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X86/64 NUC + Nodemcu + WS2813

Discussion in 'Hardware Support' started by itsme2501, 23 April 2018.

  1. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Hello folks,
    After lot of reading i decided to start my thread as i do have few questions remaining before being able to finalize the setup.
    You can see enclosed a schema of my setup, right now only the "video" side is finished.
    [​IMG]

    I am now working on the Nodemcu and the LED.
    I have WS2813 LED, which has 4 wires (redundant signal data) and i have to connect it to the Nodemcu :
    [​IMG]

    This is the complicated part :
    I understand how to connect the +5V and the GND but how it is possible know which PIN of the nodemcu i have to use to connect the BO and DO ? According, to what i have already read, the DO and BO of the WS2813 is data signal and data backup signal, so there can be connected together on the same PIN.

    Thanks.
    Ps : If you question regarding the video side, feel free.
     
    Last edited: 23 April 2018
  2. Akriss

    Akriss Active Member

    Messages:
    331
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
  3. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Thanks Akriss for your answer.
    Okay, i was totally wrong, i thought i have to connect both to the same PIN because it was "active/backup" Data.
     
  4. penfold42

    penfold42 Moderator Developer

    Messages:
    742
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    You should consider a level shifter between the nodemcu and “DI”.

    The nodemcu is a 3v3 logic level but the leds specs claim it needs 0.7 * 5v = 3.5v

    I prefer 74HCT series chips rather than those cheap mosfet based shifters on eBay
     
  5. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Hi pendold42,
    To be honest i was not aware of that, after reading the datasheet of the ws2813 i undertand what you are saying.
    So i should considerer using a 74AHCT125 connected to my nodemcu logical ouput and connect the 74AHCT125 5V logical output to the WS2813.
    Using this kind of wiring method :
    [​IMG]
    It might works without it but it can can cause so weird behavior as the logical level are not going to be exactly the same on both sides (nodemcu side and ws2813 side) and it can lead to incorrect logical level on one side, is it my understanding correct ?

    Thanks again.

    EDIT : new image with the 74HCT but not nodemcu but the concept is the same.
     
    Last edited: 24 April 2018
  6. Jose Ramon Espericueta

    Jose Ramon Espericueta Member

    Messages:
    66
    Hardware:
    RPi3, +Arduino
    Hi , i have
    Hi , a question maybe you can help me , i have a level shifter SN74HCT125N http://mexico.newark.com/texas-inst...rting-buffer-dip-14/dp/68K1116?st=SN74HCT125N
    this can work or i bought an incorrect?
     
  7. Akriss

    Akriss Active Member

    Messages:
    331
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    This should help with the questions asked from both folks. I hope.
    NODE level-shifter.jpg
     
  8. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Thanks Akriss ! Do we really need to connect the 2/3/4 inputs PIN to GND as they not used at all ?

    Regarding the dual data of the WS2813, i found this : https://github.com/FastLED/FastLED/issues/374
    "For Ws2813 Both Data lines should be connected together to the same data pin on the Arduino etc. Ws2813 strip will work ok if only the DI line is connected and BI left disconnected, but in this config the first LED will not work as the chip expects the same data on both inputs. After each LED chip the BI line from the input of the first chip is directly connected to the DI input of the next chip (which is also connected to the D0 of the first chip. Therefore only one Data pin is needed to feed both inputs and is connected to both DI and BI inputs."
     
  9. Akriss

    Akriss Active Member

    Messages:
    331
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    Last edited: 25 April 2018
  10. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Thanks Akriss,
    I think i will try both as my led strip will be to longer and i another nodemcu so i will try both and compare the results.
    I think in most cases it is going to work but the best approach is to connect all pins properly.
     
  11. penfold42

    penfold42 Moderator Developer

    Messages:
    742
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    CMOS chips have a very very high input imprudence.
    Unnconnected (or “floating”) inputs act like a series of tiny antennas and cause the chip to oscillate at many MHz.
     
    Last edited: 27 April 2018
  12. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Thanks penfold42 ! Ok so lets do it properly directly..

    I am now working on the sketch on my nodemcu lua v3. (if you think it is better to open a new topic i can do it but it still hardware related).
    I found some exemples on internet so i think i will be able to figure out how to produce a fist draft sketch.
    I think i am going to use the WifiManager and NeoPixelsBus libraries.
    Regarding the sketch :
    Half of the time the baudrate is defined in the sketch and the other part of the time is not defined at all (the word baud is not present in the whole sketchfile).
    Do we need to define the baudrate, is it a good practice or it is useless as the default baudrate will be used ?

    Thanks.
     
  13. penfold42

    penfold42 Moderator Developer

    Messages:
    742
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
  14. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Thanks penfold.
    I will read it carefully, it add another choice and I have to read again to understand better.
    This is the one you are using for your ambilight system ?
    The WS2813 is not part of the led supported unfortunately.
     
  15. penfold42

    penfold42 Moderator Developer

    Messages:
    742
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
  16. Jose Ramon Espericueta

    Jose Ramon Espericueta Member

    Messages:
    66
    Hardware:
    RPi3, +Arduino
    Thanks for your help, a question i want to use a nodemcu over wifi i read about hyperion second instance, i have Ws2812b leds strip , wich the correct or Last code for nodemcu ?
     
  17. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Thanks Penfold !
    I will try to do the same thing as you.
    I have successfully installed all libraries and plugins needed to compile and then upload the files needed.
    Before uploading it, can you confirm that this is supported to work on the Nodemcu lua ?( i saw ESP8266 and also ESP01 on the documentation).
    Last but least, i saw that it is possible to define the WIFI parameters in the sketch but nothing about how to set up the led used (ws2812, ws2813 and so son) and how to define the PIN that should be used to control the led.
    May i miss something.

    Thanks.
     
  18. penfold42

    penfold42 Moderator Developer

    Messages:
    742
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    Yep - nodemcu is fine.
    Esp8266 is the micro controller used on a variety of boards.

    Nodemcu, esp-01, esp-12, Wemos d1 are just some of the boards out there.

    GPIO 2 is the pin used for the leds.

    When it’s working, you point a browser at it to configure the number of leds and the led type. Use ws2811 (it’s the same as 2813 but with a shorter reset pulse which was altered to cater for the 2813)
     
  19. penfold42

    penfold42 Moderator Developer

    Messages:
    742
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    With espixelstick ? Any code - the 2812 has been supported forever
     
  20. itsme2501

    itsme2501 New Member

    Messages:
    28
    Hardware:
    +nodeMCU/ESP8266
    Thanks again!
    I was reading and found many answers to my questions on the github issues page (answers from you also) and I wanted to edit my post with this new findings but you answered too fast, with additional clarifications, thanks !
    So it's perfect I will flash my nodemcu and follow the steps and share the result.
     
    Last edited: 1 May 2018