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RPi + Other Software A Make-Shift Shifter?

Discussion in 'Hardware Support' started by Akriss, 17 March 2017.

  1. Akriss

    Akriss Active Member

    Messages:
    567
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    I came upon some very interesting info on how to use the first pixel in a LED strip as (for a lack of better words) a “Make-Shift Shifter”. From This page: www.elec-tron.org/?p=1184

    The page talks about using a WB2812 strip with a NodeMCU 3.3v line. However, I see no reason this would not work with a Rpi and/or a apa102c strip as well.

    A stole a pic from that sight, it details the connections. I've attached it.

    Just don't forget to separate the first and second pixels "+" line And the bit about "You then code out Pixel 0 from in your software and make sure its never activated." from that post.
     

    Attached Files:

    Last edited: 17 March 2017
  2. TPmodding

    TPmodding Administrator Staff Member Administrator

    Messages:
    1,989
    Hardware:
    RPi1/Zero, RPi2, RPi3, +Arduino, +nodeMCU/ESP8266
    yeah electron uses this often, spoke with him...he calls it "deadpixel" :) but a levelshiffter is the better option...
     
  3. Akriss

    Akriss Active Member

    Messages:
    567
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    After more research on "Deadpixel", I think I read electron's whole blog! a good read. And after some Google Fu. I came upon another variation on the "Deadpixel" found at hackaday.com/2017/01/20/cheating-at-5v-ws2812-control-to-use-a-3-3v-data-line/

    This variation does not require mapping out the first (Dead) pixel, just a diode(see pic grabbed from that sight, below). However the first pixel will be under powered.

    I found this useful info.
    Hope it helps someone here.
     

    Attached Files:

  4. penfold42

    penfold42 Active Member

    Messages:
    746
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    The second option using a diode is much safer.

    If you screw up your wiring on the 1st one you could easily kill your Pi