This example brings together LEDs, button input, and a servo all operating at the same time without interfering with one another.

When you press the button it will switch to blinking the opposite pair of LEDs by swapping the dictionaries into and out of the BLINK_LIST using the pop() and append() functions.

"""
This example script shows the usage of servos, LEDs, and buttons all
used simultaneously without interrupting each other.
"""

import board
import digitalio
import time
import neopixel
import pwmio
from adafruit_motor import servo
from digitalio import DigitalInOut, Direction, Pull

btn = DigitalInOut(board.SWITCH)
btn.direction = Direction.INPUT
btn.pull = Pull.UP

prev_state = btn.value

pixels = neopixel.NeoPixel(board.NEOPIXEL, 1)
pixels[0] = (0, 0, 0)

BLINK_LIST = [
    {
        "ON": 0.5,
        "OFF": 0.5,
        "PREV_TIME": -1,
        "PIN": board.D5,
    },
    {
        "ON": 0.5,
        "OFF": 0.5,
        "PREV_TIME": -1,
        "PIN": board.D6,
    },
    {
        "ON": 0.5,
        "OFF": 0.5,
        "PREV_TIME": -1,
        "PIN": board.D9,
    },
    {
        "ON": 0.5,
        "OFF": 0.5,
        "PREV_TIME": -1,
        "PIN": board.D10,
    }
]

SERVO_LIST = [
    {
        "MAX_ANGLE": 180,
        "MIN_ANGLE": 0,
        "PREV_TIME": -1,
        "PIN": board.A1,
        "DELAY_BETWEEN": 0.05,
        "SERVO": None,
        "MOVE_BY": 5
    },
    {
        "MAX_ANGLE": 90,
        "MIN_ANGLE": 0,
        "PREV_TIME": -1,
        "PIN": board.A3,
        "DELAY_BETWEEN": 0.02,
        "SERVO": None,
        "MOVE_BY": 2
    }
]

for cur_servo in SERVO_LIST:
    pwm = pwmio.PWMOut(cur_servo["PIN"], duty_cycle=2 ** 15, frequency=50)
    # Create a servo object.
    cur_servo["SERVO"] = servo.Servo(pwm)


for led in BLINK_LIST:
    led["PIN"] = digitalio.DigitalInOut(led["PIN"])
    led["PIN"].direction = digitalio.Direction.OUTPUT

disabled_leds = []
# temporarily remove first two from the blink list
disabled_leds.append(BLINK_LIST.pop(0))
disabled_leds.append(BLINK_LIST.pop(0))
while True:
    # Store the current time to refer to later.
    now = time.monotonic()

    cur_state = btn.value
    if cur_state != prev_state:
        if not cur_state:
            print("BTN is down")

            # swap the LED Blink patterns to the opposite pairs of LEDs
            temp = []
            temp.append(BLINK_LIST.pop(0))
            temp.append(BLINK_LIST.pop(0))

            BLINK_LIST.append(disabled_leds.pop(0))
            BLINK_LIST.append(disabled_leds.pop(0))

            disabled_leds.append(temp.pop(0))
            disabled_leds.append(temp.pop(0))

        else:
            print("BTN is up")

    prev_state = cur_state

    for led in BLINK_LIST:
        if led["PIN"].value == False:
            if now >= led["PREV_TIME"] + led["OFF"]:
                led["PREV_TIME"] = now
                led["PIN"].value = True
        if led["PIN"].value == True:
            if now >= led["PREV_TIME"] + led["ON"]:
                led["PREV_TIME"] = now
                led["PIN"].value = False

    for servo in SERVO_LIST:
        if now >= servo["PREV_TIME"] + servo["DELAY_BETWEEN"]:
            try:
                servo["SERVO"].angle += servo["MOVE_BY"]
            except ValueError as e:

                if servo["MOVE_BY"] > 0:
                    servo["SERVO"].angle = servo["MAX_ANGLE"]
                else:
                    servo["SERVO"].angle = servo["MIN_ANGLE"]

            if servo["SERVO"].angle >= servo["MAX_ANGLE"] or \
                servo["SERVO"].angle <= servo["MIN_ANGLE"]:

                    servo["MOVE_BY"] = -servo["MOVE_BY"]

            servo["PREV_TIME"] = now

This guide was first published on Oct 08, 2020. It was last updated on Oct 08, 2020.

This page (All Together Now) was last updated on Apr 18, 2021.

Text editor powered by tinymce.