将重量传感器数据获取到csv文件时出现问题

Question

我刚做了一个覆盆子皮刻度。下面的代码运行良好。皮重完成后，它准确地称出物体的重量，并同时在rasp-pi屏幕上显示时间/日期和权重值。但是，它不会对csv文件做任何操作。列上没有名称，没有数据。奇怪的是，代码运行时没有显示任何错误。能请任何人看看出了什么问题吗？谢谢!宝琳娜

#! /usr/bin/python2
import csv
import datetime
import time

#tare and use the scale
EMULATE_HX711=False

referenceUnit = 1

if not EMULATE_HX711:
    import RPi.GPIO as GPIO
    from hx711 import HX711
else:
    from emulated_hx711 import HX711

def cleanAndExit():
    print("Cleaning...")

    if not EMULATE_HX711:
        GPIO.cleanup()

    print("Bye!")
    sys.exit()

hx = HX711(5, 6)

hx.set_reading_format("MSB", "MSB")

#CALCULATE THE REFFERENCE UNIT
hx.set_reference_unit(1903.3090)

hx.reset()

hx.tare()

print("Tare done! Add weight now...")
#measure weight and write it to csv
while True:
    try:
       # gets the weight. 
        val = hx.get_weight(5)
       # problems here, doesn't write to csv 
        with open('/home/pi/Desktop/sensor2.csv', 'w') as csv_file:
            writer = csv.writer(csv_file)
    # Write a header row with the name of each column.
            writer.writerow(['Time', 'weight'])
    # loop generating new sensor readings every and writing them
    # to the CSV file.
            while True:
        # Make some sensor data.
                reading_time = datetime.datetime.now()
                weight = hx.get_weight(5)   
        # Print out the data and write to the CSV file.
                print('Time: {0} weight: {1}'.format(reading_time, weight))
                writer.writerow([reading_time, weight])
        hx.power_down()
        hx.power_up()
        time.sleep(0.05)

    except (KeyboardInterrupt, SystemExit):
        cleanAndExit()

Answer 1

检查文件夹和文件的权限，因为这可能是问题所在。我在我的RPi 3B+上运行了你的代码(没有缩放部分，见下文)，它工作得很好。确保文件和文件夹都是可写的。我的传感器文件以前并不存在，并且是按预期创建和填充的。这是我测试的：

    #! /usr/bin/python2
    import csv
    import datetime
    import time

    with open('sensor.csv', 'w') as csv_file:
        writer = csv.writer(csv_file)
        writer.writerow(['Time', 'weight'])
        reading_time = datetime.datetime.now()
        weight = 150
        writer.writerow([reading_time, weight])

sensor.csv的内容是：

时间，权重

2020-06-06 04:59:16.840512,150