Transmitter.py

import serial
import time

print("Start")
port="COM4" #This will be different for various devices and on windows it will probably be a COM port.
bluetooth=serial.Serial(port, 9600)#Start communications with the bluetooth unit
print("Connected")
bluetooth.flushInput() #This gives the bluetooth a little kick

for i in range(5): #send 5 groups of data to the bluetooth
    if i == 0:
        bluetooth.write(b"LED ON")  # Turn Off the LED
    else:
        bluetooth.write(b"DATA "+str.encode(str(i)))#These need to be bytes not unicode, plus a number
    input_data=bluetooth.readline()#This reads the incoming data. In this particular example it will be the "Bluetooth answers" line
    print(input_data.decode())#These are bytes coming in so a decode is needed
    time.sleep(0.1) #A pause between bursts

bluetooth.write(b"LED OFF") #Turn Off the LED, but no answer back from Bluetooth will be printed by python

bluetooth.close() #Otherwise the connection will remain open until a timeout which ties up the /dev/thingamabob
print("Done")