system_monitor.py

from psutil import cpu_percent, net_io_counters
from gpiozero import LEDBarGraph
from time import sleep

graph = LEDBarGraph(12, 21, 20, pwm=True)

#Show CPU occupation percentage

while True:
   graph.value = cpu_percent()/100
   sleep(.1)

    
#Show network activitiy
'''
oldBytes = net_io_counters().bytes_sent + net_io_counters().bytes_recv
while True:
    newBytes = net_io_counters().bytes_sent + net_io_counters().bytes_recv
    diff = newBytes - oldBytes
    oldBytes = newBytes
    print (newBytes)
    
    graph.value = min(1, max(0, diff / 10000)) #constrain value to 0:1
    sleep(.1)
'''