Initial travler-rotor library scaffolding

Extract Gabe Emerson's Trav'ler rotor scripts into a proper Python
library with firmware protocol abstraction (HAL 2.05 + HAL 0.0.00),
Hamlib rotctld TCP server, Click CLI, and isolated leap-frog algorithm
with the elevation copy-paste bug fixed.

Trav-ler-Rotor-For-HAL-2.05/travler_rotor.py

@@ -0,0 +1,159 @@
+#Python program to control Winegard Trav'ler antenna as an AZ/EL Rotor
+#Version 2.0B (For HAL Version 2.05, NOT for HAL v0.0)
+#Gabe Emerson / Saveitforparts 2025, Email: gabe@saveitforparts.com
+
+import serial
+import socket 
+import regex as re
+
+#initialize some variables
+current_az = 0.0  
+current_el = 0.0
+move_nbr = 0
+
+#define "antenna" as the serial port device to interface with
+antenna = serial.Serial(
+	port='/dev/ttyUSB0',             #pass this from command line in future?
+	baudrate = 57600,
+	parity=serial.PARITY_NONE,
+	stopbits=serial.STOPBITS_ONE,
+	bytesize=serial.EIGHTBITS,
+	timeout=1)
+
+print ('Antenna connected on ', antenna.port)
+
+#Prep the Trav'ler firmware to accept commands
+antenna.write(bytes(b'q\r')) #go back to root menu in case firmware was left in a submenu
+antenna.write(bytes(b'\r')) #clear firmware prompt to avoid unknown command errors
+antenna.write(bytes(b'motor\r')) #enter motor submenu
+
+#listen to local port for rotctld commands
+listen_ip = '127.0.0.1'  #listen on localhost
+listen_port = 4533     #pass this from command line in future?
+client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+client_socket.bind((listen_ip, listen_port))
+client_socket.listen(1)
+
+while 1:
+	print ('Listening for rotor commands on', listen_ip, ':', listen_port)
+	print ('Ctrl-C to exit')
+	conn, addr = client_socket.accept()
+	print ('Connection from ',addr)
+	
+	#pass rotor commands to antenna
+	while 1:
+		data = conn.recv(100)  #get Gpredict's message
+		if not data:
+			break
+			
+		cmd = data.decode("utf-8").strip().split(" ")   #grab the incoming command
+		
+		if cmd[0] == "p":   #Gpredict is requesting position
+			
+			#ask antenna for position
+			antenna.write(bytes(b'a\r')) #get current Az/El/Sk
+			antenna.flush()	
+			
+			#read current position from antenna
+			reply1 = antenna.read(200).decode(errors='ignore').strip()      #read dish response
+			
+			#Regular expression patterns to find AZ and EL values
+			az_pattern = r"AZ =(\s+\d+\.\d+)"
+			el_pattern = r"EL =(\s+\d+\.\d+)"
+	
+			#Use re.search to extract the values
+			az_match = re.search(az_pattern, reply1)
+			el_match = re.search(el_pattern, reply1)
+	
+			#If matches are found, extract the numerical values
+			if az_match and el_match:
+			    current_az = float(az_match.group(1))
+			    current_el = float(el_match.group(1))
+			else:
+			    print("AZ or EL not found.")
+			
+			print("Current position:", current_az,", ", current_el)
+			
+			response = "{}\n{}\n".format(current_az, current_el) #put az & el into the format Gpredict expects
+			conn.send(response.encode('utf-8')) #send response to Gpredict
+			antenna.flush()
+			
+		elif cmd[0] == "P":   #Gpredict is sending desired position
+		
+			target_az = float(cmd[1])
+			target_el = float(cmd[2])
+			print('Gpredict requesting move to:', target_az,', ', target_el)
+			print('\n')
+			
+			#Set movement a little farther than requested to "leap-frog" over position. 
+			#This helps avoid the antenna lagging behind the satellite in the middle of the pass
+			if target_az - current_az > 2:
+				target_az+=1
+			elif target_az - current_az < -2:
+				target_az-=1	
+			elif target_az - current_az > 1:
+				target_az+=0.5
+			elif target_az - current_az < -1:
+				target_az-=0.5	
+			if target_el - current_el > 2:
+				target_az+=1
+			elif target_el - current_el < -2:
+				target_az-=1	
+			elif target_el - current_el > 1:
+				target_az+=0.5
+			elif target_el - current_el < -1:
+				target_az-=0.5	
+		
+			#tell Antenna to move to target position 
+			#Alternate AZ and EL motions to avoid one waiting on the other
+			if (move_nbr % 2) == 0: #Even numbered step, send AZ first
+				
+				command = ('a 0 ' + str(target_az) + '\r').encode('ascii') #move azimuth motor
+				antenna.write(command)
+			
+				#tell Antenna to move to target el
+				if (target_el < 15):  #HAL 2.05 won't reliably go below 15 degrees with this method
+					target_el = 15
+				command = ('a 1 ' + str(target_el) + '\r').encode('ascii') #move elevation motor
+				antenna.write(command)	
+			
+			else: #Odd numbered step, send EL first
+				
+				#tell Antenna to move to target el
+				if (target_el < 15):  
+					target_el = 15
+				command = ('a 1 ' + str(target_el) + '\r').encode('ascii') #move elevation motor
+				antenna.write(command)	
+				
+				#tell Antenna to move to target az
+				command = ('a 0 ' + str(target_az) + '\r').encode('ascii') #move azimuth motor
+				antenna.write(command)
+						
+			#Tell Gpredict things went correctly
+			response="RPRT 0\n "  #Everything's under control, situation normal
+			conn.send(response.encode('utf-8'))
+			move_nbr+=1 #increment step counter
+			
+			
+		elif cmd[0] == "S": #Gpredict says to stop, so exit loop and listen for a new connection
+			print('Gpredict disconnected!') 
+			move_nbr = 0
+			conn.close()
+			break
+						
+		elif cmd[0] == "_": #Gpredict asks for model name (does it ever do this?)
+			response = "Saveitforparts Winegard Trav'ler Interface v2.0"
+			conn.send(response.encode('utf-8'))
+			
+		else:
+			print('Exiting.')
+			antenna.write(bytes(b'q\r')) #go back to root menu
+			antenna.write(bytes(b'\r'))
+			conn.close()
+			antenna.close()
+			exit()
+	
+	
+	
+	
+