Tutorial

Listing accessible event devices

>>> import evdev

>>> devices = [evdev.InputDevice(fn) for fn in evdev.list_devices()]
>>> for device in devices:
>>>     print(device.fn, device.name, device.phys)
/dev/input/event1    Dell Dell USB Keyboard   usb-0000:00:12.1-2/input0
/dev/input/event0    Dell USB Optical Mouse   usb-0000:00:12.0-2/input0

Listing device capabilities

>>> import evdev

>>> device = evdev.InputDevice('/dev/input/event0')
>>> print(device)
device /dev/input/event0, name "Dell USB Optical Mouse", phys "usb-0000:00:12.0-2/input0"

>>> device.capabilities()
... { 0: [0, 1, 2], 1: [272, 273, 274, 275], 2: [0, 1, 6, 8], 4: [4] }

>>> device.capabilities(verbose=True)
... { ('EV_SYN', 0): [('SYN_REPORT', 0), ('SYN_CONFIG', 1), ('SYN_MT_REPORT', 2)],
...   ('EV_KEY', 1): [('BTN_MOUSE', 272), ('BTN_RIGHT', 273), ('BTN_MIDDLE', 274), ('BTN_SIDE', 275)], ...

Listing device capabilities (devices with absolute axes)

>>> import evdev

>>> device = evdev.InputDevice('/dev/input/event7')
>>> print(device)
device /dev/input/event7, name "Wacom Bamboo 2FG 4x5 Finger", phys ""

>>> device.capabilities()
... { 1: [272, 273, 277, 278, 325, 330, 333] ,
...   3: [(0, AbsInfo(min=0, max=15360, fuzz=128, flat=0)),
...       (1, AbsInfo(min=0, max=10240, fuzz=128, flat=0))] }

>>> device.capabilities(verbose=True)
... { ('EV_KEY', 1): [('BTN_MOUSE', 272), ('BTN_RIGHT', 273), ...],
...   ('EV_ABS', 3): [(('ABS_X', 0), AbsInfo(min=0, max=15360, fuzz=128, flat=0)),
...                   (('ABS_Y', 1), AbsInfo(min=0, max=10240, fuzz=128, flat=0)),] }

>>> device.capabilities(absinfo=False)
... { 1: [272, 273, 277, 278, 325, 330, 333],
...   3: [0, 1, 47, 53, 54, 57] }

Getting and setting LED states

>>> dev.leds(verbose=True)
... [('LED_NUML', 0), ('LED_CAPSL', 1)]

>>> dev.leds()
... [0, 1]

>>> dev.set_led(ecodes.LED_NUML, 1)  # enable numlock
>>> dev.set_led(ecodes.LED_NUML, 0)  # disable numlock

Getting currently active keys

>>> dev.active_keys(verbose=True)
... [('KEY_3', 4), ('KEY_LEFTSHIFT', 42)]

>>> dev.active_keys()
... [4, 42]

Reading events

Reading events from a single device in an endless loop.

>>> from evdev import InputDevice, categorize, ecodes
>>> dev = InputDevice('/dev/input/event1')

>>> print(dev)
device /dev/input/event1, name "Dell Dell USB Keyboard", phys "usb-0000:00:12.1-2/input0"

>>> for event in dev.read_loop():
...     if event.type == ecodes.EV_KEY:
...         print(categorize(event))
... # pressing 'a' and holding 'space'
key event at 1337016188.396030, 30 (KEY_A), down
key event at 1337016188.492033, 30 (KEY_A), up
key event at 1337016189.772129, 57 (KEY_SPACE), down
key event at 1337016190.275396, 57 (KEY_SPACE), hold
key event at 1337016190.284160, 57 (KEY_SPACE), up

Reading events (using asyncore)

>>> from asyncore import file_dispatcher, loop
>>> from evdev import InputDevice, categorize, ecodes
>>> dev = InputDevice('/dev/input/event1')

>>> class InputDeviceDispatcher(file_dispatcher):
...     def __init__(self, device):
...         self.device = device
...         file_dispatcher.__init__(self, device)
...
...     def recv(self, ign=None):
...         return self.device.read()
...
...     def handle_read(self):
...         for event in self.recv():
...             print(repr(event))

>>> InputDeviceDispatcher(dev)
>>> loop()
InputEvent(1337255905L, 358854L, 1, 30, 0L)
InputEvent(1337255905L, 358857L, 0, 0, 0L)

Note

The asyncore module is deprecated in recent versions of Python. Please consider using asyncio.

Reading events from multiple devices (using select)

>>> from evdev import InputDevice
>>> from select import select

# A mapping of file descriptors (integers) to InputDevice instances.
>>> devices = map(InputDevice, ('/dev/input/event1', '/dev/input/event2'))
>>> devices = {dev.fd: dev for dev in devices}

>>> for dev in devices.values(): print(dev)
device /dev/input/event1, name "Dell Dell USB Keyboard", phys "usb-0000:00:12.1-2/input0"
device /dev/input/event2, name "Logitech USB Laser Mouse", phys "usb-0000:00:12.0-2/input0"

>>> while True:
...    r, w, x = select(devices, [], [])
...    for fd in r:
...        for event in devices[fd].read():
...            print(event)
event at 1351116708.002230, code 01, type 02, val 01
event at 1351116708.002234, code 00, type 00, val 00
event at 1351116708.782231, code 04, type 04, val 458782
event at 1351116708.782237, code 02, type 01, val 01

Reading events from multiple devices (using selectors)

This can also be achieved using the selectors module in Python 3.4:

from evdev import InputDevice
from selectors import DefaultSelector, EVENT_READ

selector = selectors.DefaultSelector()

mouse = evdev.InputDevice('/dev/input/event1')
keybd = evdev.InputDevice('/dev/input/event2')

# This works because InputDevice has a `fileno()` method.
selector.register(mouse, selectors.EVENT_READ)
selector.register(keybd, selectors.EVENT_READ)

while True:
    for key, mask in selector.select():
        device = key.fileobj
        for event in device.read():
            print(event)

Reading events from multiple devices (using asyncio)

Yet another possibility is the asyncio module from Python 3.4:

import asyncio, evdev

@asyncio.coroutine
def print_events(device):
    while True:
        events = yield from device.async_read()
        for event in events:
            print(device.fn, evdev.categorize(event), sep=': ')

mouse = evdev.InputDevice('/dev/input/eventX')
keybd = evdev.InputDevice('/dev/input/eventY')

for device in mouse, keybd:
    asyncio.async(print_events(device))

loop = asyncio.get_event_loop()
loop.run_forever()

Since Python 3.5, the async/await syntax makes this even simpler:

import asyncio, evdev

mouse = evdev.InputDevice('/dev/input/event4')
keybd = evdev.InputDevice('/dev/input/event5')

async def print_events(device):
    async for event in device.async_read_loop():
        print(device.fn, evdev.categorize(event), sep=': ')

for device in mouse, keybd:
    asyncio.ensure_future(print_events(device))

loop = asyncio.get_event_loop()
loop.run_forever()

Accessing evdev constants

>>> from evdev import ecodes

>>> ecodes.KEY_A, ecodes.ecodes['KEY_A']
... (30, 30)
>>> ecodes.KEY[30]
... 'KEY_A'
>>> ecodes.bytype[ecodes.EV_KEY][30]
... 'KEY_A'
>>> ecodes.KEY[152]  # a single value may correspond to multiple codes
... ['KEY_COFFEE', 'KEY_SCREENLOCK']

Getting exclusive access to a device

>>> dev.grab()  # become the sole recipient of all incoming input events
>>> dev.ungrab()

Associating classes with event types

>>> from evdev import categorize, event_factory, ecodes

>>> class SynEvent(object):
...     def __init__(self, event):
...         ...

>>> event_factory[ecodes.EV_SYN] = SynEvent

See events for more information.

Injecting input

>>> from evdev import UInput, ecodes as e

>>> ui = UInput()

>>> # accepts only KEY_* events by default
>>> ui.write(e.EV_KEY, e.KEY_A, 1)  # KEY_A down
>>> ui.write(e.EV_KEY, e.KEY_A, 0)  # KEY_A up
>>> ui.syn()

>>> ui.close()

Injecting events (using a context manager)

>>> ev = InputEvent(1334414993, 274296, ecodes.EV_KEY, ecodes.KEY_A, 1)
>>> with UInput() as ui:
...    ui.write_event(ev)
...    ui.syn()

Specifying uinput device options

>>> from evdev import UInput, AbsInfo, ecodes as e

>>> cap = {
...     e.EV_KEY : [e.KEY_A, e.KEY_B],
...     e.EV_ABS : [
...         (e.ABS_X, AbsInfo(value=0, min=0, max=255,
...                           fuzz=0, flat=0, resolution=0)),
...         (e.ABS_Y, AbsInfo(0, 0, 255, 0, 0, 0)),
...         (e.ABS_MT_POSITION_X, (0, 255, 128, 0)) ]
... }

>>> ui = UInput(cap, name='example-device', version=0x3)
>>> print(ui)
name "example-device", bus "BUS_USB", vendor "0001", product "0001", version "0003"
event types: EV_KEY EV_ABS EV_SYN

>>> print(ui.capabilities())
{0: [0, 1, 3],
 1: [30, 48],
 3: [(0,  AbsInfo(value=0, min=0, max=0,   fuzz=255, flat=0, resolution=0)),
     (1,  AbsInfo(value=0, min=0, max=0,   fuzz=255, flat=0, resolution=0)),
     (53, AbsInfo(value=0, min=0, max=255, fuzz=128, flat=0, resolution=0))]}

>>> # move mouse cursor
>>> ui.write(e.EV_ABS, e.ABS_X, 20)
>>> ui.write(e.EV_ABS, e.ABS_Y, 20)
>>> ui.syn()

Create uinput device with capabilities of another device

>>> from evdev import UInput, InputDevice

>>> mouse = InputDevice('/dev/input/event1')from evdev import UInput, InputDevice
>>> keybd = '/dev/input/event2'

>>> ui = UInput.from_device(mouse, keybd, name='keyboard-mouse-device')
>>> ui.capabilities(verbose=True).keys()
dict_keys([('EV_LED', 17), ('EV_KEY', 1), ('EV_SYN', 0), ('EV_REL', 2), ('EV_MSC', 4)])