Liunx下使用Python读取键盘鼠标

在Linux下，可以使用Python直接读取dev/input目录下键盘和鼠标等设备文件，获取数据。

使用Python读取设备数据

例如读取键盘/dev/input/event3:

import struct

with open("/dev/input/event3", "rb") as f:
    while True:
        data = f.read(24)
        time_sec, time_usec, type_, code, value = struct.unpack("QQHHi", data)
        if type_ == 0:
            continue
        print("{}.{}\ttype={}\tcode={}\tvalue={}".format(time_sec, time_usec, type_, code, value))

使用root权限运行程序：

$ sudo python3 demo.py
1591000780.523814       type=4  code=4  value=589825
1591000780.523814       type=1  code=272        value=1
1591000780.691889       type=4  code=4  value=589825
1591000780.691889       type=1  code=272        value=0
1591000781.787812       type=2  code=0  value=1
1591000781.787812       type=2  code=1  value=-1
1591000781.803706       type=2  code=0  value=2
1591000781.843783       type=2  code=0  value=2
1591000781.883777       type=2  code=0  value=2

每一包数据由24个字节组成，其中timeval16字节，type2字节，code2字节，value四字节。C语言结构体如下：

// struct_timeval.h
struct timeval
{
  __time_t tv_sec;      /* Seconds.  */
  __suseconds_t tv_usec;    /* Microseconds.  */
};

// input.h
struct input_event {
    struct timeval time;
    __u16 type;
    __u16 code;
    __s32 value;
};

结构体中type具体内容介绍见https://www.kernel.org/doc/html/v4.17/input/event-codes.html，code内容见头文件input-event-codes.h。

使用evtest查看输入设备数据

另外，如果只是想查看各输入设备的数据，可以使用evtest:
sudo apt install evtest
使用时直接以root权限运行evtest，输入对应编号即可，例如获取编码器数据：

# evtest
No device specified, trying to scan all of /dev/input/event*
Available devices:
/dev/input/event0:      InputEmulator
/dev/input/event1:      rotary-keys
/dev/input/event2:      gpio-keys
Select the device event number [0-2]: 1
Input driver version is 1.0.1
Input device ID: bus 0x19 vendor 0x0 product 0x0 version 0x0
Input device name: "rotary-keys"
Supported events:
  Event type 0 (EV_SYN)
  Event type 2 (EV_REL)
    Event code 0 (REL_X)
Properties:
Testing ... (interrupt to exit)
Event: time 1550141461.594735, type 2 (EV_REL), code 0 (REL_X), value -1
Event: time 1550141461.594735, -------------- SYN_REPORT ------------
Event: time 1550141461.825035, type 2 (EV_REL), code 0 (REL_X), value -1
Event: time 1550141461.825035, -------------- SYN_REPORT ------------
Event: time 1550141462.052871, type 2 (EV_REL), code 0 (REL_X), value -1
Event: time 1550141462.052871, -------------- SYN_REPORT ------------
Event: time 1550141462.199711, type 2 (EV_REL), code 0 (REL_X), value 1
Event: time 1550141462.199711, -------------- SYN_REPORT ------------
Event: time 1550141462.570028, type 2 (EV_REL), code 0 (REL_X), value 1
Event: time 1550141462.570028, -------------- SYN_REPORT ------------
Event: time 1550141464.492574, type 2 (EV_REL), code 0 (REL_X), value 1
Event: time 1550141464.492574, -------------- SYN_REPORT ------------

版权声明：本文为「txfly」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://www.jianshu.com/p/4b207260c62e