USB - HID human interface device

With this python script you can capture keyboard (emulators) and barcode scanners trough evdev (event device), this way the part of code will only execute when the device is sending keys:

from evdev import *
dev = InputDevice('/dev/input/event1')

print(dev)

for event in dev.read_loop():
    if event.type == ecodes.EV_KEY:
        print(categorize(event))

from evdev import *

dev = InputDevice('/dev/input/event1')

print(dev)

for event in dev.read_loop():

if event.type == ecodes.EV_KEY:

print(categorize(event))

output:

key event at 1383327570.147000, 2 (KEY_1), down
key event at 1383327570.147990, 2 (KEY_1), up
key event at 1383327570.148997, 3 (KEY_2), down
key event at 1383327570.150010, 3 (KEY_2), up
key event at 1383327570.151009, 29 (KEY_LEFTCTRL), down
key event at 1383327570.151009, 42 (KEY_LEFTSHIFT), down
key event at 1383327570.152017, 36 (KEY_J), down
key event at 1383327570.153005, 36 (KEY_J), up
key event at 1383327570.154004, 29 (KEY_LEFTCTRL), up
key event at 1383327570.155005, 32 (KEY_D), down
key event at 1383327570.155993, 32 (KEY_D), up
key event at 1383327570.157002, 48 (KEY_B), down
key event at 1383327570.158015, 48 (KEY_B), up
key event at 1383327570.158997, 48 (KEY_B), down
key event at 1383327570.282002, 18 (KEY_E), up
key event at 1383327570.283004, 49 (KEY_N), down
key event at 1383327570.284005, 49 (KEY_N), up
key event at 1383327570.284968, 18 (KEY_E), down

key event at 1383327570.147000, 2 (KEY_1), down

key event at 1383327570.147990, 2 (KEY_1), up

key event at 1383327570.148997, 3 (KEY_2), down

key event at 1383327570.150010, 3 (KEY_2), up

key event at 1383327570.151009, 29 (KEY_LEFTCTRL), down

key event at 1383327570.151009, 42 (KEY_LEFTSHIFT), down

key event at 1383327570.152017, 36 (KEY_J), down

key event at 1383327570.153005, 36 (KEY_J), up

key event at 1383327570.154004, 29 (KEY_LEFTCTRL), up

key event at 1383327570.155005, 32 (KEY_D), down

key event at 1383327570.155993, 32 (KEY_D), up

key event at 1383327570.157002, 48 (KEY_B), down

key event at 1383327570.158015, 48 (KEY_B), up

key event at 1383327570.158997, 48 (KEY_B), down

key event at 1383327570.282002, 18 (KEY_E), up

key event at 1383327570.283004, 49 (KEY_N), down

key event at 1383327570.284005, 49 (KEY_N), up

key event at 1383327570.284968, 18 (KEY_E), down

Another python script example:

import evdev
from evdev import InputDevice, categorize  # import * is evil :)
dev = InputDevice('/dev/input/event1')

# Provided as an example taken from my own keyboard attached to a Centos 6 box:
scancodes = {
    # Scancode: ASCIICode
    0: None, 1: u'ESC', 2: u'1', 3: u'2', 4: u'3', 5: u'4', 6: u'5', 7: u'6', 8: u'7', 9: u'8',
    10: u'9', 11: u'0', 12: u'-', 13: u'=', 14: u'BKSP', 15: u'TAB', 16: u'Q', 17: u'W', 18: u'E', 19: u'R',
    20: u'T', 21: u'Y', 22: u'U', 23: u'I', 24: u'O', 25: u'P', 26: u'[', 27: u']', 28: u'CRLF', 29: u'LCTRL',
    30: u'A', 31: u'S', 32: u'D', 33: u'F', 34: u'G', 35: u'H', 36: u'J', 37: u'K', 38: u'L', 39: u';',
    40: u'"', 41: u'`', 42: u'LSHFT', 43: u'\\', 44: u'Z', 45: u'X', 46: u'C', 47: u'V', 48: u'B', 49: u'N',
    50: u'M', 51: u',', 52: u'.', 53: u'/', 54: u'RSHFT', 56: u'LALT', 100: u'RALT'
}
for event in dev.read_loop():
    if event.type == evdev.ecodes.EV_KEY:
        data = evdev.categorize(event)  # Save the event temporarily to introspect it
        if data.keystate == 1:  # Down events only
            key_lookup = scancodes.get(data.scancode) or u'UNKNOWN:{}'.format(data.scancode)  # Lookup or return UNKNOWN:XX
            print u'You Pressed the {} key!'.format(key_lookup)  # Print it all out!

import evdev

from evdev import InputDevice, categorize # import * is evil :)

dev = InputDevice('/dev/input/event1')

# Provided as an example taken from my own keyboard attached to a Centos 6 box:

scancodes = {

# Scancode: ASCIICode

0: None, 1: u'ESC', 2: u'1', 3: u'2', 4: u'3', 5: u'4', 6: u'5', 7: u'6', 8: u'7', 9: u'8',

10: u'9', 11: u'0', 12: u'-', 13: u'=', 14: u'BKSP', 15: u'TAB', 16: u'Q', 17: u'W', 18: u'E', 19: u'R',

20: u'T', 21: u'Y', 22: u'U', 23: u'I', 24: u'O', 25: u'P', 26: u'[', 27: u']', 28: u'CRLF', 29: u'LCTRL',

30: u'A', 31: u'S', 32: u'D', 33: u'F', 34: u'G', 35: u'H', 36: u'J', 37: u'K', 38: u'L', 39: u';',

40: u'"', 41: u'`', 42: u'LSHFT', 43: u'\\', 44: u'Z', 45: u'X', 46: u'C', 47: u'V', 48: u'B', 49: u'N',

50: u'M', 51: u',', 52: u'.', 53: u'/', 54: u'RSHFT', 56: u'LALT', 100: u'RALT'

}

for event in dev.read_loop():

if event.type == evdev.ecodes.EV_KEY:

data = evdev.categorize(event) # Save the event temporarily to introspect it

if data.keystate == 1: # Down events only

key_lookup = scancodes.get(data.scancode) or u'UNKNOWN:{}'.format(data.scancode) # Lookup or return UNKNOWN:XX

print u'You Pressed the {} key!'.format(key_lookup) # Print it all out!

Output:

You Pressed the A key!
You Pressed the B key!
You Pressed the C key!
You Pressed the UNKNOWN:99 key!

You Pressed the A key!

You Pressed the B key!

You Pressed the C key!

You Pressed the UNKNOWN:99 key!

Source: https://stackoverflow.com/questions/19732978/how-can-i-get-a-string-from-hid-device-in-python-with-evdev

Zoeken

USB – HID human interface device