read.py

import usb.core
import usb.util
import sys

VENDOR_ID = 0x0922
PRODUCT_ID = 0x8003

DATA_MODE_GRAMS = 2
DATA_MODE_OUNCES = 11

# find the USB device
device = usb.core.find(idVendor=VENDOR_ID,
                       idProduct=PRODUCT_ID)

if device.is_kernel_driver_active(0):
    device.detach_kernel_driver(0)
usb.util.claim_interface(device, 0)

# use the first/default configuration

# first endpoint
endpoint = device[0][(0,0)][0]

# read a data packet
while True:
     attempts = 10
     data = None
     while data is None and attempts > 0:
         try:
             data = device.read(endpoint.bEndpointAddress,
                                endpoint.wMaxPacketSize)
         except usb.core.USBError as e:
             data = None
             if e.args == ('Operation timed out',):
                 attempts -= 1
                 continue

     raw_weight = data[4] + data[5] * 256
     if data[2] == DATA_MODE_OUNCES:
         ounces = raw_weight * 1
         weight = "%s oz" % ounces
     elif data[2] == DATA_MODE_GRAMS:
         grams = raw_weight
         weight = "%s g" % grams

     print weight