超声波测距传感器 (HC-SR04) 在 Raspberry Pi 上给出不一致的读数

Question

我目前正在 raspberry Pi 上研究超声波传感器（和温度，但这对这个问题并不重要），由于 space 限制，我是这样设置的我无法使用面包板。我以前在 Arduino 上使用过超声波传感器，它工作得很好，但我是树莓派和 python 编码的新手，所以如果我的操作有任何问题，请纠正我。

编辑

是的，我确实将电阻器焊接到 Raspberry Pi 上，因为电路板仅用于此功能。

下面是我用来计算距离的脚本，它读取最后 10 个值并计算所述值的平均值。

import RPi.GPIO as GPIO
import time, sys
import statistics 
GPIO.setmode(GPIO.BCM)


log=__import__("logger")

TRIG = 23
ECHO = 24

log.log("Settng up Distance module...","distance.py")

GPIO.setup(TRIG,GPIO.OUT)
GPIO.setup(ECHO,GPIO.IN)
history=[]

total=0
count=0
distance=0
avg=0
dist=[]
distlist=[]
scan=False

GPIO.setmode(GPIO.BCM)
TRIG = 23
ECHO = 24
GPIO.setup(TRIG,GPIO.OUT)
GPIO.setup(ECHO,GPIO.IN)

def status():
    history=[]

    starttime=time.time()
    for i in range(10):
        GPIO.output(TRIG, False)
        time.sleep(0.1)
        #print("Waiting for sensor to settle...")
        #print("Please wait...")

        # ==========
        # GPIO Setup
        # ==========
        GPIO.output(TRIG, True)
        time.sleep(0.00001)
        GPIO.output(TRIG, False)

        #print("Sending...")
        start=time.time()
        pulse_start=start
        while GPIO.input(ECHO)==0 and pulse_start-start<=0.0005:
            pulse_start=time.time()
        if round(pulse_start-start,3)>=0.300:
            print(timeout)
        else:
            #print("Receiving...")
            pulse_end=0
            pulse_duration=0
            while GPIO.input(ECHO)==1 and pulse_duration<2:
                pulse_end=time.time()
                pulse_duration=pulse_end-pulse_start
                #print("Measuring...")

        pulse_duration=pulse_end-pulse_start

        # ====================
        # Calculating Distance
        # ====================
        distance=pulse_duration*17150
        distance=round(distance,2)
        history.append(distance)
    validcount=0
    total=0
    print(history)
    for i in history:
        if i<150:
            validcount+=1
            total+=i
    if validcount>1:
        avg_dist=round(total/validcount,2)
        print("Average distance:",avg_dist)
        if avg_dist<=50:
            return([avg_dist,True,avg_dist,avg_dist])
        else:
            return([avg_dist,False,avg_dist,avg_dist])
    else:
        print("Timeout")
        return([999,False,999,999])
    
while True: print(status()); time.sleep(1)

以下是我站在传感器附近时从传感器获得的读数。

Average distance: -4590081542678.66
[-4590081542678.66, True, -4590081542678.66, -4590081542678.66]
[185.12, 341.6, 17.71, 188.05, 185.94, 185.55, 188.08, 185.58, 184.6, 185.09]
Timeout
[999, False, 999, 999]
[185.58, 186.09, 185.2, 184.4, 185.11, 185.6, 185.56, 186.47, 186.81, 187.24]
Timeout
[999, False, 999, 999]
[187.71, 186.07, 185.59, 185.6, 185.12, 185.61, 185.56, 186.83, 186.41, 184.68]
Timeout
[999, False, 999, 999]
[2243.37, 2245.42, 22.79, 24.57, 2245.48, 2243.77, 2245.33, 2245.12, 2245.18, 2245.28]
Average distance: 23.68
[23.68, True, 23.68, 23.68]
[2244.04, 2246.04, 348.54, 348.56, 348.58, 349.46, 349.44, 348.51, 350.32, 348.05]
Timeout
[999, False, 999, 999]
[348.65, 104.17, 103.76, 100.39, 348.94, 99.49, 348.99, 348.5, 348.14, 348.59]
Average distance: 101.95
[101.95, False, 101.95, 101.95]
[2244.2, 2245.87, 2246.03, 2246.21, 2243.82, 2246.09, 2245.4, 2245.17, 2245.98, 2245.81]
Timeout
[999, False, 999, 999]
[2243.19, 2245.8, 2245.89, 2245.82, 2245.66, 2245.76, 2245.65, 2245.69, 2245.58, 2245.89]
Timeout
[999, False, 999, 999]
[2242.55, 2245.85, 25.14, 24.11, 23.9, 23.2, 2243.35, 2246.04, 2246.33, 2245.93]
Average distance: 24.09
[24.09, True, 24.09, 24.09]
[2243.13, 19.03, 18.33, 17.64, 2246.25, 2244.32, 2245.29, 2245.44, 2245.78, 2246.06]
Average distance: 18.33
[18.33, True, 18.33, 18.33]
[2242.59, 2245.8, 2245.47, 2245.62, 2245.73, 2245.8, 2245.86, 2246.05, 2246.22, 2245.91]
Timeout
[999, False, 999, 999]
[2243.81, 2246.36, 2246.1, 2246.07, 2246.09, 2246.05, 2246.13, 2245.92, 2246.07, 2246.3]
Timeout
[999, False, 999, 999]
[2243.94, 2246.02, 2246.03, 2246.21, 2246.15, 2245.89, 2245.9, 2245.99, 2245.96, 2245.99]
Timeout
[999, False, 999, 999]
[2242.87, 2245.97, 18.78, 17.93, 17.81, 2243.93, 2246.01, 2245.86, 2245.95, 2246.04]
Average distance: 18.17

所以我的程序所做的是从传感器中获取最后 10 位数字并计算列表中该值的平均值，但正如你所看到的，即使我站在它附近，读数也超过了数千的范围.

我知道这个问题距离传感器（HC-SR04）记录不一致的值页面，虽然它确实让我了解了问题，但不幸的是没有解决方案 found.I 我推测问题在于脉冲触发超过 6 秒，导致高值在链接页面中提到，但我不确定这是唯一的问题还是如何解决它。

如果有任何反馈、建议或答复，我将不胜感激。提前谢谢你。

Answer 1

所以在我自己做了一些故障排除后，我发现我的电阻器上的焊料没有正确焊接到 raspberry pi 板上，所以我给它适当的焊料后，它给出了一致的读数现在但高价值的问题没有改变。它仍然会提供高价值，所以我解决这个问题的方法是使用过滤器来过滤掉高价值。

    for i in history:
    if i<150:
        validcount+=1
        total+=i
if validcount>1:
    avg_dist=round(total/validcount,2)
    print("Average distance:",avg_dist)
    if avg_dist<=50:
        return([avg_dist,True,avg_dist,avg_dist])
    else:
        return([avg_dist,False,avg_dist,avg_dist])
else:
    print("Timeout")
    return([999,False,999,999])

并通过加快读取数据的速度。

  for i in range(10):
    GPIO.output(TRIG, False)
    time.sleep(0.1)
    #print("Waiting for sensor to settle...")
    #print("Please wait...")

    # ==========
    # GPIO Setup
    # ==========
    GPIO.output(TRIG, True)
    time.sleep(0.00001) #lowered the delay on the reading
    GPIO.output(TRIG, False)

    #print("Sending...")
    start=time.time()
    pulse_start=start
    while GPIO.input(ECHO)==0 and pulse_start-start<=0.0005:
        pulse_start=time.time()
    if round(pulse_start-start,3)>=0.300:
        print(timeout)
    else:
        #print("Receiving...")
        pulse_end=0
        pulse_duration=0
        while GPIO.input(ECHO)==1 and pulse_duration<2:
            pulse_end=time.time()
            pulse_duration=pulse_end-pulse_start
            #print("Measuring...")

    pulse_duration=pulse_end-pulse_start

    # ====================
    # Calculating Distance
    # ====================
    distance=pulse_duration*17150
    distance=round(distance,2)

这有效地提高了读取速度，如果出现一个有效值，它将忽略所有突然出现的高值。我希望这对遇到同样问题的其他人有所帮助。

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