树莓派上基于Python编写按键驱动程序

import multiprocessing
import time
import RPi.GPIO as GPIO
import uinput

# 初始化输入GPIO引脚，将引脚拉低
GPIO.setmode(GPIO.BCM) # 使用BCM方式编号
up_pin = 5 # 可对照前文中管脚编号定义
down_pin = 6
left_pin = 13
right_pin = 19
left_button_pin = 20
right_button_pin = 12
GPIO.setup(up_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP) # 将管脚均设置为输入上拉模式
GPIO.setup(down_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(left_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(right_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(left_button_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(right_button_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

# 创建虚拟输入设备（鼠标）
device = uinput.Device([uinput.BTN_LEFT, uinput.BTN_RIGHT, uinput.REL_X, uinput.REL_Y])

XY_STEP = 1 # 用于调节光标的移动步长

# 定义一个通用四向摇杆按键操作的进程处理函数
def direction_key_process(queue, pin, direction):
    while True:
        GPIO.wait_for_edge(pin, GPIO.BOTH) # 该进程Pending等待四向摇杆按键发生动作
        while GPIO.input(pin) == direction: # 如果是有效的低电平，那么它将持续向队列写入管脚编号
            queue.put(pin)
            time.sleep(0.005) # 此延迟可调节光标灵敏度

# 定义一个通用处理左右按键操作的进程
def leftright_key_process(queue, pin):
    while True:
        GPIO.wait_for_edge(pin, GPIO.BOTH) # 该进程Pending等待左/右按键发生动作
        queue.put(pin) # 一旦有状态变化，则将按键编号写入队列

# 定义一个更新光标位置的进程处理函数
def update_position_device():
    while True:
        pin = position_queue.get() # 该进程Pending等待方向按键队列数据
        if pin == up_pin:
            device.emit(uinput.REL_Y, -XY_STEP) # 根据按键方向移动光标XY轴位置
        elif pin == down_pin:
            device.emit(uinput.REL_Y, XY_STEP)
        elif pin == left_pin:
            device.emit(uinput.REL_X, -XY_STEP)
        elif pin == right_pin:
            device.emit(uinput.REL_X, XY_STEP)

# 定义一个更新左右按钮状态的进程处理函数
def update_button_device():
    while True:
        pin = button_queue.get() # 该进程Pending等待左右按键队列数据
        if pin == left_button_pin:
            if GPIO.input(pin) == GPIO.LOW:
                device.emit(uinput.BTN_LEFT, 1) # 按键按下
            else:
                device.emit(uinput.BTN_LEFT, 0) # 按键释放
        elif pin == right_button_pin:
            if GPIO.input(pin) == GPIO.LOW:
                device.emit(uinput.BTN_RIGHT, 1)
            else:
                device.emit(uinput.BTN_RIGHT, 0)

# 为方向按键、左右建分别创建一个队列来保存按键操作的引脚
position_queue = multiprocessing.Queue()
button_queue = multiprocessing.Queue()

# 创建多个进程来处理按键和按钮事件(每个按钮一个进程，互不影响)
processes = [
    multiprocessing.Process(target=direction_key_process, args=(position_queue, up_pin, GPIO.LOW)),
    multiprocessing.Process(target=direction_key_process, args=(position_queue, down_pin, GPIO.LOW)),
    multiprocessing.Process(target=direction_key_process, args=(position_queue, left_pin, GPIO.LOW)),
    multiprocessing.Process(target=direction_key_process, args=(position_queue, right_pin, GPIO.LOW)),
    multiprocessing.Process(target=leftright_key_process, args=(button_queue, left_button_pin)),
    multiprocessing.Process(target=leftright_key_process, args=(button_queue, right_button_pin))
]

# 启动所有进程
for p in processes:
    p.daemon = True # 设置为守护进程，即在主进程结束时自动结束
    p.start()

# 启动两个进程来更新设备状态
update_position_process = multiprocessing.Process(target=update_position_device)
update_position_process.daemon = True # 设置为守护进程，即在主进程结束时自动结束
update_position_process.start()

update_button_process = multiprocessing.Process(target=update_button_device)
update_button_process.daemon = True # 设置为守护进程，即在主进程结束时自动结束
update_button_process.start()

# 等待所有进程结束
for p in processes:
    p.join()

update_position_process.join()
update_button_process.join()

如果运行错误，请执行如下指令

lsmod | grep uinput
sudo modprobe uinput

http://www.etrd.org/2023/05/14/%E6%A0%91%E8%8E%93%E6%B4%BE%E4%B8%8A%E5%9F%BA%E4%BA%8EPython%E7%BC%96%E5%86%99%E6%8C%89%E9%94%AE%E9%A9%B1%E5%8A%A8%E7%A8%8B%E5%BA%8F/

https://www.cnpython.com/qa/1003180

以下是正常代码

import RPi.GPIO as GPIO
import time
from sys import version_info
import uinput
device = uinput.Device([
    uinput.KEY_LEFTSHIFT,
    uinput.KEY_TAB,
    uinput.KEY_SPACE,
    uinput.KEY_LEFTALT
    ])

if version_info.major == 3:
    raw_input = input

# Set up pins
# Rotary A Pin
RoAPin = 17
# Rotary B Pin
RoBPin = 18
# Rotary Switch Pin
RoSPin = 27

def print_message():
    print ("========================================")
    print ("|            Rotary Encoder            |")
    print ("|    ------------------------------    |")
    print ("|        Pin A connect to GPIO17       |")
    print ("|        Pin B connect to GPIO18       |")
    print ("|     Button Pin connect to GPIO27     |")
    print ("|                                      |")
    print ("|         Use a Rotary Encoder         |")
    print ("|     Rotary to add/minus counter      |")
    print ("|      Press to set counter to 0       |")
    print ("|                                      |")
    print ("|                            SunFounder|")
    print ("========================================\n")
    print ("Program is running...")
    print ("Please press Ctrl+C to end the program...")
    #raw_input ("Press Enter to begin\n")

def setup():
    global counter
    global Last_RoB_Status, Current_RoB_Status
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(RoAPin, GPIO.IN)
    GPIO.setup(RoBPin, GPIO.IN)
    GPIO.setup(RoSPin,GPIO.IN, pull_up_down=GPIO.PUD_UP)
    # Set up a falling edge detect to callback clear
    GPIO.add_event_detect(RoSPin, GPIO.FALLING, callback=clear)

    # Set up a counter as a global variable
    counter = 0
    Last_RoB_Status = 0
    Current_RoB_Status = 0

# Define a function to deal with rotary encoder
def rotaryDeal():
    global counter
    global Last_RoB_Status, Current_RoB_Status

    flag = 0
    Last_RoB_Status = GPIO.input(RoBPin)
    # When RoAPin level changes
    while(not GPIO.input(RoAPin)):
        Current_RoB_Status = GPIO.input(RoBPin)
        flag = 1
    if flag == 1:
        # Reset flag
        flag = 0
        if (Last_RoB_Status == 0) and (Current_RoB_Status == 1):
            counter = counter + 1
#            time.sleep(0.5)
            device.emit_combo([
            #    uinput.KEY_LEFTALT,
#                uinput.KEY_LEFTALT,
                uinput.KEY_TAB,
                ])
        if (Last_RoB_Status == 1) and (Current_RoB_Status == 0):
            device.emit_combo([
                uinput.KEY_SPACE,
#                uinput.KEY_TAB,
                ])
            counter = counter - 1
        print ("counter = %d" % counter)

# Define a callback function on switch, to clean "counter"
def clear(ev=None):
    global counter
    counter = 0

def main():
    print_message()
    while True:
        rotaryDeal()

def destroy():
    # Release resource
    GPIO.cleanup()

# If run this script directly, do:
if __name__ == '__main__':
    setup()
    try:
        main()
    # When 'Ctrl+C' is pressed, the child program
    # destroy() will be  executed.
    except KeyboardInterrupt:
        destroy()

实现TAB/SHIFT+TAB键的前进后退

import RPi.GPIO as GPIO
import time
from sys import version_info
import uinput
device = uinput.Device([
    uinput.KEY_LEFTSHIFT,
    uinput.KEY_TAB,
    uinput.KEY_SPACE,
    uinput.KEY_LEFTALT
    ])

if version_info.major == 3:
    raw_input = input

# Set up pins
# Rotary A Pin
RoAPin = 17
# Rotary B Pin
RoBPin = 18
# Rotary Switch Pin
RoSPin = 27

def print_message():
    print ("========================================")
    print ("|            Rotary Encoder            |")
    print ("|    ------------------------------    |")
    print ("|        Pin A connect to GPIO17       |")
    print ("|        Pin B connect to GPIO18       |")
    print ("|     Button Pin connect to GPIO27     |")
    print ("|                                      |")
    print ("|         Use a Rotary Encoder         |")
    print ("|     Rotary to add/minus counter      |")
    print ("|      Press to set counter to 0       |")
    print ("|                                      |")
    print ("|                            SunFounder|")
    print ("========================================\n")
    print ("Program is running...")
    print ("Please press Ctrl+C to end the program...")
    #raw_input ("Press Enter to begin\n")

def setup():
    global counter
    global Last_RoB_Status, Current_RoB_Status
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(RoAPin, GPIO.IN)
    GPIO.setup(RoBPin, GPIO.IN)
    GPIO.setup(RoSPin,GPIO.IN, pull_up_down=GPIO.PUD_UP)
    # Set up a falling edge detect to callback clear
    GPIO.add_event_detect(RoSPin, GPIO.FALLING, callback=clear)

    # Set up a counter as a global variable
    counter = 0
    Last_RoB_Status = 0
    Current_RoB_Status = 0

# Define a function to deal with rotary encoder
def rotaryDeal():
    global counter
    global Last_RoB_Status, Current_RoB_Status

    flag = 0
    Last_RoB_Status = GPIO.input(RoBPin)
    # When RoAPin level changes
    while(not GPIO.input(RoAPin)):
        Current_RoB_Status = GPIO.input(RoBPin)
        flag = 1
    if flag == 1:
        # Reset flag
        flag = 0
        if (Last_RoB_Status == 0) and (Current_RoB_Status == 1):
            counter = counter + 1
#            time.sleep(0.5)
            device.emit_combo([
            #    uinput.KEY_LEFTALT,
#                uinput.KEY_LEFTALT,
                uinput.KEY_TAB,
                ])
        if (Last_RoB_Status == 1) and (Current_RoB_Status == 0):
            device.emit_combo([
                uinput.KEY_LEFTSHIFT,
                uinput.KEY_TAB,
                ])
            counter = counter - 1
#        print ("counter = %d" % counter)

# Define a callback function on switch, to clean "counter"
def clear(ev=None):
    global counter
    counter = 0

def main():
    print_message()
    while True:
        rotaryDeal()

def destroy():
    # Release resource
    GPIO.cleanup()

# If run this script directly, do:
if __name__ == '__main__':
    setup()
    try:
        main()
    # When 'Ctrl+C' is pressed, the child program
    # destroy() will be  executed.
    except KeyboardInterrupt:
        destroy()

一个正常运行的例子，可以移动光标并按下确定按钮

import multiprocessing
import time
import RPi.GPIO as GPIO
import uinput

# 初始化输入GPIO引脚，将引脚拉低
GPIO.setmode(GPIO.BCM) # 使用BCM方式编号
up_pin = 5 # 可对照前文中管脚编号定义
down_pin = 6
left_pin = 13
right_pin = 19
left_button_pin = 20
right_button_pin = 12
GPIO.setup(up_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP) # 将管脚均设置为输入上拉模式
GPIO.setup(down_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(left_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(right_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(left_button_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(right_button_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

# 创建虚拟输入设备（鼠标）
device = uinput.Device([uinput.BTN_LEFT, uinput.BTN_RIGHT, uinput.REL_X, uinput.REL_Y])

XY_STEP = 1 # 用于调节光标的移动步长

# 定义一个通用四向摇杆按键操作的进程处理函数
def direction_key_process(queue, pin, direction):
    while True:
        GPIO.wait_for_edge(pin, GPIO.BOTH) # 该进程Pending等待四向摇杆按键发生动作
        while GPIO.input(pin) == direction: # 如果是有效的低电平，那么它将持续向队列写入管脚编号
            queue.put(pin)
            time.sleep(0.005) # 此延迟可调节光标灵敏度

# 定义一个通用处理左右按键操作的进程
def leftright_key_process(queue, pin):
    while True:
        GPIO.wait_for_edge(pin, GPIO.BOTH) # 该进程Pending等待左/右按键发生动作
        queue.put(pin) # 一旦有状态变化，则将按键编号写入队列

# 定义一个更新光标位置的进程处理函数
def update_position_device():
    while True:
        pin = position_queue.get() # 该进程Pending等待方向按键队列数据
        if pin == up_pin:
            device.emit(uinput.REL_Y, -XY_STEP) # 根据按键方向移动光标XY轴位置
        elif pin == down_pin:
            device.emit(uinput.REL_Y, XY_STEP)
        elif pin == left_pin:
            device.emit(uinput.REL_X, -XY_STEP)
        elif pin == right_pin:
            device.emit(uinput.REL_X, XY_STEP)

# 定义一个更新左右按钮状态的进程处理函数
def update_button_device():
    while True:
        pin = button_queue.get() # 该进程Pending等待左右按键队列数据
        if pin == left_button_pin:
            if GPIO.input(pin) == GPIO.LOW:
                device.emit(uinput.BTN_LEFT, 1) # 按键按下
            else:
                device.emit(uinput.BTN_LEFT, 0) # 按键释放
        elif pin == right_button_pin:
            if GPIO.input(pin) == GPIO.LOW:
                device.emit(uinput.BTN_RIGHT, 1)
            else:
                device.emit(uinput.BTN_RIGHT, 0)

# 为方向按键、左右建分别创建一个队列来保存按键操作的引脚
position_queue = multiprocessing.Queue()
button_queue = multiprocessing.Queue()

# 创建多个进程来处理按键和按钮事件(每个按钮一个进程，互不影响)
processes = [
    multiprocessing.Process(target=direction_key_process, args=(position_queue, up_pin, GPIO.LOW)),
    multiprocessing.Process(target=direction_key_process, args=(position_queue, down_pin, GPIO.LOW)),
    multiprocessing.Process(target=direction_key_process, args=(position_queue, left_pin, GPIO.LOW)),
    multiprocessing.Process(target=direction_key_process, args=(position_queue, right_pin, GPIO.LOW)),
    multiprocessing.Process(target=leftright_key_process, args=(button_queue, left_button_pin)),
    multiprocessing.Process(target=leftright_key_process, args=(button_queue, right_button_pin))
]

# 启动所有进程
for p in processes:
    p.daemon = True # 设置为守护进程，即在主进程结束时自动结束
    p.start()

# 启动两个进程来更新设备状态
update_position_process = multiprocessing.Process(target=update_position_device)
update_position_process.daemon = True # 设置为守护进程，即在主进程结束时自动结束
update_position_process.start()

update_button_process = multiprocessing.Process(target=update_button_device)
update_button_process.daemon = True # 设置为守护进程，即在主进程结束时自动结束
update_button_process.start()

# 等待所有进程结束
for p in processes:
    p.join()

update_position_process.join()
update_button_process.join()

主要代码都做了注释解释，其中关键几点是：

  • 为每个按键都创建了一个进程（非线程），用于检测按键是否有动作；同时还为方向、左右键的动作更新到uinput分别创建了两个进程；使用了两个队列，来建立按键检测进程和uinput更新进程之间的数据通信。
  • 所有进程都要配置为守护进程，使得主进程结束时，可以将所有进程同步结束，否则可能出现Python脚本已退出，但创建的进程还在运行的情况。
  • 所有进程都使用Pending等待的方式等待事件发生（按键检测进程等待IO边沿发生，更新设备状态进程等待队列有数据），才执行代码，以便在无按键动作时尽可能不占用CPU资源

配置开启自启动

若开机自动运行该脚本，则可配置开机自启动。

  1. 将脚本拷贝到/usr目录下在/usr下建立一个pyscript目录，专门存放python脚本，以后调试好的python脚本都放这里1
    cp keydriver_multiprocess.py /usr/pyscript/
  2. 编辑 /etc/rc.local 文件1
    sudo nano /etc/rc.local
    在 exit 0 前添加执行语句1
    2
    3
    4
    5
    6
    ...
    ...

    /usr/bin/python3 /usr/pyscript/keydriver_multiprocess.py

    exit 0
可正常运行的旋转编码器版本
#!/usr/bin/env python
import RPi.GPIO as GPIO
import uinput
device = uinput.Device([
    uinput.KEY_LEFTSHIFT,
    uinput.KEY_TAB,
    uinput.KEY_SPACE
    ])

RoAPin = 17    # CLK Pin
RoBPin = 18    # DT Pin
BtnPin = 27    # Button Pin

globalCounter = 0

flag = 0
Last_RoB_Status = 0
Current_RoB_Status = 0

def setup():
    GPIO.setmode(GPIO.BCM)       # Numbers GPIOs by physical location
    GPIO.setup(RoAPin, GPIO.IN)    # input mode
    GPIO.setup(RoBPin, GPIO.IN)
    GPIO.setup(BtnPin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

def rotaryDeal():
    global flag
    global Last_RoB_Status
    global Current_RoB_Status
    global globalCounter
    Last_RoB_Status = GPIO.input(RoBPin)  
    while(not GPIO.input(RoAPin)):      #未旋转时，GPIO.input(RoAPin)值为1，旋转时会变为0
        Current_RoB_Status = GPIO.input(RoBPin)  #旋转时的当前值
        flag = 1
    if flag == 1:
        flag = 0
        if (Last_RoB_Status == 1) and (Current_RoB_Status == 0):
            globalCounter = globalCounter + 1  #顺时针旋转，角位移增大
            device.emit_combo([uinput.KEY_LEFTSHIFT,uinput.KEY_TAB,])
        if (Last_RoB_Status == 0) and (Current_RoB_Status == 1):
            globalCounter = globalCounter - 1  #逆时针旋转，数值减小
            device.emit_combo([uinput.KEY_TAB,])

def btnISR(channel):
    global globalCounter
    globalCounter = 0
    device.emit_combo([uinput.KEY_SPACE,])

def loop():
    global globalCounter
    tmp = 0 # Rotary Temperary
    GPIO.add_event_detect(BtnPin, GPIO.FALLING, callback=btnISR)
    #当按下按钮时，调用回调函数btnISR
    while True:
        rotaryDeal()
        if tmp != globalCounter:
            print('globalCounter = %d' % globalCounter)
            tmp = globalCounter

def destroy():
    GPIO.cleanup()             # Release resource

if __name__ == '__main__':     # Program start from here
    setup()
    try:
        loop()
    except KeyboardInterrupt:  # When 'Ctrl+C' is pressed, the child program destroy() will be  executed.
        destroy()

sudo nano /etc/rc.local

# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
  printf "My IP address is %s\n" "$_IP"
fi
sudo modprobe uinput
sudo /usr/bin/python3 /home/jack/Downloads/r_gpio_ok_over.py &
exit 0

旋转编码器定稿程序(含正反旋转、空格按键)，开机启动参见上篇

#!/usr/bin/env python
import RPi.GPIO as GPIO
import uinput
device = uinput.Device([
    uinput.KEY_LEFTSHIFT,
    uinput.KEY_TAB,
    uinput.KEY_SPACE
    ])

RoAPin = 17    # CLK Pin
RoBPin = 18    # DT Pin
BtnPin = 27    # Button Pin

globalCounter = 0
flag = 0
BtnFlag = 0
Last_RoB_Status = 0
Current_RoB_Status = 0
Current_Btn_Status = 0

def setup():
    GPIO.setmode(GPIO.BCM)       # Numbers GPIOs by physical location
    GPIO.setup(RoAPin, GPIO.IN)    # input mode
    GPIO.setup(RoBPin, GPIO.IN)
    GPIO.setup(BtnPin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

def rotaryDeal():
    global flag
    global Last_RoB_Status
    global Current_RoB_Status
    global globalCounter
    global BtnFlag
    global Current_Btn_Status
    Last_RoB_Status = GPIO.input(RoBPin)
    while(not GPIO.input(RoAPin)):      #未旋转时，GPIO.input(RoAPin)值为1，旋转时会变为0
        Current_RoB_Status = GPIO.input(RoBPin)  #旋转时的当前值
        flag = 1
    if flag == 1:
        flag = 0
        if (Last_RoB_Status == 1) and (Current_RoB_Status == 0):
            globalCounter = globalCounter + 1  #顺时针旋转，角位移增大
            device.emit_combo([uinput.KEY_LEFTSHIFT,uinput.KEY_TAB,])
        if (Last_RoB_Status == 0) and (Current_RoB_Status == 1):
            globalCounter = globalCounter - 1  #逆时针旋转，数值减小
            device.emit_combo([uinput.KEY_TAB,])
    while(not GPIO.input(BtnPin)):      #未按下按钮时，GPIO.input(BtnPin)值为1，按下时会变为0
        Current_Btn_Status = GPIO.input(BtnPin)  #按下按钮时的当前值
        BtnFlag = 1
    if BtnFlag == 1:
        BtnFlag = 0
        device.emit_combo([uinput.KEY_SPACE])

def btnISR(channel):
    global globalCounter
    globalCounter = 0

def loop():
    global globalCounter
    tmp = 0 # Rotary Temperary
    GPIO.add_event_detect(BtnPin, GPIO.FALLING, callback=btnISR)
    #当按下按钮时，调用回调函数btnISR
    while True:
        rotaryDeal()
        if tmp != globalCounter:
            print('globalCounter = %d' % globalCounter)
            tmp = globalCounter

def destroy():
    GPIO.cleanup()             # Release resource

if __name__ == '__main__':     # Program start from here
    setup()
    try:
        loop()
    except KeyboardInterrupt:  # When 'Ctrl+C' is pressed, the child program destroy() will be  executed.
        destroy()

https://mp.weixin.qq.com/s/ouzEOft6yZ4l0St4kO_79g