butterfly-example.py

#!/usr/bin/env python3
########################################################################
# Filename    : butterfly.py
# Description : Check for unread love notes and control a mechanical butterfly
# Author      : JFining
########################################################################
import RPi.GPIO as GPIO
from time import sleep
import requests
import json

butterflyPin = 11    # define the GPIO pin that controls the transistor
API_GW_URL = ""

def setup():
	print ('Program is starting...')
	GPIO.setmode(GPIO.BOARD)       # Numbers GPIOs by physical location
	GPIO.setup(butterflyPin, GPIO.OUT)   # Set transistor control pin mode to output

def butterfly_high(duration):
	GPIO.output(butterflyPin, GPIO.HIGH)
	sleep(duration)

def butterfly_low(duration):
	GPIO.output(butterflyPin, GPIO.LOW)
	sleep(duration)

def pulse_to_on(total_time_on):
	current_duration = 0
	on_time = .0002
	off_time = .00035
	decay_factor = 2
	on_decayed = on_time
	off_decayed = off_time
	while current_duration < total_time_on:
		butterfly_high(on_decayed)
		butterfly_low(off_decayed)
		current_duration += on_decayed + off_decayed
		on_decayed = on_time * (decay_factor ** (-1.2 * current_duration))
		off_decayed = off_time * (decay_factor ** current_duration)

def flap_n_times(n):
	flap_count = 0
	while flap_count < n:
		pulse_to_on(2)
		butterfly_low(8)
		flap_count += 1

def un_dynamo_note(note):
	new_obj = {}
	for key in note:
		new_obj[key] = note[key]['S']
	return new_obj

def get_all_notes():
	response = requests.request("GET", API_GW_URL)
	items = json.loads(response.text)["Items"]
	notes = []
	for item in items:
		notes.append(un_dynamo_note(item))
	return notes

def find_unread(notes):
	for note in notes:
		# Return True if we find a note that is not acknowledged
		if note["ack"] == 'false':
			return True
	return False

def destroy():
	print("Destroying resources, stopping script.")
	GPIO.output(butterflyPin, GPIO.LOW)     # butterfly off
	GPIO.cleanup()                     # Release resource

if __name__ == '__main__':
	setup()
	try:
		while(True):
			notes = get_all_notes()
			if (find_unread(notes)):
				flap_n_times(5)
			sleep(60)
	except KeyboardInterrupt:  # When 'Ctrl+C' is pressed, destroy() will clean up
		destroy()
	except Exception as e: # Just in case anything goes wrong unexpectedly, turn off!
		print(e)
		destroy()