cycle456-potentiometer-based-timing.py

#!/usr/bin/env python3

from time import sleep
from gpiozero import LED
from ADCDevice import ADS7830
from threading import Thread

red = LED(4)
green = LED(5)
blue = LED(6)
adc = ADS7830()

# ADS7830 is an 8-bit analog-to-digital converter,
# The possible values I can get from the analog input is 0-255.
# Sometimes it reads as 1 when the potentiometer is turned completely down,
#   so I'm using min_a_value=1 to set a higher threshold
min_a_value = 1
max_a_value = 255

# a_value will be the value from the analog input
a_value = 0

# I'm using separate threads to handle the analog input and LED outputs

class PThread(Thread):
    def run(self):
        # a_value is not accessible within thread without using global
        global a_value
        while True:
            a_value = adc.analogRead(0)
            sleep(0.05)

class LThread(Thread):
    def run(self):
        # a_value is not accessible within thread without using global
        global a_value

        # using c to count 1-100
        c = 1

        # using x to count 0-5
        # LEDs will light up indicating the value of x as shown in this table:
        #
        # x | red | grn | blu
        # --------------------
        # 0 | off | off | on
        # 1 | off | on  | on
        # 2 | on  | on  | on
        # 3 | on  | on  | off
        # 4 | on  | off | off
        # 5 | off | off | off
        #
        x = 0

        while True:
            # LEDs will not cycle if potentiometer is turned all the way down
            if a_value > min_a_value:
                # zzz_ms is the number of milliseconds between LED cycles
                # possible values are 0-100
                zzz_ms = int((1 - (a_value / max_a_value)) * 100)
                # setting a minimum of 3ms
                if zzz_ms < 3: zzz_ms = 3
                # if c divided by zzz_ms has no remainder,
                # LEDs will cycle according to the value of x in table above
                if c % zzz_ms is 0:
                    blue.on() if x < 3 else blue.off()
                    green.on() if 0 < x < 4 else green.off()
                    red.on() if 1 < x < 5 else red.off()
                    # increment x
                    x += 1
                # reset x counter at 6
                if x > 5: x = 0
            # increment c
            c += 1
            # reset c counter at 101
            if c > 100: c = 1
            # sleep for 1ms
            sleep(0.01)

PThread().start()
LThread().start()

cycle456-potentiometer-based-timing.svg