main.py

# Trinket IO demo
# Welcome to CircuitPython 3.1.1 :)

import board
from digitalio import DigitalInOut, Direction, Pull
from analogio import AnalogOut, AnalogIn
import touchio
import time

import adafruit_dotstar as dotstar
# One pixel connected internally!
dot = dotstar.DotStar(board.APA102_SCK, board.APA102_MOSI, 1, brightness=0)
dot[0] = (0,0,0)

# Analog output on D1
aout = AnalogOut(board.D1)

# Capacitive touch on D3
touch = touchio.TouchIn(board.D3)

# extra ground for motor board
motorGnd = DigitalInOut(board.D0)
motorGnd.direction = Direction.OUTPUT
motorGnd.value = 0

#print("STARTING PURRTY CAT")

PURR_INCREMENT = 25
PURR_DECREMENT = 200
PURR_MINIMUM   = 175*256
PURR_MAXIMUM   = 185*256  # must have space for 16 bit value
purrValue = 0
while True:
  if touch.value:
    if purrValue < PURR_MINIMUM:
      purrValue = PURR_MINIMUM
    purrValue += PURR_INCREMENT
  else: 
    purrValue -= PURR_DECREMENT

  if purrValue < 0: purrValue = 0

  if purrValue > PURR_MAXIMUM: purrValue = PURR_MAXIMUM    

  # set analog output to 0-3.3V (0-65535 in increments)
  aout.value = purrValue
#  print("Touch {} , Purr {}".format(touch.raw_value, purrValue/256))
  time.sleep(0.1) # make bigger to slow down

#print("EXITING PURRTY CAT")