code:

import win32pdh
import serial 
from time import sleep

PdhQuery = win32pdh.OpenQuery(None, 0)
ProcPath = win32pdh.MakeCounterPath((None, "Processor", "_Total", None, 0, "% Processor Time"))
ProcCounter = win32pdh.AddCounter(PdhQuery, ProcPath, 0)
win32pdh.CollectQueryData(PdhQuery)

ser = serial.Serial(2)

def setpriority(pid=None,priority=1):
    """ Set The Priority of a Windows Process.  Priority is a value between 0-5 where
        2 is normal priority.  Default sets the priority of the current
        python process but can take any valid process ID. """
        
    import win32api,win32process,win32con
    
    priorityclasses = [win32process.IDLE_PRIORITY_CLASS,
                       win32process.BELOW_NORMAL_PRIORITY_CLASS,
                       win32process.NORMAL_PRIORITY_CLASS,
                       win32process.ABOVE_NORMAL_PRIORITY_CLASS,
                       win32process.HIGH_PRIORITY_CLASS,
                       win32process.REALTIME_PRIORITY_CLASS]
    if pid == None:
        pid = win32api.GetCurrentProcessId()
    handle = win32api.OpenProcess(win32con.PROCESS_ALL_ACCESS, True, pid)
    win32process.SetPriorityClass(handle, priorityclasses[priority])

setpriority(None,3)

while 1:
	win32pdh.CollectQueryData(PdhQuery)
	format = win32pdh.PDH_FMT_LONG | win32pdh.PDH_FMT_NOSCALE
	idleTime = win32pdh.GetFormattedCounterValue(ProcCounter,format)[1]
	load = idleTime
	#print str(idleTime)
	if load == 100:
		load = 99
	elif load < 10:
		ser.write('0'+str(load))
	else:
    		ser.write(str(load))
    	sleep(.4)