$ each, shipped. I'm not complaining much.

    I've been trying to find a grabber with STK1160 chip, So far I have ordered from three different (advertised as STK1160) aliexpress sellers, all contained UTV007 chips (none better or worse then the others) . I have two more on order, hopefully I receive STK1160 chip's. Fingers crossed.

    I have noticed that some HDMI2AV converters are just plain crap. I found more then a handful with offset pictures, where the bottom and left of picture was cut off and/or pushed over. And some just with horrible color representation or just plain bad pictures.

    My led's do blink as well when a static picture is shown. It not as pronounced as the blinking you are seeing. Probably because My TV's are about 14cm away from the wall. Yours look to be -/+8cm

    Running out of ideas. Possibly shielded wiring, With the shielding attached to ground. Other then building a Faraday cage around it that is =)

    You tried the level shifter option yet? If the signal being sent to the led's was stronger It tends to over power the interference.

    P.S. there is another grabber I have my eye on. However it's x10 more $$. from www.febon.net/products (www.febon.net/products/usb20-febon100-uvc-cvbs-composite-capture-card)
     
    Last edited: 27 October 2018
  11. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Hello Akriss,

    I will try to use a Cat6 cable for the Dataline from the Pi to the LED stripe. Do you think I should use for Powersuply to LED Stripe also CAT6 cables?

    I did not try the level shifter option yet. I think its kind to hard for me to build it..

    BR

    Manuel
     
  12. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    You can try. Network cable is not meant to carry a lot of amperage so you should double (or triple) up the wires for power.
     
  13. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    What kind of shielded wiring did you mean? I thought you meant network cables?

    The strange thing is, that the whole ambilight system already worked for me... It just had problems with the soldingering points. Thats why I didn't use the ambilight for about 4 Months. Now after fixing the "soldering problem" I have the problem with the flickering LEDs (only with external Grabber).
    All I did was:
    - Removing 4 LEDs (cut them off)
    - Soldering the beginning of the new LED (Dataline and powerline)

    The devices stayed the same.
    Before those changes, the ambilight was totally fine wether with the internal or external grabber. Both worked...

    Do you preclude settings in the hyperion config or any other software?

    Thanks!

    BR

    Manuel

    EDIT: And after the old problem I used the newest Openelec.
    EDIT2: I did add a screenshot of the grabbed picture from Hypercon.jar
    I think the colourful lines maybe a problem?
     

    Attached Files:

    Last edited: 30 October 2018
  14. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    I found some heavy gauge shielded 4 wire cable that worked well. It used 16, maybe 18 gauge wire, If I remember correctly. Network cable is usually 24 gauge wire (larger number gauge = thinner wire, ) Network cable can work, just need to be mindful of the wires capacity to handle currants.

    No. Just a normal setup.

    Bingo! . .That is almost certainly interference. I think that is the cause of the flickering, as well. Defective in some way perhaps?
     
  15. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Can you send a link of this kind of cables?
    And how do I need to connect them from PI <-> LED Stripe? Currently I am using jumper cables.

    I did buy the exact same grabber again and replaced it yesterday, but the problem stays the same. I did buy this one:
    https://www.amazon.de/LogiLink-Audi...d=1540987685&sr=8-1&keywords=logilink+grabber

    Do you think the problem can come from the HDMI splitter or Video Audio AV converter? Both need extra power supply and are not working without.

    It feels like we are coming closer to the solution...

    Thanks

    BR

    Manuel
     
  16. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    This type, ( https://www.mouser.com/Wire-Cable/M...or-Cables/_/N-9ms9i?P=1ytityuZ1z0t1rpZ1yx79kq )
    It has four wires w/shield. I found a local shop selling the cable by the meter.
    One wire for positive and one wire And the shielding for ground (shielding should only be tied to ground on one end of the wire and open on other end. Don't ask why. That's the advise given to me and the answer is long and requires lots of reading about Ground_loop ) Also one wire for data and one wire for clock.

    Maybe. Cheaply made inexpensive components equals uncertainty. I've returned more then a few splitters and hdmi2av components that did not work or where problematic. However that said some can work well.


    Hope it's helping.
     
  17. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    Hello Akriss,

    I did replace the Grabber and the Converter and it didn't solve the problem unfortunatelly. I am glueless at the moment...

    Thanks
     
  18. Akriss

    Akriss Active Member

    Messages:
    377
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    it's defiantly interference from some other device. From what is the question.

    That screenshot of the interference reminded me of when I used an antenna to receive tv and my microwave oven (when on) would show a very similar type of interference.

    Could be interference from the tv. Try a test by moving the Rpi, grabber, hdmi2av, power supply and wires off the back of the tv and a small distance away (also from other equipment). Leaving just the led's on the back.
     
  19. Daniyal

    Daniyal New Member

    Messages:
    2
    Hardware:
    RPi1/Zero, +Arduino, +nodeMCU/ESP8266
    Hello! I am experiencing the same colour flickering problem with my LEDs, the screenshot from grabber looks awful as well. Have you found any solutions?
     
  20. Manuel

    Manuel New Member

    Messages:
    11
    Hardware:
    RPi3
    I already tried this and did run the ambilight without a TV power connection. So the TV was not able to make the inteference.
    I wil try this again - I will plug out any not needed device except the Pi, Grabber, LEDs, Converter and splitter.

    @Daniyal: Unfortunatelly not - Problem still there.
    But I would be thankful if you also would help us here :)


    EDIT:
    I did now unplug everything (except Power Supply, LEDs, Pi, Grabber and Converter). Still flickering.
    I did connect the external HDMI device directly to the converter without the splitter - Problem stays the same. I also did replace the external HDMI source.

    More and more I think, the interference is comming from the power supply..
    -> Nope, I thought about this idea, but the flickering does not occur when internal grabber (when Kodi is displayed) is used.. So it needs to be something between the Pi and the converter. Or am I wrong?
     
    Last edited: 8 November 2018