Serial TX from python to arduino (sending raw bytes) - Plays well with this gist: https://gist.github.com/Robotto/55494b012af0c0f9c9d7c048066c9290

SerialtxFromPythonToArduino.py

import serial #Pakken hedder pyserial
import sys
import glob
import time

def list_ports():
	""" Finds all serial ports and returns a list containing them

		:raises EnvironmentError:
			On unsupported or unknown platforms
		:returns:
			A list of the serial ports available on the system
	"""
	if sys.platform.startswith('win'):
		ports = ['COM%s' % (i + 1) for i in range(254)]
	elif sys.platform.startswith('linux') or sys.platform.startswith('cygwin'):
		# this excludes your current terminal "/dev/tty"
		ports = glob.glob('/dev/tty[A-Za-z]*')
	elif sys.platform.startswith('darwin'):
		ports = glob.glob('/dev/tty.*')
	else:
		raise EnvironmentError('Unsupported platform')

	result = []
	for port in ports:
		try:
			s = serial.Serial(port)	# Try to open a port
			s.close()				  # Close the port if sucessful
			del s					#delete the port object
			result.append(port)		# Add to list of good ports
		except (OSError, Exception):   # If un sucessful
			pass
	return result

baudRate=115200

#foundPorts = list_ports()

#for port in foundPorts:
#	print(f'Found port: {port} (#{foundPorts.index(port)})')
#choice = int(input('Which #? to open:'))

#s = serial.Serial(foundPorts[choice], baudRate, timeout=1)
s = serial.Serial("COM30", baudRate, timeout=1)

txTime=time.time()
position = 0
delta = 1

while(s.is_open):

	if time.time() - txTime > 0.025:
		#position = (position + 1)%180
		position = position + delta
		if position >= 180:
			delta = -1
		if position == 0:
			delta = 1

		s.write(bytes([position]))
		#print(position)
		txTime=time.time()


	if(s.in_waiting>0):
		rxLine=s.readline().decode("ascii").strip()
		print(rxLine)

Arduino code here: https://gist.github.com/Robotto/55494b012af0c0f9c9d7c048066c9290