我在Python中使用PyUSB,因为我将不得不听USB端口从电子卡中检索数据。目前,我必须通过从连接到Raspberry-Pi的小键盘(USB连接)读取直接输入来训练自己。当然,我不想读取类型化的String,我希望得到ASCII代码。我只是不知道如何从USB键盘读取输入。
我已经找到了一些片段:
import usb.core
import usb.util
VENDOR_ID = 0x0922
PRODUCT_ID = 0x8003
# find the USB device
device = usb.core.find(idVendor=VENDOR_ID,
idProduct=PRODUCT_ID)
# use the first/default configuration
device.set_configuration()
# first endpoint
endpoint = device[0][(0,0)][0]
# read a data packet
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
print data
我得到错误16“设备正忙”或者什么都没有,如果我取消注释以下行“device.set_configuration()”导致“设备忙”例外...(我确实替换了VENDOR_ID和PRODUCT_ID用我的键盘ids)
答案 0 :(得分:4)
我假设您正在使用Linux,正如您提到的Raspberry Pi。您可以使用python-evdev从/dev/input/
中的事件设备中读取数据。
例如:
from evdev import InputDevice, categorize, ecodes
device = InputDevice("/dev/input/event3") # my keyboard
for event in device.read_loop():
if event.type == ecodes.EV_KEY:
print(categorize(event))
输出:
key event at 1462881252.506405, 30 (KEY_A), up
key event at 1462881252.541371, 31 (KEY_S), up
key event at 1462881252.616399, 31 (KEY_S), down
key event at 1462881252.674422, 22 (KEY_U), down
key event at 1462881252.730418, 31 (KEY_S), up
key event at 1462881252.745558, 22 (KEY_U), up
key event at 1462881252.808419, 50 (KEY_M), down
key event at 1462881252.914552, 23 (KEY_I), down
key event at 1462881252.925388, 50 (KEY_M), up
key event at 1462881253.003579, 49 (KEY_N), down
key event at 1462881253.066418, 34 (KEY_G), down