add square and linear modes to blinkenlights

blinkenLights.py

@@ -3,7 +3,7 @@ Controls an LED using a GPIO pin
 '''
 import RPi.GPIO as GPIO
 import time, logging
-from threading import Event, Lock
+from threading import Event
 from exceptionThreading import ExceptionThread
 from itertools import chain
 
@@ -13,8 +13,14 @@ class Blinkenlights(ExceptionThread):
 	def __init__(self, pin, cyclePeriod=2):
 		self._stopper = Event()
 		self._blink = Event()
-		self._lock = Lock()
+		self._linear = Event()
 		
+		# number of pwm adjustments madeper duty cycle, note stepsize is in half
+		# because we spend first half of period decreasing duty cycle and the
+		# second half increasing (between 0 and 100)
+		self._steps = 40
+		self._stepsize = 100/(self._steps/2)
+	
 		self._pin = pin
 		
 		self.setCyclePeriod(cyclePeriod) #cyclePeriod is length of one blink cycle in seconds
@@ -22,13 +28,35 @@ class Blinkenlights(ExceptionThread):
 		GPIO.setup(pin, GPIO.OUT)
 		pwm = GPIO.PWM(self._pin, 60)
 		
+		def linearLoop():
+			for dc in chain(range(100, -1, -self._stepsize), range(0, 101, self._stepsize)):
+				t = (self._linear.is_set(), self._blink.is_set())
+				if t == (True, True):
+					pwm.ChangeDutyCycle(dc)
+					time.sleep(self._sleeptime)
+				else:
+					return t
+			return (True, True)
+		
 		def blinkLights():
 			pwm.start(0)
 			while not self._stopper.isSet():
 				if self._blink.is_set():
-					for dc in chain(range(100, -1, -5), range(0, 101, 5)):
-						pwm.ChangeDutyCycle(dc)
-						time.sleep(self._sleeptime)
+					linearSet, blinkSet = linearLoop()
+					
+					if not blinkSet:
+						continue
+					elif not linearSet:
+						t = self._sleeptime*self._stepsize
+					
+						pwm.ChangeDutyCycle(100)
+						self._linear.wait(timeout=t)
+						
+						if self._linear.is_set() or not self._blink.is_set():
+							continue
+							
+						pwm.ChangeDutyCycle(0)
+						self._linear.wait(timeout=t)
 				else:
 					pwm.ChangeDutyCycle(100)
 					self._blink.wait()			
@@ -44,15 +72,25 @@ class Blinkenlights(ExceptionThread):
 		if self.is_alive():
 			self._stopper.set()
 			self._blink.set()
+			self._linear.set()
 			logger.debug('Stopping LED on pin %s', self._pin)
 
 	def setCyclePeriod(self, cyclePeriod):
-		with self._lock:
-			self._sleeptime = cyclePeriod/20/2
-		
+		self._sleeptime = cyclePeriod/self._steps
+			
+	def setLinear(self, toggle):
+		if toggle:
+			self._linear.set()
+		else:
+			self._linear.clear()
+
 	def setBlink(self, toggle):
 		if toggle:
 			self._blink.set()
+			# unblock the _linear Event if threads are waiting on it
+			if not self._linear.is_set():
+				self._linear.set()
+				self._linear.clear()
 		else:
 			self._blink.clear()