import serial
import time
import sys
from tkinter import *
root = Tk()


ser=serial.Serial('COM7', 9600)

isSerialOpen = True

if isSerialOpen:
    print ("serial connected")
    def key(data):
        frame.focus_force()
        #print ("pressed"),
        repr(data.keysym)
        if data.keysym=="Left":
           ser.write(b'l')
           print("pressed Left")
        if data.keysym=="Right":
            ser.write(b'r')
            print ("pressed Right")
        if data.keysym=="Up":
            ser.write(b'u')
            print ("pressed Up")
        if data.keysym=="Down":
            ser.write(b'd')
            print ("pressed Down")
        if data.keysym=="t":
            ser.write(b't')
            print ("pressed t")
        if data.keysym=="s":
            ser.write(b's')
            print ("pressed s")

frame = Frame(root, width=100, height=100)
frame.bind("<Key>", key)
frame.pack()
frame.focus_set()

root.mainloop()