mqtt_pi_led-display/src/controller.py

import paho.mqtt.client as mqtt

import time
import board
import busio
from adafruit_ht16k33 import segments
from enum import Enum

__TOPIC_BRIGHTNESS__ = "brightness"
__TOPIC_SCROLL_INTERVAL__ = "scrollinterval"
__TOPIC_TEXT_STATIC__ = "textstatic"
__TOPIC_TEXT_ONCE__ = "textonce"
__TOPIC_TEXT_SCROLL__ = "textscroll"
__TOPIC_TEXT_MARQUEE__ = "textmarquee"
__TOPIC_TEXT_PAN__ = "textpan"

NUMDIGITS = 8

class Mode(Enum):
	STATIC = 1 #show text constantly. may cut digits
	ONCE = 3 #show once for some time
	SCROLL = 2 #scroll thorugh once
	PAN = 4 #scroll back and forth
	MARQUEE = 5

class Controller:
	connected = False
	displayL = None
	displayR = None
	
	

	def __init__(self, base_topic, mqtt_host, mqtt_port = 1883):

		self.scroll_interval = 0.25
		self.text = "        "
		self.text_last = ""
		self.poscount = 0
		self.last_scrollupdate = 0
		self.mode = Mode.STATIC
		
		
		# Create the I2C interface.
		self.i2c = busio.I2C(board.SCL, board.SDA)
		
		# Create the LED segment class.
		# This creates a 14 segment 4 character display:
		self.displayL = segments.Seg14x4(self.i2c, address=0x70) # find address with "sudo i2cdetect -y 1"   . you need to install: sudo apt-get install -y python-smbus i2c-tools
		self.displayR = segments.Seg14x4(self.i2c, address=0x71)
		
		# Clear the display.
		self.displayL.fill(0)
		self.displayR.fill(0)
		
		# set brightness, range 0-1.0, 1.0 max brightness
		self.displayL.brightness = 1.0
		self.displayR.brightness = 1.0
		
		self.mqtt = mqtt.Client()
		self.mqtt.on_connect = self.on_connect
		self.mqtt.on_message = self.on_message
		self.mqtt.on_disconnect = self.on_disconnect
		self.mqtt.connect(mqtt_host, mqtt_port)
		self.topic = base_topic
		
		self.displayL.print("LEFT")
		self.displayR.print("RIGH")


	def on_disconnect(self, client, userdata, rc):
		print("MQTT disconnected")
		self.connected = False

	def on_message(self, client, userdata, message):
		msg = str(message.payload.decode("utf-8"))
		print("msg = " +  msg)
		
		if message.topic.endswith(__TOPIC_BRIGHTNESS__ + "/set"):
			val = float(msg)
			if val >= 0.0 and val <=1.0:
				self.displayL.brightness = val
				self.displayR.brightness = val
				print("changed brightness to ", self.displayL.brightness)
				self.mqtt.publish(self.topic + "/" + __TOPIC_BRIGHTNESS__, self.displayL.brightness, 1 )
			else:
				print("invalid brightness ", val)
		
		if message.topic.endswith(__TOPIC_SCROLL_INTERVAL__ + "/set"):
			val = float(msg)
			if val > 0.0:
				self.scroll_interval = val
				print("changed scroll_interval to ", self.scroll_interval)
				self.mqtt.publish(self.topic + "/" + __TOPIC_SCROLL_INTERVAL__, self.scroll_interval, 1 )
			else:
				print("error not >0.0: ", val)
		
		if message.topic.endswith(__TOPIC_TEXT_STATIC__ + "/set"):
			self.mode = Mode.STATIC
			self.text = msg.ljust(NUMDIGITS)
			print("changed text to ", self.text)
			self.mqtt.publish(self.topic + "/" + __TOPIC_TEXT_STATIC__, self.text, 1 )
		
		if message.topic.endswith(__TOPIC_TEXT_MARQUEE__ + "/set"):
			self.mode = Mode.MARQUEE
			self.poscount = 0 #start at beginning of new text
			self.text = msg
			for i in range(NUMDIGITS):
				self.text = " "+self.text+" " #add spaces left and right for marquee to enter and leave the full frame
			print("changed text to ", self.text)
			self.mqtt.publish(self.topic + "/" + __TOPIC_TEXT_MARQUEE__, self.text, 1 )
			
		if message.topic.endswith(__TOPIC_TEXT_PAN__ + "/set"):
			self.mode = Mode.PAN
			self.poscount = 0 #start at beginning of new text
			self.text = msg
			for i in range(int(NUMDIGITS/4)):
				self.text = " "+self.text+" " #add spaces left and right for marquee to enter and leave the full frame
			print("changed text to ", self.text)
			self.mqtt.publish(self.topic + "/" + __TOPIC_TEXT_PAN__, self.text, 1 )
			
		if message.topic.endswith(__TOPIC_TEXT_SCROLL__ + "/set"):
			self.mode = Mode.SCROLL
			self.poscount = 0 #start at beginning of new text
			self.text = msg
			for i in range(NUMDIGITS):
				self.text = " "+self.text+" " #add spaces left and right for marquee to enter and leave the full frame
			print("changed text to ", self.text)
			self.mqtt.publish(self.topic + "/" + __TOPIC_TEXT_SCROLL__, self.text, 1 )


	def on_connect(self, client, userdata, flags, rc):
		print("Connected to MQTT Broker")
		self.mqtt.subscribe(self.topic + "/#")
		self.connected = True
		
	def writeSegment(self, _digit, _char, clear=False):
		if _digit>=0 and _digit<4:
			if clear:
				self.displayL[_digit]=' '
			self.displayL[_digit] = _char
		elif _digit<8:
			if clear:
				self.displayR[_digit-4]=' '
			self.displayR[_digit-4] = _char

	def displayTextOffset(self, _text, _offset = 0):
		# This function is needed because library print functions only work for a single display module. This function handles the '.' character with its special cases.
		
		_text+="        " #append NUMDIGITS spaces at end for when scrolling past end
			
		
			
		_text=_text[_offset:] #move by offset
		
		i=0 #counter for reading pos
		d=0 #counter for writing segment pos
		while d<NUMDIGITS and i<len(_text):
		
			if _text[i]=='.' and _text[max(0,i-1)]=='.': #is dot and was before (or is at start)
				self.writeSegment(d,_text[i],True)				
				d+=1
				i+=1
				
			else:
				if _text[i]!='.' : #normal char
					self.writeSegment(d,_text[i])
					i+=1
					
				if i<len(_text):
					if _text[i]=='.': #dot, but can be appended to last char
						self.writeSegment(d,_text[i])
						i+=1
					
				d+=1
				
	
	def seglen(self, _text): #len function but optimized for 14-segment display
		i=0 #counter for reading pos
		d=0 #counter for writing segment pos
		while i<len(_text):
		
			if _text[i]=='.' and _text[max(0,i-1)]=='.': #is dot and was before (or is at start)		
				d+=1
				i+=1
				
			else:
				if _text[i]!='.' : #normal char
					i+=1
					
				if i<len(_text):
					if _text[i]=='.': #dot, but can be appended to last char
						i+=1
					
				d+=1
				
		return d
		

	def loop_forever(self):
		run = True

		while run:
			self.mqtt.loop(0.1) #with block timeout

			if self.displayL is not None and self.displayR is not None: #displays initialized
			
				if self.mode == Mode.STATIC:
					if self.text != self.text_last: #time to update animation
						self.displayTextOffset(self.text, 0)
			
				if self.mode == Mode.MARQUEE or self.mode == Mode.SCROLL:
					if time.time() > self.last_scrollupdate+self.scroll_interval or self.text != self.text_last: #time to update animation
						self.displayTextOffset(self.text, self.poscount)
						
						self.poscount += 1
						if self.mode == Mode.MARQUEE:
							self.poscount %= max(1,int(self.seglen(self.text)-NUMDIGITS+1))
						elif self.mode == Mode.SCROLL:
							if self.poscount >= max(1,int(self.seglen(self.text)-NUMDIGITS+1)): #reached end for scroll once
								self.mode == Mode.STATIC
								self.text=" ".ljust(NUMDIGITS) #empty
								
						self.last_scrollupdate = time.time()
						
						
				if self.mode == Mode.PAN:
					if time.time() > self.last_scrollupdate+self.scroll_interval or self.text != self.text_last: #time to update animation
						print("pos=", self.poscount)
						scrolloffset = self.poscount
						if scrolloffset >= (self.seglen(self.text)-NUMDIGITS):
							scrolloffset = (self.seglen(self.text)-NUMDIGITS) - (scrolloffset-(self.seglen(self.text)-NUMDIGITS)) #reverse
						scrolloffset = max(0,scrolloffset) #cap at zero
						print("scrolloffset=", scrolloffset)
							
						self.displayTextOffset(self.text, scrolloffset)
						
						self.poscount += 1
						self.poscount %= (self.seglen(self.text)-NUMDIGITS)*2 #if poscount over scrollable width means scroll backwards 
						self.last_scrollupdate = time.time()

				self.text_last = self.text