Polycephaly

Easily create system daemons (and programs) that use an email-like syntax for communicating between threaded and forked processes.

2019-11-08 : Demonstration of Inter-Process Communication, regardless of sub-process’ operating mode.
2019-12-17 : Socketfile example applications
2019-12-17 : Developing with Polycephaly’s communication buses

Hardware

Polycephaly reduces the barrier to entry for creating parallelized system services (specifically, for embedded systems and servers) which can be easily maintained by systemd and other init systems.

Examples of this module working simultaneously with threading and locking applied to precision hardware that’s defined by easy-to-understand JSON profiles that I’ve generated, which correlate to hardware vendors’ communications specifications:

def birth( self, *args, **kwargs ):
 
	self.registerCallbacks(
		connected		=	self.connected,
		disconnected		=	self.disconnected,
		boardPong		=	self.boardPong,
		commsError		=	self.commsError,
		deviceError		=	self.deviceError,
	)
 
	# Prepare keyword arguments that are passed from the main program.
	self.setupGlobalKwargs()
 
	# Add controller's JSON profile to each mapped device.
	self.setupDeviceProfiles()
 
	# Setup and run related device threads (e.g. communications and lighting.)
	self.launchThreads()
 
	# Wait until device path is found by analzying the USB bus before proceeding.
	self.waitForBoardPath()
 
	# Turn on board's green LED
	self.device( self.getDeviceID( 'microcontroller' ) ).led( True )
 
	# Set Servo ID 7 to spin counter-clockwise as fast as possible, and abruptly change direction and speed.
	with self.device( 7 ) as device:
		device.spin( -1023 )
		time.sleep( 5 )
		device.spin( 100 )
 
	pass # END METHOD : Birth

def _threadLeds( self, **kwargs ):
	'''
	Used for controlling LEDs of all connected devices for animations.
	This simple thread iterates colors on all devices at the same time, and then reverses the color direction to reach the starting point, for a seamless transition.
	'''
 
	# Thread loop
	while self.isActive():
 
		for i in range( 1, 8 ):
			self.multiDevice( range( 1, 8 ) ).led( i )
			time.sleep( 0.1 )
			pass # END FOR
 
		for i in reversed( range( 0, 7 ) ):
			self.multiDevice( range( 1, 8 ) ).led( i )
			time.sleep( 0.1 )
 
		time.sleep( 1 )
 
		pass # END WHILE LOOP
 
	pass # END Method : Thread LEDs

Videos

Multiple threads simultaneously controlling hardware: communications (connect/reconnect/disconnect), reading and updating device states, dedicated light patterns being toggled by other threads.

If you look at motors 2 and 3, you’ll notice that the lights come on at the same time. This is because this framework allows for grouping servos together (2 and 3 are), and even inverting values to allow for higher torque.
Multiple threads are working behind the scenes to translate game controller input to a robotic arm prototype that colleagues and I designed from scratch.
Reading hardware state and diagnostics of devices, tracking them in memory, initialization and deploying threads (in this example, persistent communications capable of reconnecting severed connections, light patterns, and an onboard status light) with proper locking against TTL-based communications via USB.
Resetting all devices and disabling all status lights to indicate a proper shutdown.
Simplified methods for alternating a servo’s modes between position as a servo, and direction with speed as a wheel.
Simplified methods for controlling direction and speed as a wheel.