라즈베리에서 아날로그 신호를 읽어야하는데이 목적으로 MCP3002 회로를 구입했습니다. 올바른 연결로 그것을 연결하고 인터넷을 통해 샘플 코드를 찾았지만 작동하지 않습니다.인터페이스없이 라즈베리의 아날로그 신호 읽기
인터페이스가 있어야하나요, 아니면 인터페이스없이 작업을 수행 할 수 있습니까? 무엇이 잘못 될지 아이디어가 있습니까?
아날로그 입력을 읽는 간단한 코드가 있습니까?
#!/usr/bin/env python
# Written by Limor "Ladyada" Fried for Adafruit Industries, (c) 2015
# This code is released into the public domain
import time
import os
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
DEBUG = 1
# read SPI data from MCP3008 chip, 8 possible adc's (0 thru 7)
def readadc(adcnum, clockpin, mosipin, misopin, cspin):
if ((adcnum > 7) or (adcnum < 0)):
return -1
GPIO.output(cspin, True)
GPIO.output(clockpin, False) # start clock low
GPIO.output(cspin, False) # bring CS low
commandout = adcnum
commandout |= 0x18 # start bit + single-ended bit
commandout <<= 3 # we only need to send 5 bits here
for i in range(5):
if (commandout & 0x80):
GPIO.output(mosipin, True)
else:
GPIO.output(mosipin, False)
commandout <<= 1
GPIO.output(clockpin, True)
GPIO.output(clockpin, False)
adcout = 0
# read in one empty bit, one null bit and 10 ADC bits
for i in range(12):
GPIO.output(clockpin, True)
GPIO.output(clockpin, False)
adcout <<= 1
if (GPIO.input(misopin)):
adcout |= 0x1
GPIO.output(cspin, True)
adcout >>= 1 # first bit is 'null' so drop it
return adcout
# change these as desired - they're the pins connected from the
# SPI port on the ADC to the Cobbler
SPICLK = 18
SPIMISO = 23
SPIMOSI = 24
SPICS = 25
# set up the SPI interface pins
GPIO.setup(SPIMOSI, GPIO.OUT)
GPIO.setup(SPIMISO, GPIO.IN)
GPIO.setup(SPICLK, GPIO.OUT)
GPIO.setup(SPICS, GPIO.OUT)
# 10k trim pot connected to adC#0
potentiometer_adc = 0;
last_read = 0 # this keeps track of the last potentiometer value
tolerance = 5 # to keep from being jittery we'll only change
# volume when the pot has moved more than 5 'counts'
while True:
# we'll assume that the pot didn't move
trim_pot_changed = False
# read the analog pin
trim_pot = readadc(potentiometer_adc, SPICLK, SPIMOSI, SPIMISO, SPICS)
# how much has it changed since the last read?
pot_adjust = abs(trim_pot - last_read)
if DEBUG:
print "trim_pot:", trim_pot
print "pot_adjust:", pot_adjust
print "last_read", last_read
if (pot_adjust > tolerance):
trim_pot_changed = True
if DEBUG:
print "trim_pot_changed", trim_pot_changed
if (trim_pot_changed):
set_volume = trim_pot/10.24 # convert 10bit adc0 (0-1024) trim pot read into 0-100 volume level
set_volume = round(set_volume) # round out decimal value
set_volume = int(set_volume) # cast volume as integer
print 'Volume = {volume}%' .format(volume = set_volume)
set_vol_cmd = 'sudo amixer cset numid=1 -- {volume}% > /dev/null' .format(volume = set_volume)
os.system(set_vol_cmd) # set volume
if DEBUG:
print "set_volume", set_volume
print "tri_pot_changed", set_volume
# save the potentiometer reading for the next loop
last_read = trim_pot
# hang out and do nothing for a half second
time.sleep(0.5)
또한 다음 오류가 나타납니다. RuntimeWarning :이 채널은 이미 사용 중이며 어쨌든 계속됩니다. –
위 코드 중 어떤 줄에서 오류가 발생합니까? 이 코드가 '작동하지 않습니다'라고 말하면 - 더 자세한 정보를 제공하고, 어떤면에서는 작동하지 않습니까? – barny