This is a program I wrote while working as a projectionist at a movie theater after their automation which controls the projector power failed.

gistfile1.py

#!/usr/bin/env python
from Tkinter import *
from socket import *
port = 7142
on = '02 00 00 00 00'
off = '02 01 00 00 00'

lamp = "03 2F 00 00 02 12"
shutter = "02 17 00 00 00"

def callback_power_on(data, host):
    try:
        connection = socket(AF_INET, SOCK_STREAM)
        connection.connect((host, port))
        connection.sendall(add_checksum(data))
        connection.close()
        test_var = add_checksum(data)
        print test_var
        return 1
    except: pass


def callback_shutter(data, host):
    try:
        connection = socket(AF_INET, SOCK_STREAM)
        connection.connect((host, port))
        connection.sendall(add_checksum(data))
        onnection.close()
       # test_var = add_checksum(data)
        print test_var
        return 1
    except: pass
def callback_power_off(data):
    try:
        connection = socket(AF_INET, SOCK_STREAM)
        connection = socket(AF_INET, SOCK_STREAM)
        connection.connect((host, port))
        connection.sendall(add_checksum(data))
        connection.close()
        test_var = add_checksum(data)
        print test_var
        return 1
    except: pass
    connection = socket(AF_INET, SOCK_STREAM)
    connection = socket(AF_INET, SOCK_STREAM)
    connection.connect((host, port))
    connection.sendall(add_checksum(data))
    connection.close()
        
def add_checksum(s):
    result = []
    acc = 0
    for hexcode in s.split():
        code = int(hexcode, 16)
        acc += code
        result.append(chr(code))
    result.append(chr(acc))
    return ''.join(result)

def format_wih_checksum(s):
    """Given a string of whitespace-separated, two-digit hexadecimal
        representations of byte values, returns a string of the represented byte
        values, followed by a checksum byte.  The checksum is the sum of the input
        string's byte values, modulo 256.
        """
    xs = [int(x, 16) for x in s.split()]
    return ''.join(chr(x) for x in xs) + chr(sum(xs))
    print ''.join(chr(x) for x in xs) + chr(sum(xs))

master = Tk()
host = StringVar()

Radiobutton(master, text="Silas",indicatoron = 0, variable = host, value ='172.25.13.10').pack(anchor=W)
Radiobutton(master, text="Beatrice", indicatoron = 0, variable = host, value ='172.25.13.12').pack(anchor=W)

b = Button(
    master,
    text="Power On",
    command=lambda: callback_power_on(on, host.get()))
b.pack()

c = Button(
    master,
    text="Power Off",
    command=lambda: callback_power_off(off, host.get()))
c.pack()
d = Button(
    master,
    text="Dowser Open",
    command=lambda: callback_shutter(shutter, host.get()))
d.pack()
mainloop()