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Python libusb interface for getting key up/down events from USB HIDs like keyboards.
import sys
import time
import usb
class Button:
def __init__(self, vendor_id, device_id):
"""
Find and open a USB HID device.
"""
self.vendor_id = vendor_id
self.device_id = device_id
self.endpoint = 0x81
self.device = self.getDevice(vendor_id, device_id)
if self.device == None:
raise DeviceNotFound, "No recognised device connected."
self.handle = self.openDevice(self.device)
def __del__(self):
"""
Releases the device.
"""
try:
self.handle.releaseInterface()
del self.handle
except:
pass
def getDevice(self, vendor_id, device_id):
"""
Searches the USB buses for a device matching the given vendor and device IDs.
Returns a usb.Device, or None if the device cannot be found.
"""
busses = usb.busses()
for bus in busses:
devices = bus.devices
for device in devices:
if device.idVendor == vendor_id and device.idProduct == device_id:
return device
return None
def openDevice(self, device):
"""
Opens and claims the specified device. Returns a usb.DeviceHandle
Also attempts to detach the kernel's driver from the device, if necessary.
"""
handle = device.open()
# Attempt to remove other drivers using this device. This is necessary
# for HID devices.
try:
handle.detachKernelDriver(0)
except:
pass # Ignore failures here, the device might already be detached.
handle.claimInterface(0)
return handle
def on_keydown(self):
print "keydown event"
def on_keyup(self):
print "keyup event"
def start(self):
data = None
while True:
try:
data = self.handle.interruptRead(self.endpoint, 8, 0)
except:
raise
if data == (0, 0, 88, 0, 0, 0, 0, 0): # numeric keypad enter pressed
self.on_keydown()
elif data == (0, 0, 0, 0, 0, 0, 0, 0):
self.on_keyup()
data = None
class DeviceNotFound(Exception):
def __init__(self,value):
self.value = value
def __str__(self):
return repr(self.value)
if __name__ == "__main__":
button = Button(0x1710, 0x5612)
button.start()
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