A Python script to show a "hidden" feature of the Pimoroni Display-o-Tron HAT. Individual backlight LED control: marching hues

huemarch.py

#!/usr/bin/env python
print("""
This example shows you a feature of the Dot HAT.
You should see colors step across the screen!

Press CTRL+C to exit.
""")

import dothat.backlight as backlight
import dothat.lcd as lcd
import atexit
import time

def tidyup():
    backlight.off()
    lcd.clear()
    backlight.graph_off()

atexit.register(tidyup)
lcd.set_cursor_position(0,0)
lcd.write("the hues go marching one by one")

dVal = 0.05  # hue value delta - alter to taste
delta = dVal
hue = 0 # hue to use, range 0..1
y = 0
while True:

    rgb = backlight.hue_to_rgb(hue)

    # there are six RGB LEDs - the % (mod) operator insures range 0-5
    backlight.single_rgb(y % 6, rgb[0], rgb[1], rgb[2])

    y += 1  # next LED

    time.sleep(0.5)

    # toggle the hue "direction"
    hue += delta
    if (hue > 1.0):
        delta = -dVal
        hue = 1.0
    if (hue < 0):
        delta = dVal
        hue = 0