Question

目前正在使用3个Raspberry Pi。他们每个人都应该能够用加速度计收集x，y和z。但是，当我在最新的Raspberry Pi上运行以下脚本时出现问题：

#!/usr/bin/python
# -*- coding: utf-8 -*-
# Example on how to read the ADXL345 accelerometer.
# Kim H. Rasmussen, 2014
import sys, math, os, spidev, datetime, ftplib

# Setup SPI
spi = spidev.SpiDev()
#spi.mode = 3    <-- Important: Do not do this! Or SPI won't work as intended, or even at all.
spi.open(0,0)
spi.mode = 3

# Read the Device ID (should be xe5)
id = spi.xfer2([128,0])
print 'Device ID (Should be 0xe5):\n'+str(hex(id[1])) + '\n'

# Read the offsets
xoffset = spi.xfer2([30 | 128,0])
yoffset = spi.xfer2([31 | 128,0])
zoffset = spi.xfer2([32 | 128,0])
accres = 2
accrate = 13
print 'Offsets: '
print xoffset[1]
print yoffset[1]
# print str(zoffset[1]) + "\n\nRead the ADXL345 every half second:"

# Initialize the ADXL345
def initadxl345():
    # Enter power saving state
    spi.xfer2([45, 0])
    # Set data rate to 100 Hz. 15=3200, 14=1600, 13=800, 12=400, 11=200, 10=100 etc.
    spi.xfer2([44, accrate])

    # Enable full range (10 bits resolution) and +/- 16g 4 LSB
    spi.xfer2([49, accres])

    # Enable measurement
    spi.xfer2([45, 8])

# Read the ADXL x-y-z axia
def readadxl345():
    rx = spi.xfer2([242,0,0,0,0,0,0])

    #
    out = [rx[1] | (rx[2] << 8),rx[3] | (rx[4] << 8),rx[5] | (rx[6] << 8)]
    # Format x-axis
    if (out[0] & (1<<16 - 1 )):
        out[0] = out[0] - (1<<16)
#   out[0] = out[0] * 0.004 * 9.82
    # Format y-axis
    if (out[1] & (1<<16 - 1 )):
        out[1] = out[1] - (1<<16)
#   out[1] = out[1] * 0.004 * 9.82
    # Format z-axis
    if (out[2] & (1<<16 - 1 )):
        out[2] = out[2] - (1<<16)
#   out[2] = out[2] * 0.004 * 9.82

    return out

# Initialize the ADXL345 accelerometer
initadxl345()

# Read the ADXL345 every half second
timetosend = 60
while(1):
    with open('/proc/uptime','r') as f: # get uptime
        uptime_start = float(f.readline().split()[0])
    uptime_last = uptime_start
    active_file_first = "S3-" + str(pow(2,accrate)*25/256) + "hz10bit" + str(accres) + 'g' + str(datetime.datetime.utcnow().strftime('%y%m%d%H%M')) $
    active_file = active_file_first.replace(":", ".")
    wStream = open('/var/log/sensor/' + active_file,'wb')
    finalcount = 0
    print "Creating " + active_file
    while uptime_last < uptime_start + timetosend:
        finalcount += 1
        time1 = str(datetime.datetime.now().strftime('%S.%f'))
        time2 = str(datetime.datetime.now().strftime('%M'))
        time3 = str(datetime.datetime.now().strftime('%H'))
        time4 = str(datetime.datetime.now().strftime('%d'))
        time5 = str(datetime.datetime.now().strftime('%m'))
        time6 = str(datetime.datetime.now().strftime('%Y'))
        axia = readadxl345()
        wStream.write(str(round(float(axia[0])/1024,3))+','+str(round(float(axia[1])/1024,3))+','+str(round(float(axia[2])/1024,3))+','+time1+','+ti$
    # Print the reading
    # print axia[0]
    # print axia[1]
    # print str(axia[2]) + '\n'
    # elapsed = time.clock()
    # current = 0
    # while(current < timeout):
    #   current = time.clock() - elapsed
        with open('/proc/uptime', 'r') as f:
                uptime_last = float(f.readline().split()[0])
    wStream.close()

def doftp(the_active_file):
    session = ftplib.FTP('192.0.3.6','sensor3','L!ghtSp33d')
    session.cwd("//datalogger//")
    file = open('/var/log/sensor/' + active_file, 'rb')   # file to send
    session.storbinary('STOR' + active_file, file)        # send the file
    file.close()
    session.quit

当我运行脚本时，我的另外两个Raspberry Pi显示以下内容：

设备ID（应为0xe5）：

为0xE5

偏移：

0

对于我的第三个Raspberry Pi，这应该是相同的，无论在运行脚本之前加速度计的位置如何。但是出于某种原因，我用我的新Raspberry Pi获得了这样的输出：

设备ID（应为0xe5）：

为0x1

偏移：

1

有时它显示完全不同的设备ID和偏移量。

所有3个Raspberry Pi在/etc/modules和/boot/config.txt中都完全相同。

当我同时运行ls /dev/*spi*时，我会获得所有3个Raspberry Pi的/dev/spidev0.0 /dev/spidev0.1。

在Raspberry Pi之间交换MicroSD卡后，很明显该问题与硬件无关。它归结为软件。

这里有人知道我如何解决这个问题吗？事实上它没有显示正确的设备ID和偏移只会使我收集的数据搞砸了并且无用。

ADXL345设备ID和偏移错误（Raspberry Pi）

0 个答案: