树莓派（九）：多线程基础+控制多台电机

0 前言

多线程再平时的树莓派中将会非常广泛——比如控制多个电机同时运动等等
莫凡大神视频地址大神视频教学链接

1 基础

线程开始就是这一步完成，继续下一步，与此同时，分出了一个支线，并且开始支线

import threading
import time

def job():
    print('T1 start\n')
    for i  in range(10):
        time.sleep(0.1)
    print('T1 finish\n')
    #print('number:%s'%threading.current_thread())

def T2():
    print('T2 start\n')
    print('T2 finish\n')
    
def main():
    for i in range(4):
        add_thread = threading.Thread(target=job,name = 'T1')
        #启动线程1来运行job函数
        add_thread2 = threading.Thread(target=T2,name = 'T2')
        #启动线程2来运行T2函数
        add_thread.start()
        #add_thread启动
        add_thread2.start()
        #add_thread2启动
    add_thread.join()
    #join当add_thread完成后再执行以下操作
    print('all done\n')
        #print(threading.active_count())
        #print(threading.enumerate())
        #print(threading.current_thread())
main()

import threading
import time
from queue import Queue
#queue可以让多线程函数有返回值

def job(l,p):
    for i in range(len(l)):
        l[i] = l[i]**2
        print('job start\n')
    print('job finshed\n')
    p.put(l)
    #将q放入列表l当中
def mul():
    q = Queue()
    #Queue---放入返回值
    thrads = []
    data =  [[1,2,3],[4,5,6],[7,8,9],[4,5,8]]
    for i in range(4):
        #这里用于开启多4个线程分别运算data[i]
        t = threading.Thread(target = job,args = (data[i],q))
        #对已经开启的线程进行传参数（data[i],q）
        #创建线程
        print(t)
        t.start()
        #开始第i线程 继续往下走
        thrads.append(t)
    for f in thrads:
        f.join()
        print('wancheng???')
        #等第i个线程结束了继续往下走

    results = []

    for t in range(4):
        results.append(q.get())
        #q.get()从q中读取一个值（只有按顺序拿出一个）
        print('append')
    print(results)

mul()

2 控制两台电机

说明：设计了一个class，用来直接调用motor模块进行控制，减小代码量，减小读者阅读难度

import RPi.GPIO as GPIO
import time
import threading
#指定第一个电机的GPIO口
IN1 = 40    # pin40
IN2 = 38
IN3 = 36
IN4 = 35
#指定第二个电机的GPIO口
IN5 = 18
IN6 = 16
IN7 = 13
IN8 = 15
#设置两台电机的频率和步数
motor1_delay = 0.0002
motor1_steps = 4000
motor2_delay = 0.02
motor2_steps = 400
#定义电机的类
class Motor:
    def __init__(self,I1,I2,I3,I4):
    #初始化类的参数
        self.I1 = I1
        self.I2 = I2
        self.I3 = I3
        self.I4 = I4
        GPIO.setwarnings(False)
        GPIO.setmode(GPIO.BOARD)      # 设置寻址模式，按照pin引脚寻址
        GPIO.setup(self.I1, GPIO.OUT)      # 指定IN1输出
        GPIO.setup(self.I2, GPIO.OUT)
        GPIO.setup(self.I3, GPIO.OUT)
        GPIO.setup(self.I4, GPIO.OUT)

    def loop(self,delay_loop,steps_loop):
        print ("backward...")
        Motor.backward(self,delay_loop,steps_loop)

        print ("stop...")
        Motor.stop(self)                 # stop
        time.sleep(3)          # sleep 3s

        print ("forward...")
        Motor.forward(self,delay_loop,steps_loop)

        print ("stop...")
        Motor.stop(self)
        time.sleep(3)

    def setStep(self, w1, w2, w3, w4):
        #GPIO.output（）---指定脚位输出high还是low
        GPIO.output(self.I1, w1)#.output（in1，1）代表指定IN1引脚输出的是高电平，0就是低电平
        GPIO.output(self.I2, w2)
        GPIO.output(self.I3, w3)
        GPIO.output(self.I4, w4)

    def backward(self, delay, steps):
        for i in range(0, steps):
            Motor.setStep(self,1, 0, 0, 1)
            time.sleep(delay)
            Motor.setStep(self,0, 1, 0, 1)
            time.sleep(delay)
            Motor.setStep(self,0, 1, 1, 0)
            time.sleep(delay)
            Motor.setStep(self,1, 0, 1, 0)
            time.sleep(delay)
            
    def forward(self,delay, steps):  
        for i in range(0, steps):
            Motor.setStep(self,1, 0, 1, 0)
            time.sleep(delay)
            Motor.setStep(self,0, 1, 1, 0)
            time.sleep(delay)
            Motor.setStep(self,0, 1, 0, 1)
            time.sleep(delay)
            Motor.setStep(self,1, 0, 0, 1)
            time.sleep(delay)

    def stop(self):
        Motor.setStep(self,0, 0, 0, 0)

def destroy():
    GPIO.cleanup()

if __name__ == '__main__':  #主函数测试   
    motor1 = Motor(IN1,IN2,IN3,IN4)#实例化类
    #motor1.setup(IN1,IN2,IN3,IN4)
    motor2 = Motor(IN5,IN6,IN7,IN8)#实例化类
    #motor2.setup(IN5,IN6,IN7,IN8)

    try:
        while True:
            shuru = int(input('input:'))
            if shuru ==1:
                thread1 = threading.Thread(target=motor1.loop,
                                           args=(motor1_delay,motor1_steps))#创建线程1
                thread2 = threading.Thread(target=motor2.loop,
                                           args=(motor2_delay,motor2_steps))#创建线程2
                thread1.start()#开始线程1
                thread2.start()#开始线程2

    except KeyboardInterrupt:  # When 'Ctrl+C' is pressed, the child function destroy() will be  executed.
        destroy()

3 时间控制

import time
import threading

def thread1():
    start = time.time()
    for i in range(10):
        end = time.time()
        t = end - start
        if t < 2:
            print('辅助线程%d\n',i)
            time.sleep(1)
        else:
            break
    
def main():
    for j in range(50):
        add_thread = threading.Thread(target=thread1,name = 'T1')
        add_thread.start()
        #print('主线程%d\n',j)
        time.sleep(2)
        print(threading.active_count())
main()