水的結冰溫度實驗

[材料]

Arduino主板 x 1

麵包板 x 1

DS18B20防水型溫度感測器 x 1

wifi ESP8266 x 1

步驟一：僅有溫度感測器

[DS18B20防水型溫度感測器 腳位]

紅色線VCC --> arduino 5V

黑色線GND --> arduino GND

藍色線data --> arduino pin2

藍色線data --> 47KΩ的電阻(也可用兩個100KΩ的電阻並聯取代) --> arduino 5V


[DS18B20防水型溫度感測器 函式庫]

https://github.com/milesburton/Arduino-Temperature-Control-Library

https://github.com/adafruit/MAX31850_OneWire

程式碼1 (僅有溫度感測器，數據顯在電腦上)


#include <OneWire.h> 
#include <DallasTemperature.h>
#define ONE_WIRE_BUS 2 
OneWire oneWire(ONE_WIRE_BUS); 
DallasTemperature watersensor(&oneWire);
float watertemp;

void setup() 
{
  Serial.begin(9600); 
  watersensor.begin(); 
}

void loop() { 
  watersensor.requestTemperatures();
  watertemp = watersensor.getTempCByIndex(0);
  Serial.print("Temperature is: "); 
  Serial.print(watertemp); 
  Serial.println(" *C");
  delay(100); 
}

步驟二、溫度感測器 + WIFI模組

注意：WIFI模組要接到3.3V，以免燒壞。

程式碼2 (透過wifi上傳至ThingSpeak)


#include <OneWire.h> 
#include <DallasTemperature.h>
#define ONE_WIRE_BUS 2 
OneWire oneWire(ONE_WIRE_BUS); 
DallasTemperature watersensor(&oneWire);
float watertemp;

#include <SoftwareSerial.h>
SoftwareSerial esp8266(4,5);
String apiKey = "";     // ""內輸入ThingSpeak的Write API Key
String ssid = "";       // ""內輸入wifi基地台的名稱
String password = "";   // ""內輸入wifi基地台的密碼
boolean DEBUG = true;

void showResponse(int waitTime){
    long t=millis();
    char c;
    while (t+waitTime>millis()){
      if (esp8266.available()){
        c=esp8266.read();
        if (DEBUG) Serial.print(c);
      }
    }        
}

boolean thingSpeakWrite(float value1){   //自己增加或減少要上傳的數據項目
  String cmd = "AT+CIPSTART=\"TCP\",\"";
  cmd += "184.106.153.149";
  cmd += "\",80";
  esp8266.println(cmd);
  if (DEBUG) Serial.println(cmd);
  if(esp8266.find("Error")){
    if (DEBUG) Serial.println("AT+CIPSTART error");
    return false;
  }

  String getStr = "GET /update?api_key=";
  getStr += apiKey;

  getStr +="&field1=";
  getStr += String(value1);
  getStr += "\r\n\r\n";

  cmd = "AT+CIPSEND=";
  cmd += String(getStr.length());
  esp8266.println(cmd);
  if (DEBUG)  Serial.println(cmd);
  delay(100);
  esp8266.print(getStr);
  if (DEBUG)  Serial.print(getStr);
  else{
    esp8266.println("AT+CIPCLOSE");
    if (DEBUG)   Serial.println("AT+CIPCLOSE");
    return false;
    }
  return true;
}

 
void setup() 
{
  Serial.begin(9600);
  Serial.println("Arduino...OK");
  esp8266.begin(115200);
  esp8266.write("AT+UART_DEF=9600,8,1,0,0\r\n");
  delay(1500);
  esp8266.begin(9600);
  Serial.println("ESP8266...OK");
  esp8266.println("AT+CWMODE=1");   // set esp8266 as client
  showResponse(1000);  
  esp8266.println("AT+CWJAP=\""+ssid+"\",\""+password+"\"");
  showResponse(10000);  //顯示並等待wifi完成連線 
  watersensor.begin(); 
}

void loop() { 
  watersensor.requestTemperatures();
  watertemp = watersensor.getTempCByIndex(0);
  Serial.print("Temperature is: "); 
  Serial.print(watertemp); 
  Serial.println(" *C");
  
  thingSpeakWrite(watertemp);
  delay(20000);
}