ThingSpeak

ESP8266 對 Access Point(寬頻分享器)而言為 Station
api.thingspeak.com 為HTTP Server ESP8266為Client

ThingSpeak stores data in channels. Channels support an unlimited number of timestamped observations (think of these as rows in a spreadsheet). Each channel has up to 8 fields (think of these as columns in a speadsheet).

Channels may be public, where anyone can see the data,
or private, where only the owner and select users can read the data.

Each channel has an associated Write API Key that is used to control who can write to a channel.
In addition, private channels have one or more Read API Keys to control who can read from private channel.
An API Key is not required to read from public channels.
Each channel can have up to 8 fields.
One field is created by default.

1channel 最多可有 8個 Field
public channel :Write API Key
private channel:Write API Key ,Read API Key

ThingSpeak有提供免費、非商業用途的IoT雲端服務，使用此免費方案時，物聯網裝置的訊息發送時間間隔不可小於15秒、每年可發送300萬則訊息（每一天約8200則）。

ThingSpeak平台的資料儲存空間叫做Channel（通道），每次上傳的資料最多能有8個欄位（field）。例如，從控制板送出溫度和濕度資料，就需要「溫度」和「濕度」兩個欄位。

ThingSpeak提供前端兩種上傳資料的方式：
REST：透過GET或POST的HTTP協定上傳資料。
MQTT：使用輕量的通訊協定上傳資料。

ThingSpeak 申請帳號

#include <ThingSpeak.h>
#include <ESP8266WiFi.h>

//---------------- Fill in your credentails   ---------------------
char ssid[] = "RouterSSID";
char pass[] = "RouterPassword";
unsigned long channelID =10*****84;
const char * myWriteAPIKey = "CP********EY";
//------------------------------------------------------------------

WiFiClient client;

int value = 0;

void setup() {
//Initialize serial and wait for port to open:
Serial.begin(115200);
while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
}

WiFi.mode(WIFI_STA);
ThingSpeak.begin(client);
}

void loop() {

// Connect or reconnect to WiFi
if(WiFi.status() != WL_CONNECTED){
    Serial.println("");
    Serial.print("Attempting to connect to SSID: ");
    Serial.print(ssid);
    while(WiFi.status() != WL_CONNECTED){
      WiFi.begin(ssid, pass);
      Serial.print(".");
      delay(5000);
    }
    Serial.println("\nConnected.");
}

// Write to ThingSpeak. There are up to 8 fields in a channel, allowing you to store up to 8 different
// pieces of information in a channel. Here, we write to field 1.
int x = ThingSpeak.writeField(channelID, 1, value, myWriteAPIKey);

// Check the return code
if(x == 200){
    Serial.println("Channel update successful.");
}
else{
    Serial.println("Problem updating channel. HTTP error code " + String(x));
}

value++;
if(value > 99){
    value = 0;
}

delay(20000); // Wait 20 seconds before sending a new value
}

DHT11

ESP-01S DHT11 v1.0

Create a new channel

https://thingspeak.com
https://thingspeak.com/channels/491085

1. 使用ThingSpeak.h---Write, Read
2. 使用ESP8266HTTPClient.h---GET, POST
3. 使用ESP8266WiFi.h ----GET , POST

1. 使用ThingSpeak library
ThingSpeak Library(gitHub)(.zip)
請先下載安裝Library

#include <DHTesp.h>
#include <ThingSpeak.h>
#include <ESP8266WiFi.h>
//*-- IoT Information
#define SSID    "Router SSID"
#define PASS    "Router Password"
//----------- Channel details ----------------//
unsigned long Channel_ID = xxxxx; // Your Channel ID
#define myWriteAPIKey "xxxxxxxxxxx" //Your write API key
//-------------------------------------------//

#define Field_Number_1 1
#define Field_Number_2 2

DHTesp dht;
WiFiClient client;

float temperature, humidity;
void setup() {
   dht.setup(2, DHTesp::DHT11);
    Serial.begin( 115200 );
    Serial.println( "ESP8266 Ready!" );
    ThingSpeak.begin(client);
    // Connecting to a WiFi network
    Serial.print("Connect to ");
    Serial.println( SSID );
    WiFi.begin( SSID, PASS );
    while( WiFi.status() != WL_CONNECTED )
    {
        delay(500);
        Serial.print( "." );
    }
    Serial.println( "" );

    Serial.println( "WiFi connected" );
    Serial.println( "IP address: " );
    Serial.println( WiFi.localIP() );
    Serial.println( "" );


}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();

    // 確認取回的溫溼度數據可用
    if( isnan( humidity ) || isnan( temperature ) )
    {
        Serial.println( "Failed to read form DHT11" );
    return;
    }
    else
    {
        // DHT11 溫度與濕度傳送
        Serial.print( "Humidity: " );
        Serial.print( humidity );
        Serial.print( ", Temperature: " );
        Serial.println( temperature );
        updateDHT11();
    }
}

void updateDHT11()
{

ThingSpeak.writeField(Channel_ID, Field_Number_1, String((int)temperature), myWriteAPIKey);
delay(15000);
ThingSpeak.writeField(Channel_ID, Field_Number_2, String((int)humidity), myWriteAPIKey);
delay(15000);

}

測試完成刪除 Serial 部分
ESP01S 直接插入DH11模組

//移除Serial

#include <DHTesp.h>
#include <ThingSpeak.h>
#include <ESP8266WiFi.h>
//*-- IoT Information
#define SSID    "Router SSID"
#define PASS    "Router Password"
//----------- Channel details ----------------//
unsigned long Channel_ID = xxxxx; // Your Channel ID
#define myWriteAPIKey "xxxxxxxxxxx" //Your write API key
//-------------------------------------------//

#define Field_Number_1 1
#define Field_Number_2 2

DHTesp dht;
WiFiClient client;

float temperature, humidity;
void setup() {
   dht.setup(2, DHTesp::DHT11);
   ThingSpeak.begin(client);
    WiFi.begin( SSID, PASS );
    while( WiFi.status() != WL_CONNECTED )
    {   delay(500);     }
}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();

    // 確認取回的溫溼度數據可用
    if( isnan( humidity ) || isnan( temperature ) )
    {   return;    }
    else
    {   updateDHT11();    }
}

void updateDHT11()
{

ThingSpeak.writeField(Channel_ID, Field_Number_1, String((int)temperature), myWriteAPIKey);
delay(15000);
ThingSpeak.writeField(Channel_ID, Field_Number_2, String((int)humidity), myWriteAPIKey);
delay(15000);

}

Read From Thingspeak
ThingSpeak Library(gitHub)(.zip)
請先下載安裝Library

#include "ThingSpeak.h"
#include <ESP8266WiFi.h>
#define ssid "xxxxx" // your network SSID (name)
#define pass "xxxxxxxx"   // your network password
//---------Channel Details---------//
unsigned long counterChannelNumber = 12345;   // Channel ID
#define myCounterReadAPIKey "CHXEV2VDBJ" // Read API Key
#define FieldNumber1 1 // The field you wish to read
#define FieldNumber2 2 // The field you wish to read
//-------------------------------//
int statusCode;
WiFiClient client;
void setup()
{
Serial.begin(115200);
WiFi.mode(WIFI_STA);
ThingSpeak.begin(client);
}

void loop()
{
//----------------- Network -----------------//
if (WiFi.status() != WL_CONNECTED)
{
    Serial.print("Connecting to ");
    Serial.print(ssid);
    Serial.println(" ....");
    while (WiFi.status() != WL_CONNECTED)
    {
      WiFi.begin(ssid, pass);
      delay(5000);
    }
    Serial.println("Connected to Wi-Fi Succesfully.");
}
//--------- End of Network connection--------//

//---------------- Channel 1 ----------------//
long temp = ThingSpeak.readLongField(counterChannelNumber, FieldNumber1, myCounterReadAPIKey);
statusCode = ThingSpeak.getLastReadStatus();
if (statusCode == 200)
{
    Serial.print("Temperature: ");
    Serial.println(temp);
}
else
{
    Serial.println("Unable to read channel / No internet connection");
}
delay(100);
//-------------- End of Channel 1 -------------//

//---------------- Channel 2 ----------------//
long humidity = ThingSpeak.readLongField(counterChannelNumber, FieldNumber2, myCounterReadAPIKey);
statusCode = ThingSpeak.getLastReadStatus();
if (statusCode == 200)
{
    Serial.print("Humidity: ");
    Serial.println(humidity);
}
else
{
    Serial.println("Unable to read channel / No internet connection");
}
delay(20000);
//-------------- End of Channel 2 -------------//
}

https://api.thingspeak.com/channels/935349/feeds.json?results=1
https://api.thingspeak.com/channels/935349/feeds.xml?results=1
https://api.thingspeak.com/channels/935349/feeds.csv?results=1
935349 為channel ID
read data(web)

2. 使用 ESP8266HTTPClient.h

//Example 2.1 使用範例
#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#define SSID    "ampTony"
#define PASS    "123456789A"

void setup() {

    Serial.begin( 115200 );
    Serial.println( "ESP8266 Ready!" );
    // Connecting to a WiFi network
    Serial.print("Connect to ");
    Serial.println( SSID );
    WiFi.begin( SSID, PASS );
    while( WiFi.status() != WL_CONNECTED )
    {
        delay(500);
        Serial.print( "." );
    }
    Serial.println( "" );
    Serial.println( "WiFi connected" );
    Serial.println( "IP address: " );
    Serial.println( WiFi.localIP() );
    Serial.println( "" );
}

void loop() {
   if (WiFi.status() == WL_CONNECTED) {
    WiFiClient client;
    HTTPClient http;

    Serial.print("[HTTP] begin...\n");

    if (http.begin(client, "http://iot.ntue.edu.tw/EL/ESP8266/httpClientTest.html")) {
      Serial.print("[HTTP] GET...\n");
      // start connection and send HTTP header
      int httpCode = http.GET();

      // httpCode will be negative on error
      if (httpCode > 0) {
        // HTTP header has been send and Server response header has been handled
        Serial.printf("[HTTP] GET... code: %d\n", httpCode);

        // file found at server
        if (httpCode == HTTP_CODE_OK || httpCode == HTTP_CODE_MOVED_PERMANENTLY)
       {
          String payload = http.getString();
          Serial.println(payload);
        }
      } else { Serial.printf("[HTTP] GET... failed, error:%s\n",http.errorToString(httpCode).c_str()); }

      http.end();
    } else {
      Serial.printf("[HTTP} Unable to connect\n");
    }
}

delay(10000);
}

//Example 2.2
#include <ESP8266HTTPClient.h>
HTTPClient _httpClient;

UrlString = String("http://api.thingspeak.com/update?api_key=XXXX") + "&field1=" + String((int)temperature) +
                              "&field2=" + String((int)humidity);//XXXX替換為你的APIKeys

_httpClient.begin(UrlString);
int httpCode = _httpClient.GET();            //Send the request

String payload = _httpClient.getString();    //Get the response payload
Serial.println(httpCode);   //Print HTTP return code
Serial.println(payload);    //Print request response payload

_httpClient.end(); //Close connection
delay(15000);

//Example 2.3
//使用ESP8266HTTPClient GET
#include <DHTesp.h>
#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#define wKey    "LSODUBHEK01D9JA0"
DHTesp dht;

//*-- IoT Information
#define mSSID    "RouterSSID"
#define PASS    "RouterPWD"
String UrlString;//thingSpeak網站傳送get請求的url
HTTPClient _httpClient;

int _httpGET(String url) {
_httpClient.end();
_httpClient.begin(url);
return _httpClient.GET();
}

float temperature, humidity;
void setup() {
   dht.setup(2, DHTesp::DHT11);
    Serial.begin( 115200 );
    Serial.println( "ESP8266 Ready!" );
    // Connecting to a WiFi network
    Serial.print("Connect to ");
    Serial.println( mSSID );
    WiFi.begin( mSSID, PASS );
    while( WiFi.status() != WL_CONNECTED )
    {
        delay(500);
        Serial.print( "." );
    }
    Serial.println( "" );

    Serial.println( "WiFi connected" );
    Serial.println( "IP address: " );
    Serial.println( WiFi.localIP() );
    Serial.println( "" );

}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();

    // 確認取回的溫溼度數據可用
    if( isnan( humidity ) || isnan( temperature ) )
    {
        Serial.println( "Failed to read form DHT11" );
    return;
    }
    else
    {
        // DHT11 溫度與濕度傳送
        Serial.print( "Humidity: " );
        Serial.print( humidity );
        Serial.print( ", Temperature: " );
        Serial.println( temperature );
        updateDHT11();
    }
}

void updateDHT11()
{

UrlString = String("http://api.thingspeak.com/update?api_key=") +wKey+"&field1="+String((int)temperature)+"&field2="+String((int)humidity);

if (_httpGET(UrlString) > 0) {
    delay(15000); //thinkSpeak網站限制上傳頻率所以這裡延時15s
}
}

//Example 2.4
//ESP8266HTTPClient GET
//移除Serial
#include <DHTesp.h>
#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#define wKey    "LSODUBHEK01D9JA0"
DHTesp dht;

//*-- IoT Information
#define mSSID    "RouterSSID"
#define PASS    "RouterPWD"
String UrlString;//thingSpeak網站傳送get請求的url
HTTPClient _httpClient;

int _httpGET(String url) {
_httpClient.end();
_httpClient.begin(url);
return _httpClient.GET();
}

float temperature, humidity;
void setup() {
   dht.setup(2, DHTesp::DHT11);
    WiFi.begin( mSSID, PASS );
    while( WiFi.status() != WL_CONNECTED )
    { delay(500); }
}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();

    // 確認取回的溫溼度數據可用
    if( isnan( humidity ) || isnan( temperature ) )
    { return; }
    else
    {
        // DHT11 溫度與濕度傳送
        updateDHT11();
    }
}

void updateDHT11()
{

UrlString = String("http://api.thingspeak.com/update?api_key=") +wKey+"&field1="+String((int)temperature)+"&field2="+String((int)humidity);

if (_httpGET(UrlString) > 0) {
    delay(15000); //thinkSpeak網站限制上傳頻率所以這裡延時15s
}
}

//Example 2.5
//ESP8266HTTPClient POST
#include <DHTesp.h>
#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#define SSID    "Router SSID"
#define PASS    "Router PassWord"
#define url "http://api.thingspeak.com/update/"
#define THING_SPEAK_WRITE_API_KEY "Your Write API KEY"
DHTesp dht;
HTTPClient _httpClient;
String params;
float temperature, humidity;
void setup() {
    dht.setup(2, DHTesp::DHT11);
    WiFi.begin( SSID, PASS );
    while( WiFi.status() != WL_CONNECTED )
    { delay(500);}
    Serial.println("WiFi connected");

}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();

    // 確認取回的溫溼度數據可用
    if( isnan( humidity ) || isnan( temperature ) )
    {

    return;
    }
    else
    {
        // DHT11 溫度與濕度傳送
         updateDHT11();
    }
}

void updateDHT11()
{

params = "field1=" + String((int)temperature)+"&field2=" + String((int)humidity);
_httpClient.begin(url);
_httpClient.addHeader("X-THINGSPEAKAPIKEY", THING_SPEAK_WRITE_API_KEY);
_httpClient.addHeader("Content-Type", "application/x-www-form-urlencoded");
if (_httpClient.POST(params)) {
   delay(15000); //thinkSpeak網站限制上傳頻率所以這裡延時15s
}
    _httpClient.end();
}

Documentation
ESP8266HTTPClient(GitHub)

3. 使用ESP8266WiFi.h ----GET , POST

Client

HTTP get
Client request

GET /index.html HTTP/1.1
Host: www.example.com

client.print("GET /index.html" + " HTTP/1.1\r\n" )
client.print("Host:www.example.com\r\n")
client.print("Connection: close\r\n\r\n")

A client request (consisting in this case of the request line and only one header field) is followed by a blank line, so that the request ends with a double newline, each in the form of a carriage return followed by a line feed.

The "Host" field distinguishes between various DNS names sharing a single IP address, allowing name-based virtual hosting.
While optional in HTTP/1.0, it is mandatory in HTTP/1.1.

Request the Data
If connection is successful, we should send request the host to provide specific information we need. This is done using the HTTP GET request as in the following lines:

client.print("GET /index.html" + " HTTP/1.1\r\n" )
client.print("Host:www.example.com\r\n")
client.print("Connection: close\r\n")
client.print("\r\n");

Read Reply from the Server
Then, while connection by our client is still alive (while (client.connected()), see below) we can read line by line and print out server’s response:

while (client.connected())
{
if (client.available())
{
String line = client.readStringUntil('\n');
Serial.println(line);
}
}
The inner if (client.available()) is checking if there are any data available from the server. If so, then they are printed out.

Once server sends all requested data it will disconnect and program will exit the while loop.

使用WiFiClient

ESP8266Wifi gives raw access to wifi functions independent of the protocol you are going to use.

WifiClient can send and receive data to a server but you have to format the data yourself e.g. message headers and parsing the response.

ESP8266HTTPClient specifically knows how to communicate with a http web server and does all the formatting and parsing needed.

If you are making http requests like GET or POST then it is normally best to use the ESP8266HTTPClient to keep the application code simpler and to benefit from the tried and tested HTTP handling.

//Example 3.1
//使用WiFiClient GET
#include <DHTesp.h>
#include <ESP8266WiFi.h>
DHTesp dht;

//*-- IoT Information
#define SSID    "路由器名稱"
#define PASS    "路由器連線密碼"
#define HOST    "api.thingspeak.com" // ThingSpeak IP Address: 184.106.153.149
#define PORT    80
String writeAPIKey="LSXXXXXXXXXXJA0"; // 換上自己的 Write API Key

// 設定 ESP8266 作為 Client 端
WiFiClient client;
float temperature, humidity;
void setup() {
   dht.setup(2, DHTesp::DHT11);
    Serial.begin( 115200 );
    Serial.println( "ESP8266 Ready!" );
    // Connecting to a WiFi network
    Serial.print("Connect to ");
    Serial.println( SSID );
    WiFi.begin( SSID, PASS );
//因不需由外部連入使用Router分配動態IP即可
    // 持續等待並連接到指定的 WiFi SSID
    while( WiFi.status() != WL_CONNECTED )
    {
        delay(500);
        Serial.print( "." );
    }
    Serial.println( "" );

    Serial.println( "WiFi connected" );
    Serial.println( "IP address: " );
    Serial.println( WiFi.localIP() );
    Serial.println( "" );


}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();

    // 確認取回的溫溼度數據可用
    if( isnan( humidity ) || isnan( temperature ) )
    {
        Serial.println( "Failed to read form DHT11" );
    return;
    }
    else
    {
        // DHT11 溫度與濕度傳送
        Serial.print( "Humidity: " );
        Serial.print( humidity );
        Serial.print( ", Temperature: " );
        Serial.println( temperature );
        updateDHT11();
    }

    // 每隔多久傳送一次資料
    delay( 20000 ); // 20 second
}

void updateDHT11()
{

    if( !client.connect( HOST, PORT ) )
    {
        Serial.println( "connection failed" );
        return;
    }
    else
    {
        // 準備上傳到 ThingSpeak IoT Server 的資料
        // 已經預先設定好 ThingSpeak IoT Channel 的欄位
        // field1：溫度；field2：濕度
       /*
           使用 GET 傳送資料的格式
          GET /update?key=[THINGSPEAK_KEY]&field1=[data 1]&filed2=[data 2]...;
      */
        String getStr = "GET /update?key="+ writeAPIKey +
                              "&field1=" + String((int)temperature) +
                              "&field2=" + String((int)humidity) +
                              " HTTP/1.1\r\n";
        client.print( getStr );
        client.print( "Host: api.thingspeak.com\r\n" );
        client.print( "Connection: close\r\n\r\n" );

        delay(10);
        //
        // 處理遠端伺服器回傳的訊息，程式碼可以寫在這裡！
        //
        client.stop();
    }
}

//Example 3.2
//使用WiFiClient GET
#include <DHTesp.h>
#include <ESP8266WiFi.h>
DHTesp dht;

//*-- IoT Information
#define SSID    "路由器名稱"
#define PASS    "路由器連線密碼"
#define HOST    "api.thingspeak.com" // ThingSpeak IP Address: 184.106.153.149
#define PORT    80
String writeAPIKey="LSXXXXXXXXXXJA0"; // 換上自己的 Write API Key

WiFiClient client;
float temperature, humidity;
void setup() {
   dht.setup(2, DHTesp::DHT11);
   WiFi.begin( SSID, PASS );
}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();
    updateDHT11();
    delay( 20000 ); // 20 second
}

void updateDHT11()
{
      client.connect( HOST, PORT );
     String getStr = "GET /update?key="+ writeAPIKey +
                              "&field1=" + String((int)temperature) +
                              "&field2=" + String((int)humidity) +
                              " HTTP/1.1\r\n";
        client.print( getStr );
        client.print( "Host: api.thingspeak.com\r\n" );
        client.print( "Connection: close\r\n\r\n" );
        delay(10);
        client.stop();
   }

//Example 3.3
//使用WiFiClient POST
#include <DHTesp.h>
#include <ESP8266WiFi.h>
DHTesp dht;
//*-- IoT Information
#define SSID    "Router SSID"
#define PASS    "Router Password"
#define HOST    "api.thingspeak.com" // ThingSpeak IP Address: 184.106.153.149
#define PORT    80
String APIKEY = "Your Write Key";
WiFiClient client;
float temperature, humidity;
void setup() {
   dht.setup(2, DHTesp::DHT11);
    Serial.begin( 115200 );
    Serial.println( "ESP8266 Ready!" );
    // Connecting to a WiFi network
    Serial.print("Connect to ");
    Serial.println( SSID );
    WiFi.begin( SSID, PASS );
//因不需由外部連入使用Router分配動態IP即可
    // 持續等待並連接到指定的 WiFi SSID
    while( WiFi.status() != WL_CONNECTED )
    {
        delay(500);
        Serial.print( "." );
    }
    Serial.println( "" );

    Serial.println( "WiFi connected" );
    Serial.println( "IP address: " );
    Serial.println( WiFi.localIP() );
    Serial.println( "" );

}

void loop() {
    humidity= dht.getHumidity();
    temperature = dht.getTemperature();

    // 確認取回的溫溼度數據可用
    if( isnan( humidity ) || isnan( temperature ) )
    {
        Serial.println( "Failed to read form DHT11" );
    return;
    }
    else
    {
        // DHT11 溫度與濕度傳送
        Serial.print( "Humidity: " );
        Serial.print( humidity );
        Serial.print( ", Temperature: " );
        Serial.println( temperature );
        updateDHT11();
    }

    // 每隔多久傳送一次資料
    delay( 20000 ); // 20 second
}

void updateDHT11()
{
    // 設定 ESP8266 作為 Client 端
    WiFiClient client;
    if( !client.connect( HOST, PORT ) )
    {
        Serial.println( "connection failed" );
        return;
    }
    else
    {
        // 準備上傳到 ThingSpeak IoT Server 的資料
        // 已經預先設定好 ThingSpeak IoT Channel 的欄位
        // field1：溫度；field2：濕度
        String postStr = APIKEY + "&field1=" + String((int)temperature) + \
                                  "&field2=" + String((int)humidity) + "\r\n\r\n";

        client.print( "POST /update HTTP/1.1\n" );
        client.print( "Host: api.thingspeak.com\n" );
        client.print( "Connection: close\n" );
        client.print( "X-THINGSPEAKAPIKEY: "+APIKEY+"\n" );
        client.print( "Content-Type: application/x-www-form-urlencoded\n" );
        client.print( "Content-Length: " );
        client.print( postStr.length() );
        client.print( "\n\n" );
        client.print( postStr );

        client.stop();
    }
}