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2.Colourful Light Strip

Project Introduction¶

In this part, we will use an external light strips to achieve red, orange, yellow, green, blue, and purple colors. UNIHIKER is equipped with a microcontroller responsible for controlling onboard components and GPIO.

Based on this functionality, we can control the external light strips by Pin21. This project uses the np = NeoPixel(Pin(NEOPIXEL_PIN), PIXELS_NUM) method in the PinPong library of Python to control a NeoPixel LED externally connected through side pins of the board. Here is an example of controlling the NeoPixel LED to blink.

Hardware Required¶

Code¶

In this example, the UNIHIKER is first initialized with Board().begin(). Then, we use NEOPIXEL_PIN = Pin.P21 to initialize the pin. To define the number of lights, we use PIXELS_NUM = 7. Finally, we use np = NeoPixel(Pin(NEOPIXEL_PIN), PIXELS_NUM) to initialize the NeoPixel.

In the main loop, we use the np[0] = (0, 255 ,0) function to change the color of the lights. We can also use the np.rainbow(0,7,0,0x0022FF) function to display a rainbow pattern. To achieve the desired results, two loops can be used to change the color of the lights and to turn them off sequentially.

# -*- coding: utf-8 -*-

# Experimental effect: Control WS2812 single line RGB LED light
# Wiring: Use a computer to connect a UNIHIKER, and connect the ws2812 light to the p21 port
import time
from pinpong.board import Board,Pin,NeoPixel

NEOPIXEL_PIN = Pin.P21
PIXELS_NUM = 7  # number of lights

Board("UNIHIKER").begin()  # Initialize, select board type, do not input board type for automatic recognition

np = NeoPixel(Pin(NEOPIXEL_PIN), PIXELS_NUM)
np.brightness(128) #0~255

while True:
  np[0] = (0, 255 ,0)  # Set the RGB color of the first light
  np[1] = (255, 0, 0)  # Set the RGB color of the second light
  np[2] = (0, 0, 255)  # Set the RGB color of the third light
  np[3] = (255, 0, 255)  # Set the RGB color of the forth light
  np[4] = (255, 255, 0)  # Set the RGB color of the fifth light
  np[5] = (0, 255, 255)  # Set the RGB color of the sixth light
  np[6] = (255, 255, 255) # Set the RGB color of the seventh light
  time.sleep(1)

  np.rainbow(0,7,0,0x0022FF)  # Display the light strip in the form of a rainbow
  time.sleep(1)

  for i in range(7):
    np.rotate(1)  # Cycle to change the color of the light a beads
    time.sleep(1)

  for i in range(7):
    np.shift(1)  # Turn off the light beads in sequence
    time.sleep(1)

  np.clear()
  time.sleep(1)

Demo Effect¶