树莓派-数字温度传感器实验讲解 - 树莓派 - 硬件修炼手册 | Aayu Yain = 学无止境 = 世界上大部分事，都没太大意义。真理与热爱除外

# 接线图

	#include <stdio.h>
	#include <wiringPi.h>
	#include <pcf8591.h>
	#include <math.h>

	#define PCF 120
	#define DOpin 0

	void Print(int x)
	{
	switch(x)
	{
	case 0:
	printf("\n************\n" );
	printf( "* Too Hot! *\n" );
	printf( "************\n\n");
	break;
	case 1:
	printf("\n***********\n" );
	printf( "* Better~ *\n" );
	printf( "***********\n\n");
	break;
	default:
	printf("\n**********************\n" );
	printf( "* Print value error. *\n" );
	printf( "**********************\n\n");
	break;
	}
	}

	int main()
	{
	unsigned char analogVal;
	double Vr, Rt, temp;
	int tmp, status;

	if(wiringPiSetup() == -1){
	printf("setup wiringPi failed !");
	return 1;
	}
	// Setup pcf8591 on base pin 120, and address 0x48
	pcf8591Setup(PCF, 0x48);

	pinMode(DOpin, INPUT);

	status = 0;
	while(1) // loop forever
	{
	printf("loop");
	analogVal = analogRead(PCF + 0);
	Vr = 5 * (double)(analogVal) / 255;
	Rt = 10000 * (double)(Vr) / (5 - (double)(Vr));
	temp = 1 / (((log(Rt/10000)) / 3950)+(1 / (273.15 + 25)));
	temp = temp - 273.15;
	printf("Current temperature : %lf\n", temp);

	// For a threshold, uncomment one of the code for
	// which module you use. DONOT UNCOMMENT BOTH!
	//---------------------------------------------
	// 1. For Analog Temperature module(with DO)
	tmp = digitalRead(DOpin);

	// 2. For Thermister module(with sig pin)
	// if (temp > 33) tmp = 0;
	// else if (temp < 31) tmp = 1;
	//---------------------------------------------

	if (tmp != status)
	{
	Print(tmp);
	status = tmp;
	}

	delay (200);
	}
	return 0;
	}

编译命令： gcc thermistor.c -o thermistor -lwiringPi -lm

	#!/usr/bin/env python
	import PCF8591 as ADC
	import RPi.GPIO as GPIO
	import time
	import math

	DO = 17
	GPIO.setmode(GPIO.BCM)

	def setup():
	ADC.setup(0x48)
	GPIO.setup(DO, GPIO.IN)

	def Print(x):
	if x == 1:
	print ''
	print '***********'
	print '* Better~ *'
	print '***********'
	print ''
	if x == 0:
	print ''
	print '************'
	print '* Too Hot! *'
	print '************'
	print ''

	def loop():
	status = 1
	tmp = 1
	while True:
	analogVal = ADC.read(0)
	Vr = 5 * float(analogVal) / 255
	Rt = 10000 * Vr / (5 - Vr)
	temp = 1/(((math.log(Rt / 10000)) / 3950) + (1 / (273.15+25)))
	temp = temp - 273.15
	print 'temperature = ', temp, 'C'

	# For a threshold, uncomment one of the code for
	# which module you use. DONOT UNCOMMENT BOTH!
	#################################################
	# 1. For Analog Temperature module(with DO)
	#tmp = GPIO.input(DO);
	#
	# 2. For Thermister module(with sig pin)
	if temp > 33:
	tmp = 0;
	elif temp < 31:
	tmp = 1;
	#################################################

	if tmp != status:
	Print(tmp)
	status = tmp

	time.sleep(0.2)

	if __name__ == '__main__':
	try:
	setup()
	loop()
	except KeyboardInterrupt:
	pass

	#!/usr/bin/env python
	#------------------------------------------------------
	#
	# This is a program for PCF8591 Module.
	#
	# Warnng! The Analog input MUST NOT be over 3.3V!
	#
	# In this script, we use a poteniometer for analog
	# input, and a LED on AO for analog output.
	#
	# you can import this script to another by:
	# import PCF8591 as ADC
	#
	# ADC.Setup(Address) # Check it by sudo i2cdetect -y -1
	# ADC.read(channal) # Channal range from 0 to 3
	# ADC.write(Value) # Value range from 0 to 255
	#
	#------------------------------------------------------
	import smbus
	import time

	# for RPI version 1, use "bus = smbus.SMBus(0)"
	bus = smbus.SMBus(1)

	#check your PCF8591 address by type in 'sudo i2cdetect -y -1' in terminal.
	def setup(Addr):
	global address
	address = Addr

	def read(chn): #channel
	if chn == 0:
	bus.write_byte(address,0x40)
	if chn == 1:
	bus.write_byte(address,0x41)
	if chn == 2:
	bus.write_byte(address,0x42)
	if chn == 3:
	bus.write_byte(address,0x43)
	bus.read_byte(address) # dummy read to start conversion
	return bus.read_byte(address)

	def write(val):
	temp = val # move string value to temp
	temp = int(temp) # change string to integer
	# print temp to see on terminal else comment out
	bus.write_byte_data(address, 0x40, temp)

	if __name__ == "__main__":
	setup(0x48)
	while True:
	print 'AIN0 = ', read(0)
	print 'AIN1 = ', read(1)
	tmp = read(0)
	tmp = tmp*(255-125)/255+125 # LED won't light up below 125, so convert '0-255' to '125-255'
	write(tmp)
	# time.sleep(0.3)