Skip to content

Our Seventh Lab: Using a NeoPixel Display

Parts for this Lab are in Bag 7

  1. We will use the neopixel display from Bag 7.

    • Insert the lead from GND of the display into j3
    • Insert the lead from VCC of the display into j1
    • Insert the lead from IN of the display into a1

  2. When you are finished, your breadboard should look similar to the image below (Note: your wires may be different colors)

Lab 7

Working With the NeoPixel Display

  • NeoPixels are Red-Green-Blue LEDs that are designed to makes them easy to control with three wires: GND, +5V and a single serial data line.

  • Controlling NeoPixels is challenging since the timing of data being sent must be very precise. Python alone is not fast enough to send bits out of a serial port. So a small function that uses assembly code is used. This code can be called directly from a neopixel driver library so that the user's don't need to see this code.

  • Working with the display and the library

    • Import Pin and NeoPixel from their libraries 
      1
2
      from machine import Pin
from neopixel import NeoPixel
    • Define the number of pixels, the output pin, and intialize the NeoPixel class 
      1
2
3
4
5
      NUMBER_PIXELS = 8
LED_PIN = 0

pin = Pin(LED_PIN, Pin.OUT) 
strip = NeoPixel(pin, NUMBER_PIXELS)
    • Finally, you can set any of the pixels either one at a time 
      1
2
3
      for i in range(0, NUMBER_PIXELS): 
    strip [i] = (0,0,255) 
    strip.write()
    • Or, you can set all of the pixels at the same time 
      1
2
      strip.fill(0,0,255) 
strip.write()

Challenge

Using a variety of colors, set the pixels, one at time to each color such that it appears that the display starts out with a single pixel lit in a color, then two pixels in the same color, etc. until all 8 are lit. Then start on a second color lighting the first pixel.

NeoPixel Display 

1
2
3
4
5
6
Colors can be found here: 
[https://www.rapidtables.com/web/color/RGB_Color.html](https://www.rapidtables.com/web/color/RGB_Color.html)

Once that works, turn the entire set of pixels on with a single color, then move to the next color that you selected.

 - Don't forget to comment your code!