analgauge.py

import usb.core
from psutil import cpu_percent
from time import sleep
from random import random
from sys import exit

#VALUE_MIN = 0x00 # TODO
VALUE_MAX = 0x7B

VENDOR_ID = 0x16c0
PRODUCT_ID = 0x05df

class AnalGauge:
    def __init__(self):
        self.dev = usb.core.find(
            idVendor = VENDOR_ID,
            idProduct = PRODUCT_ID
        )
        if not self.dev:
            print "AnalGauge Device not found!"
            exit(1)

    def update(self, d):
        try:
            data = [int(d)]
            result = self.dev.ctrl_transfer(
                0x21, 0x9,
                wValue = 0x200, wIndex = 0x00,
                data_or_wLength = data
                )
        except usb.core.USBError, e:
            self.dev.detach_kernel_driver(0)
            print(e)

if __name__ == "__main__":
    g = AnalGauge()

    #g.update(VALUE_MAX)
    #exit()

    #while True:
    #    g.update(random() * VALUE_MAX)
    #    sleep(0.5)

    while True:
        pct = cpu_percent(interval=1)
        g.update((VALUE_MAX * pct)/100)