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RPI4 Power question

Discussion in 'Hyperion General' started by mahican, 30 December 2020.

  1. mahican

    mahican New Member

    Messages:
    5
    Hi, I'm struggling to understand an issue I'm having.

    My original setup was an RPI4, which both powered and controlled a strip of WS2812's (30 leds/m).

    My RPI4 power cable is 5V 3A output.

    Even though in Hyperion, my estimated power draw for the LED's was around 8A (my power supply is only 3A) everything was working perfectly at maximum brightness.

    Because I was unhappy with the white colour from the WS2812's, I ordered some SK6812 RGBW and I also decided to get the 60 leds/m. I figured I'd need a dedicated power supply so I ordered a 5V 10A one as well.

    So today I've connected to new strip up with the new power supply.....however I've got an issue where the leds are flashing. Weirdly this only seems to happen when the leds are set to colour red, and over 80% brightness.

    I'm pretty sure the issue is the power supply not being enough, as when I reduce the number of leds in the layout to a point where it says the power draw will be just under 10A (which is the same as my power supply) everything starts working ok. Also when I turn the brightness down to 50% all led's work without flashing.

    So my question is, if it is indeed the case that my power supply is not enough for these leds, how on earth was my RPI4 managing to power supposedly 8A worth of leds from a 3A power supply???

    Is my issue actually the power supply?

    My current wiring with the new leds is:

    LED +5V ---> POWER SUPPLY DC JACK +TERMINAL
    LED GROUND ----> POWER SUPPLY DC JACK -TERMINAL
    LED DATA ----> RPI4 GPIO18 PIN
    RPI4 GROUND ----> POWER DC JACK -TERMINAL

    Is this right? Should I be connecting the data wire to the RPI4 SPI out instead? Because currently in Hyperion the controller is set to WS281X under led hardware....the RPI SPI option for SK6812 does not work.r

    Sorry for the long post.....
     
  2. jeroen warmerdam

    jeroen warmerdam Raspberry 3B / APA102 / Hyperion.NG relaisbox

    Messages:
    393
    Hardware:
    RPi3


    goodluck :)
     
    Last edited: 30 December 2020
    • Like Like x 1
  3. mahican

    mahican New Member

    Messages:
    5
    Thanks for the reply

    Turns out the issue was a dodgy corner connector, seems to be running ok now.

    There is still a small issue of the final section of leds at the end of the strip are flickering a small amount (they are still displaying correct colour and everything just very faintly flickering)

    I think this is because I am only powering the strip from one end.

    So I tried to connect the other end of the strip to the same barrel connector that is currently powering the beginning:

    LED +5V ---> DC JACK +TERMINAL
    LED GROUND ----> DC JACK -TERMINAL

    So my the positive terminal of the barrel connector had 2 cables powering either end of the strip, and the negative terminal had 3 cables, 2 going to the ground of the led strips either end, the finally the last cable going to the ground on the RPI4. The data wire goes from the beginning of the strip to the RPI4 with a resistor inbetween.

    However when I powered it up. nothing lit up and the power supply barrel connector got extremely hot and broke. It probably would have melted had I left it connected for more than 10 seconds. Any idea what I did wrong? How exactly are you meant to power the end of the strip from the same power supply?
     
  4. mahican

    mahican New Member

    Messages:
    5
    This is exactly how it was wired before. And it was working albeit w ith the final section faintly flickering.

    [​IMG]

    Below is how I wired the end of the strip which subsequently superheated and broke the dc jack. Anything obviously wrong? Apart from the crude drawing...

    Hardware_-_Raspberry_Pi_2_40_Pin_Connection_to_ws2812b.png
     
  5. mahican

    mahican New Member

    Messages:
    5
    https://photos.app.goo.gl/7oPGrs1qMYAicj8Q6

    Here is a video of the flickering, if you look closely you can see its mainly at the bottom which is the end of the strip, and on the left side it is not really noticeable as that is the beginning of the strip
     
  6. jeroen warmerdam

    jeroen warmerdam Raspberry 3B / APA102 / Hyperion.NG relaisbox

    Messages:
    393
    Hardware:
    RPi3
    Strange, because layout is good. Probably ground isn't good or wrong connection
     
    Last edited: 31 December 2020
  7. mahican

    mahican New Member

    Messages:
    5
    Ahh could be, I am using jumper cables and just shoved all 3 ground connections into the barrel so maybe one of them wasn't seated properly. I'll try again tomorrow, thanks for your help