t6ZwHGqV

1/*
2Problem Statement: Receive data from thingSpeak Channel  
3                   WiFi Credentials are not hardcoded, They can be updated in real time using Tzapu WiFiManager Library
4Developed by: Rahul Shrivastava
5*********************************
6*/
7
8#include <Arduino.h>//
9#include <ESP8266WiFi.h>
10#include <ESP8266HTTPClient.h>
11#include <DNSServer.h>
12#include <WiFiManager.h> //https://github.com/tzapu/WiFiManager
13
14String readAPIkey = "702L9HBEV9F88HHV";// Read API Key of ThingSpeak channel
15String channel_ID = "1024134";
16String field_N = "2";
17String result_N = "1";
18        //"http://api.thingspeak.com/channels/1024134/fields/2.json?api_key=702L9HBEV9F88HHV&results=1"
19
20void setup() {
21    Serial.begin(115200);
22    Serial.flush();
23    pinMode(D0, OUTPUT);
24    wificonnect();         
25}
26
27void loop() {
28
29        float temperature = GETreceive();
30        if (temperature>33)
31        {
32          digitalWrite(D0, LOW);  
33        }
34        else
35        {
36           digitalWrite(D0, HIGH);   
37        }
38}
39
40void wificonnect()
41  {
42    WiFiManager wifiManager;
43    wifiManager.autoConnect("RS_Receiver_Node");
44    Serial.println("connected to RS_receiver_Node:)");
45  }
46
47float GETreceive()
48{
49        HTTPClient http;    
50 
51        Serial.print("[HTTP] begin...\n");
52       
53        //"http://api.thingspeak.com/channels/963373/fields/1.json?api_key=28WYJLR74BJ9ZKAT&results=1"
54        String url =  "http://api.thingspeak.com/channels/";
55               url += channel_ID; // 
56               url += "/fields/";
57               url += field_N;
58               url += ".json?api_key=";
59               url += readAPIkey;
60               url += "&results=";
61               url += result_N;
62               Serial.println(url);
63        http.begin(url); //HTTP
64 
65        Serial.print("[HTTP] GET...\n");
66       
67        // start connection and send HTTP header
68        int httpCode = http.GET();
69 
70        // httpCode will be negative on error
71       
72        if(httpCode > 0) {
73            // HTTP header has been send and Server response header has been handled
74            Serial.printf("[HTTP] GET... code: %d\n", httpCode);
75 
76                if(httpCode == HTTP_CODE_OK) {
77                String payload = http.getString();
78                Serial.println(payload);
79                
80                int begin_b = payload.indexOf("\"entry_id");
81                String field_data_string = payload.substring(begin_b+25,begin_b+30);
82                float field_data = field_data_string.toFloat();
83                Serial.println(field_data_string);
84                Serial.println(field_data);
85                return(field_data);
86             }
87         }
88        else
89        {
90            Serial.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str());
91        }
92 
93        http.end();
94     
95    delay(16000);   
96}