Raspberry Pi + KY040 Rotary Encoder (+ S/W Volume Control)

RotaryEncoder.py

#!/usr/local/bin/python

import RPi.GPIO as GPIO

class RotaryEncoder:

	DIRECTION_CLOCKWISE = 1
	DIRECTION_COUNTERCLOCKWISE = 3
	
	prv_seq = 0
	direction = 0
	
	def __init__(self, pinA, pinB, button, callback):
		self.pinA = pinA
		self.pinB = pinB
		self.button = button
		self.callback = callback
		
		GPIO.setup(self.pinA, GPIO.IN, pull_up_down=GPIO.PUD_UP)
		GPIO.setup(self.pinB, GPIO.IN, pull_up_down=GPIO.PUD_UP)
		GPIO.setup(self.button, GPIO.IN, pull_up_down=GPIO.PUD_UP)
		
		GPIO.add_event_detect(self.pinA, GPIO.FALLING, callback=self.evt)
		GPIO.add_event_detect(self.pinB, GPIO.FALLING, callback=self.evt)
		
	def evt(self, channel):		
		a = GPIO.input(self.pinA)
		b = GPIO.input(self.pinB)
		c = a ^ b
		seq = c | b << 1
		delta = (seq - self.prv_seq) % 4
		
		if delta == 1:
			if self.direction == self.DIRECTION_CLOCKWISE:
				self.callback(self.DIRECTION_CLOCKWISE, self.button_press())
			else:
				self.direction = self.DIRECTION_CLOCKWISE
		elif delta == 2:
			if self.direction == self.DIRECTION_CLOCKWISE:
				self.callback(self.DIRECTION_CLOCKWISE, self.button_press())
			elif self.direction == self.DIRECTION_COUNTERCLOCKWISE:
				self.callback(self.DIRECTION_COUNTERCLOCKWISE, self.button_press())
		elif delta == 3:
			if self.direction == self.DIRECTION_COUNTERCLOCKWISE:
				self.callback(self.DIRECTION_COUNTERCLOCKWISE, self.button_press())
			else:
				self.direction = self.DIRECTION_COUNTERCLOCKWISE
		
		self.prv_seq = seq
		
	def button_press(self):
		return GPIO.input(self.button) == GPIO.LOW

RotaryEncoderDemo.py

#!/usr/local/bin/python

# KY040 Rotary Encoder + Raspberry Pi (Model A+)
# ===
# + (5V) e.g. GPIO.BOARD 2
# BTN is on GPIO.BOARD 12
# GND e.g. GPIO.BOARD 14
# B (DT) is on GPIO.BOARD 16
# A (CLK) is on GPIO.BOARD 18

import sys
import time
import RPi.GPIO as GPIO
from RotaryEncoder import RotaryEncoder

# (!) use BOARD NRs for PINs
GPIO.setmode(GPIO.BOARD)
GPIO.setwarnings(False)

def main_loop():
    while True:
        time.sleep(0.5)

def callback(direction, btn_pressed):
	if direction == RotaryEncoder.DIRECTION_CLOCKWISE and not btn_pressed:
		print 'CLOCKWISE'
	elif direction == RotaryEncoder.DIRECTION_COUNTERCLOCKWISE and not btn_pressed:
		print 'COUNTERCLOCKWISE'
	elif direction == RotaryEncoder.DIRECTION_CLOCKWISE and btn_pressed:
		print 'CLOCKWISE + BUTTON'
	elif direction == RotaryEncoder.DIRECTION_COUNTERCLOCKWISE and btn_pressed:
		print 'COUNTERCLOCKWISE + BUTTON'
		
if __name__ == '__main__':
	try:
		enc = RotaryEncoder(18, 16, 12, callback)
		print "listening..."
		main_loop()
	except KeyboardInterrupt:
		print >> sys.stderr, '\nExiting by user request.\n'
		sys.exit(0)

RotaryEncoderVolumeControl

#!/usr/local/bin/python

# depends on: http://pyalsaaudio.sourceforge.net
# sudo apt-get install python-alsaaudio

# KY040 Rotary Encoder + Raspberry Pi (model A+)
# ===
# + (5V) e.g. GPIO.BOARD 2
# BTN is on GPIO.BOARD 12
# GND e.g. GPIO.BOARD 14
# B (DT) is on GPIO.BOARD 16
# A (CLK) is on GPIO.BOARD 18

import sys
import time
import alsaaudio
import RPi.GPIO as GPIO
from RotaryEncoder import RotaryEncoder

# (!) use BOARD NRs for PINs
GPIO.setmode(GPIO.BOARD)
GPIO.setwarnings(False)

class Volume:

	def __init__(self):
		self.mixer = alsaaudio.Mixer(control='PCM')
	
	def get_volume(self):
		return self.mixer.getvolume('playback')[0]

	def set_volume(self, percentage):
		if percentage < 0:
			percentage = 0
		elif percentage > 100:
			percentage = 100
		
		self.mixer.setvolume(percentage)
		time.sleep(.2)
	
	def volume_up(self):
		self.set_volume(self.get_volume() + 5)
		
	def volume_down(self):
		self.set_volume(self.get_volume() - 5)
		
	def callback(self, direction, btn_pressed):
		if direction == RotaryEncoder.DIRECTION_CLOCKWISE:
			self.volume_up()
		elif direction == RotaryEncoder.DIRECTION_COUNTERCLOCKWISE:
			self.volume_down()
	
def main_loop():
    while True:
        time.sleep(0.5)
		
if __name__ == '__main__':
	try:
		vol = Volume()
		enc = RotaryEncoder(18, 16, 12, vol.callback)
		main_loop()
	except KeyboardInterrupt:
		print >> sys.stderr, '\nExiting by user request.\n'
		sys.exit(0)