openmv偶尔发问号，是硬件问题吗，波特率不稳定？

[xhk5]

大多数情况不会。

[xhk5]

好像是有时候发不出

[kidswong999]

如果涉及代码，需要报错提示与全部代码文本，请注意不要贴代码图片

还有具体的现象。

[xhk5]

@kidswong999 没有报错，就是偶尔会发出问号

[kidswong999]

@xhk5 提供具体的代码，和问号的截图

[xhk5]

@kidswong999 # Single Color Code Tracking Example
#
# This example shows off single color code tracking using the OpenMV Cam.
#
# A color code is a blob composed of two or more colors. The example below will
# only track colored objects which have both the colors below in them.

import sensor, image, time, math

# Color Tracking Thresholds (L Min, L Max, A Min, A Max, B Min, B Max)
# The below thresholds track in general red/green things. You may wish to tune them...
#hongse
thresholds1 = [(30, 100, 15, 127, 15, 127),
              (30, 100, -64, -8, -32, 32)]
#lvse
thresholds2=[(59, 37, -67, -21, 22, 49),
            (59, 37, -127, -21, 10, 127)]
#lanse
thresholds3=[(39, 60, -18, -3, -49, -11),
            (0, 100, -18, -3, -49, -11)]




import time
from pyb import UART
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames(time = 2000)
sensor.set_auto_gain(False) # must be turned off for color tracking
sensor.set_auto_whitebal(False) # must be turned off for color tracking
clock = time.clock()
uart = UART(3,115200)
# Only blobs that with more pixels than "pixel_threshold" and more area than "area_threshold" are
# returned by "find_blobs" below. Change "pixels_threshold" and "area_threshold" if you change the
# camera resolution. "merge=True" must be set to merge overlapping color blobs for color codes.
a=0
d=0
b=1
t=0
while(True):
    img = sensor.snapshot().lens_corr(strength = 1.8, zoom = 1.0)
    if t==0 and uart.any():
        m=uart.read(1).decode()
        if m!='o':
            a=int(m)

        clock.tick()



        for blob in img.find_blobs(thresholds1, pixels_threshold=10, area_threshold=10, merge=True):
            if blob.code() == 3: # r/g code == (1 << 1) | (1 << 0)

                img.draw_rectangle(blob.rect())
                img.draw_cross(blob.cx(), blob.cy())
                # Note - the blob rotation is unique to 0-180 only.
                img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=20)

                b=1
                #print(b)
                #print(a)
                print('lse')





        for blob in img.find_blobs(thresholds2, pixels_threshold=10, area_threshold=10, merge=True):
            if blob.code() == 3: # r/g code == (1 << 1) | (1 << 0)

                img.draw_rectangle(blob.rect())
                img.draw_cross(blob.cx(), blob.cy())
                # Note - the blob rotation is unique to 0-180 only.
                img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=20)

                b=3
                #print(b)
                #print(a)
                #print(c)
                print('hse')



        for blob in img.find_blobs(thresholds3, pixels_threshold=10, area_threshold=10, merge=True):
            if blob.code() == 3: # r/g code == (1 << 1) | (1 << 0)

                img.draw_rectangle(blob.rect())
                img.draw_cross(blob.cx(), blob.cy())
                # Note - the blob rotation is unique to 0-180 only.
                img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=20)

                b=5


            print(b)
        if a==b or a==b+1 :
                uart.write("d")

        elif a!=b and b==3:
            uart.write("G")
            uart.write("G")
            n=3

            d=a

            t=1
        elif  a!=b and b==5:
            uart.write("B")

            d=a

            t=1
        else:
            uart.write("d")
        print(t)
        print(a)
        print(b)
        print(d)
    if t==1 and uart.any():
        p=0
        n=uart.read(1).decode()
        if n!='o':
            r=int(n)

        clock.tick()




        for blob in img.find_blobs(thresholds1, pixels_threshold=10, area_threshold=10, merge=True):
            if blob.code() == 3: # r/g code == (1 << 1) | (1 << 0)

                img.draw_rectangle(blob.rect())
                img.draw_cross(blob.cx(), blob.cy())
                # Note - the blob rotation is unique to 0-180 only.
                img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=20)

                p=1
                #print(b)
                #print(a)






        for blob in img.find_blobs(thresholds2, pixels_threshold=10, area_threshold=10, merge=True):
            if blob.code() == 3: # r/g code == (1 << 1) | (1 << 0)

                img.draw_rectangle(blob.rect())
                img.draw_cross(blob.cx(), blob.cy())
                # Note - the blob rotation is unique to 0-180 only.
                img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=20)

                p=3
                #print(b)
                #print(a)
                #print(c)




        for blob in img.find_blobs(thresholds3, pixels_threshold=10, area_threshold=10, merge=True):
            if blob.code() == 3: # r/g code == (1 << 1) | (1 << 0)

                img.draw_rectangle(blob.rect())
                img.draw_cross(blob.cx(), blob.cy())
                # Note - the blob rotation is unique to 0-180 only.
                img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=20)

                p=5

        if p==d or p==d-1:
            uart.write("F")

            t=0

        else:
            uart.write("d")

        print(t)
        print(r)
        print(p)
        print(d)

[xhk5]

大多数情况没问题，但是有时候发不出字母，有时候发问号，尤其发生在和工控机通讯的时候

[xhk5]

[kidswong999]

代码我看了没什么问题，都是发送的字符。
1，检查一下接收端串口的停止位，检验位对不对。
2，检查一下串口线是不是太长了，有时候有干扰。
3，检查一下串口线是不是接触不好。

解决办法：
1，超过10cm使用串口，波特率越高越容易干扰，ttl转成rs232再传输。
2，再软件上自己加入检验。