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In this program,
BUILT-IN LED on NodeMCU Board is controlled using TalkBack Application from https://thingspeak.com server (cloud).
Internal ESP8266 WiFi Module is used to connect to the Internet and send data to https://thingspeak.com server
The output is shown using LED & Serial Monitor on PC.
Note:
TalkBack application is the feature in which,we can store some commands on thinkspeak server and then we can call those commands using API.
When we trigger particular API, we receive some command as a response and then we can control the output device (Eg. LED) as per received response from the cloud.
Apart from that, we can also add, delete and Change the commands using APIs
Recommended Internet of Things (IOT) Courses:
- Udemy: Complete Guide to Build IOT Things from Scratch to Market
- LinkedIn: IoT Foundations: Fundamentals
- edX: Introduction to the Internet of Things (IoT)
- edureka: IoT Certification Training on Azure
- Coursera: An Introduction to Programming the Internet of Things (IOT) Specialization
- Eduonix: Internet Of Things (IOT) Bundle
Requirements:
1. NodeMCU (ESP8266) Board2. Micro-USB Cable
3. Arduino IDE (Installed on PC)
4. Active Internet Connection
Physical Connections:
Steps:
- Sign up at https://thingspeak.com
- Apps > TalkBalk > New TalkBack > Update "Name" > Click on "Add a new Command"
update position=1, command string=LED_ON > Click on "Add a new Command"
update position=2, command string=LED_OFF" > Save TalkBalk - Copy following things and replace those in the below program:
a. API_Key
b. TalkBack_ID
c. Command_ID (For LED_ON)
d. Command_ID (For LED_OFF) - Make all the Connections to NodeMCU board mentioned Above.
- Change Following 6 fields in below written program.
a. ssid_name (Name of you WiFi)
b. password (Passord of your WiFi)
c. API_Key
d. TalkBack_ID
e. Command_ID
FORMAT:
https://api.thingspeak.com/talkbacks/<TalkBack_ID>/commands/<COMMAND_ID>?api_key=<API_Key>
Replace <TalkBack_ID>, <Command_ID> and <API_Key> by actual values
(you got from step 3.a, 3.b, 3.c or 3.d respectively) - Upload Program to Arduino Mega Board
- Open Arduino Serial Monitor on PC (Set Baud Rate to 115200 and set "Both NL & CR")
Program Outcome:
BUILT-IN LED on NodeMCU Board should blink with specific interval.Observe the connection to the thinkspeak server and received msgs using Serial monitor.
For Better understanding you can watch demonstration video given below:
Downloads:
Download link is given in the Description of the YouTube video shown below.
Demonstration:
Program:
// Import Libraries #include <Arduino.h> #include <ESP8266WiFi.h> #include <ESP8266WiFiMulti.h> #include <ESP8266HTTPClient.h> #define USE_SERIAL Serial // Set Macro ESP8266WiFiMulti WiFiMulti; // Create Object of ESP8266WiFiMulti const int relay = 16; // Output device Connected at pin 16 void setup() { pinMode(LED_BUILTIN, OUTPUT); // set LED_BUILTIN as OUTPUT pinMode(relay, OUTPUT); // set LED_BUILTIN as OUTPUT digitalWrite(relay, HIGH); // Set relay as High USE_SERIAL.begin(115200); // NodeMCU to PC communication Baud Rate=115200 // USE_SERIAL.setDebugOutput(true); USE_SERIAL.println(); USE_SERIAL.println(); USE_SERIAL.println(); for(uint8_t t = 4; t > 0; t--) { USE_SERIAL.printf("[SETUP] WAIT %d...\n", t); // display msg on PC USE_SERIAL.flush(); // wait for a serial string to be finished sending delay(1000); // wait for 1 sec } WiFiMulti.addAP("SuiteUp", "welcome@10"); // connect to WiFi } void loop() { // wait for WiFi connection if((WiFiMulti.run() == WL_CONNECTED)) { // If WiFi is connected HTTPClient http; // Create Object of HTTPClient USE_SERIAL.print("[HTTP] begin...\n"); // Display msg on PC /*********************** START: LED_ON TALKBAK ***************************/ // Replace <TalkBack_ID>, <Command_ID> and <API_Key> by actual values here http.begin("http://184.106.153.149/talkbacks/20941/commands/10327032?api_key=CLMIBI9XMK35YJWQ"); //HTTP //LED_ON Get a TalkBack Command USE_SERIAL.print("[HTTP] GET...\n"); // Display msg on PC int httpCode = http.GET(); // start connection and send HTTP header // httpCode will be negative on error if(httpCode > 0) { // HTTP header has been send and Server response header has been handled USE_SERIAL.printf("[HTTP] GET... code: %d\n", httpCode); // file found at server if(httpCode == HTTP_CODE_OK){ // check in ESP8266HTTPClient.h . //HTTP_CODE_OK=200 String payload = http.getString(); // payload = Response from server USE_SERIAL.println(payload); // Display payload on PC if(payload=="LED_OFF"){ // If Responcse from server = "LED_OFF" digitalWrite(LED_BUILTIN, HIGH); // LED OFF (Common Anode) digitalWrite(relay, HIGH); // Relay High } if(payload=="LED_ON"){ // If Responcse from server = "LED_ON" digitalWrite(LED_BUILTIN, LOW); // LED ON (Common Anode) digitalWrite(relay, LOW); // Relay Low } } } else{ USE_SERIAL.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str()); // Display Error msg to PC } /*********************** END: LED_ON TALKBAK ***************************/ delay(10000); // Wait for 10 Sec /*********************** START: LED_OFF TALKBAK ***************************/ // Replace <TalkBack_ID>, <Command_ID> and <API_Key> by actual values here http.begin("http://184.106.153.149/talkbacks/20941/commands/10327039?api_key=CLMIBI9XMK35YJWQ"); //HTTP //LED_OFF Get a TalkBack Command USE_SERIAL.print("[HTTP] GET...\n"); // Display msg on PC httpCode = http.GET(); // start connection and send HTTP header // httpCode will be negative on error if(httpCode > 0) { // HTTP header has been send and Server response header has been handled USE_SERIAL.printf("[HTTP] GET... code: %d\n", httpCode); // file found at server if(httpCode == HTTP_CODE_OK){ // check in ESP8266HTTPClient.h . //HTTP_CODE_OK=200 String payload = http.getString(); // payload = Response from server USE_SERIAL.println(payload); // Display payload on PC if(payload=="LED_OFF"){ // If Responcse from server = "LED_OFF" digitalWrite(LED_BUILTIN, HIGH); // LED OFF (Common Anode) digitalWrite(relay, HIGH); // Relay High } if(payload=="LED_ON"){ // If Responcse from server = "LED_ON" digitalWrite(LED_BUILTIN, LOW); // LED ON (Common Anode) digitalWrite(relay, LOW); // Relay Low } } } else{ USE_SERIAL.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str()); // Display Error msg to PC } /*********************** END: LED_OFF TALKBAK ***************************/ http.end(); // Close Connection } delay(10000); // Wait for 10 Sec }
Click here to see more codes for Raspberry Pi 3 and similar Family.
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Click here to see more codes for NodeMCU ESP8266 and similar Family.
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Click here to see more codes for Arduino Mega (ATMega 2560) and similar Family.
Click here to see more codes for NodeMCU ESP8266 and similar Family.
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Click here to see more codes for Arduino Mega (ATMega 2560) and similar Family.
Feel free to ask doubts in the comment section. I will try my best to solve it.
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This is the simplest way to encourage me to keep doing such work.
Thanks and Regards,
-Akshay P. Daga