假如开始是寻迹，我们从单片机或者其他模块给个信号，使得他切换为人脸识别得功能，这个信号怎么给进去，给的是什么信号，代码上需要怎么写对这个信号识别判断的部分，如果需要其他模块连上一起使用，也请告知。

怎们控制巡线代码只执行一段时间，通俗点就是怎们控制某个函数或者语句只执行一段时间？

也就能骗到新手第一次买

from pyb import Pin, Timer
inverse_left=False
inverse_right=False
ain1 =  Pin('P0', Pin.OUT_PP)
ain2 =  Pin('P1', Pin.OUT_PP)
bin1 =  Pin('P2', Pin.OUT_PP)
bin2 =  Pin('P3', Pin.OUT_PP)
ain1.low()
ain2.low()
bin1.low()
bin2.low()
pwma = Pin('P7')
pwmb = Pin('P8')
tim = Timer(4, freq=1000)
ch1 = tim.channel(1, Timer.PWM, pin=pwma)
ch2 = tim.channel(2, Timer.PWM, pin=pwmb)
ch1.pulse_width_percent(0)
ch2.pulse_width_percent(0)
def run(left_speed, right_speed):
	if inverse_left==True:
		left_speed=(-left_speed)
	if inverse_right==True:
		right_speed=(-right_speed)
	if left_speed < 0:
		ain1.low()
		ain2.high()
	else:
		ain1.high()
		ain2.low()
	ch1.pulse_width_percent(abs(left_speed))
	if right_speed < 0:
		bin1.low()
		bin2.high()
	else:
		bin1.high()
		bin2.low()
	ch2.pulse_width_percent(abs(right_speed))

@nzdc 没有报错信息，就是回归直线功能不显示也没效果，小车一直走。。

THRESHOLD = (34, 0, -17, 6, -2, 18) # Grayscale threshold for dark things...
import sensor, image, time
from pyb import LED
import car
from pid import PID
rho_pid = PID(p=0.4, i=0)
theta_pid = PID(p=0.001, i=0)

LED(1).on()
LED(2).on()
LED(3).on()

sensor.reset()
sensor.set_vflip(True)
sensor.set_hmirror(True)
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QQQVGA) # 80x60 (4,800 pixels) - O(N^2) max = 2,3040,000.
#sensor.set_windowing([0,20,80,40])
sensor.skip_frames(time = 2000)     # WARNING: If you use QQVGA it may take seconds
clock = time.clock()                # to process a frame sometimes.

while(True):
    clock.tick()
    img = sensor.snapshot().binary([THRESHOLD])
    line = img.get_regression([(100,100,0,0,0,0)], robust = True)
    if (line):
        rho_err = abs(line.rho())-img.width()/2
        if line.theta()>90:
            theta_err = line.theta()-180
        else:
            theta_err = line.theta()
        img.draw_line(line.line(), color = 127)
        print(rho_err,line.magnitude(),rho_err)
        if line.magnitude()>8:
            #if -40<b_err<40 and -30<t_err<30:
            rho_output = rho_pid.get_pid(rho_err,1)
            theta_output = theta_pid.get_pid(theta_err,1)
            output = rho_output+theta_output
            car.run(50+output, 50-output)
        else:
            car.run(0,0)
    else:
        car.run(50,-50)
        pass
    #print(clock.fps())

还有car.py和pid.py文件导入可试