Raspberry Pi Zero W and through-hole LED

[jaguillette]

I'm pretty new to Raspberry Pi, but I've been trying out these through-hole LED neopixels, and I've been getting some strange results. I'm working on a breadboard, and have my power rail hooked up to pin 2 (5V output), ground rail hooked up to pin 6 (ground), and the input on the first LED hooked up to pin 12 (GPIO18). (I'm using this diagram as a reference)

I've written a test script to see if I can get the lights to do what I expect, and haven't had any luck with either SK6812_STRIP or SK6812W_STRIP as the LED_STRIP. Here it is, with the behavior I expect in the print statements, and the behavior that I'm getting in the comments:

import time
from neopixel import *

# LED strip configuration:
LED_COUNT      = 5       # Number of LED pixels.
LED_PIN        = 18      # GPIO pin connected to the pixels (18 uses PWM!).
#LED_PIN        = 10      # GPIO pin connected to the pixels (10 uses SPI /dev/spidev0.0).
LED_FREQ_HZ    = 800000  # LED signal frequency in hertz (usually 800khz)
LED_DMA        = 10      # DMA channel to use for generating signal (try 10)
LED_BRIGHTNESS = 255     # Set to 0 for darkest and 255 for brightest
LED_INVERT     = False   # True to invert the signal (when using NPN transistor level shift)
LED_CHANNEL    = 0       # set to '1' for GPIOs 13, 19, 41, 45 or 53+
LED_STRIP      = ws.SK6812_STRIP

strip = Adafruit_NeoPixel(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS, LED_CHANNEL, LED_STRIP)

rLED = Color(255,0,0)
bLED = Color(0,255,0)
gLED = Color(0,0,255)

def allOne(strip, color):
    for i in range(strip.numPixels()):
        strip.setPixelColor(i,color)
    strip.show()
    return 0

strip.begin()

strip.setPixelColor(0,rLED)
strip.show()
print("RED LED 0")
# SK6812_STRIP, SK6812W_STRIP: LED 1 is red, LED 0 is off
time.sleep(5)

strip.setPixelColor(0,bLED)
strip.show()
print("BLUE LED 0")
# SK6812_STRIP: LED 0 is blue
time.sleep(5)

strip.setPixelColor(0,gLED)
strip.show()
print("GREEN LED 0")
# SK6812_STRIP: LED 1 is green, LED 0 is off
time.sleep(5)

allOne(strip,rLED)
print("RED LIGHTS")
# SK6812_STRIP: all red, but LED 0 off
# SK6812W_STRIP: 0:off 1:red 2:green 3:blue 4:off
time.sleep(5)

allOne(strip,bLED)
print("BLUE LIGHTS")
# SK6812_STRIP: all blue
# SK6812W_STRIP: 0:blue 1:off 2:red 3:green 4:blue
time.sleep(5)

allOne(strip,gLED)
print("GREEN LIGHTS")
# SK6812_STRIP: all green, but LED 0 off
# SK6812W_STRIP: 0:off 1:green 2:blue 3:off 4:red

(edited this code when I realized I wasn't including the LED_STRIP parameter when creating my strip object, oops)

I seem to be experiencing some slightly different behavior from what's mentioned in issue #198, but that was the most similar issue that I could find. I have a blacklist file at /etc/modprobe.d/snd-blacklist.conf that just contains blacklist snd_bcm2835, and I also have both of the following lines in my /boot/config.txt file:

hdmi_force_hotplug=1
hdmi_force_edid_audio=1

I'd appreciate any suggestions! I've been trying different LED_STRIP settings to no avail, but if I find one that works I'll post back here.

[penfold42]

You need a level shifter.

Got a spare diode ? Put it in series with 5v power to the leds

[jaguillette]

Ah, that seems to have done the trick! I didn't have a pile of diodes yet, so I got one. I'm getting a bit of flickering on the rainbow effects in strandtest.py, but I think I'll be able to tweak that somehow. I also got a level shifting chip from adafruit that I haven't tried yet, but which should also help. Thanks!