超声波范围传感器 (HC-SR04) 在 Raspberry Pi 上给出不一致的读数

Question

我目前正在我的 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），由于空间限制，我是这样设置的，我无法使用面包板。 我之前在 Arduino 上使用过超声波传感器，它工作得非常好，但我是树莓和 python 编码的新手，所以如果我做的有任何问题，请纠正我。

编辑

是的，我确实将电阻焊接到 Raspberry Pi 上，因为该板仅用于此功能。

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取传感器的最后 10 位数字并计算列表中该值的平均值，但正如您所看到的，即使我站在它附近，读数也超过了数千个。

我知道这个问题距离传感器（HC-SR04）记录不一致的值页面，虽然它确实让我洞察了这个问题，但不幸的是没有找到解决方案。但是我推测问题在于触发过度的脉冲6 秒导致链接页面中提到的高值，但我不确定这是唯一的问题还是如何解决它。

我将不胜感激任何反馈、建议或答案。 先感谢您。

Answer 1

因此，在对我进行了一些故障排除后，我发现我的电阻器上的焊料未正确焊接到 raspberry pi 板上，所以我在给它适当的焊料后，现在给出了一致的读数，但高值问题确实如此没变。 它仍然会提供高价值，所以我为解决这个问题所做的是通过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)

这有效地提供了更快的读取，如果出现一个有效值，它将忽略所有突然的高值。 我希望这有助于其他有同样问题的人。