IOT Robot with NodeMCU and Arduino using Blynk.

Introduction:

Controlling robots wirelessly is great fun. There are many methods available through which you can control your robot wirelessly.

They are:

1.  RF remote controller
2.  Bluetooth signal
3.  IR signal
4.  Wifi or IOT etc...

Here I have made a project of robot controlled over IOT using blynk app,arduino and nodemcu.

Things needed

• Arduino
• Nodemcu(Esp8266)
• 2 DC motors and Motor driver
• LCD display(may or may not added)
• Batteries or any other power source
• Blynk Application 
• Jumper wires etc.

Step 1: Building the Body of Robot

I Build the robot with Sun-board and card board gluing them with super glue. I used old mobile batteries as source and stick them to body. here are some pictures of my build.

Step 2: Connection of different elements

• Connect two dc motors to the motor driver. for more about motor drivers follow this:https://www.ganeshgadgets.co.in/2017/09/line-follower-part-2-motor-driver.html
• Connect arduino to the motor driver. use enable of motor driver with PWM inputs of arduino.
• Power up nodemcu with arduino from 5v pin. Here the idea is when arduino receives digital output from nodemcu at its input pins it would do certain actions.
• 5 outputs from nodemcu(D0-D4) is fed to 5 pins of arduino(A0 toA5 -here digital pins are used so pin 14 to pin 19).
• Example when D0 of nodemcu is high, Arduino receives signal and command noter driver to go forward. 

Code example:
if ( digitalRead(a0) == HIGH ) //forward//
 {
  lcd.setCursor(0, 1);
  lcd.print("FORWARD ");
  digitalWrite(af, HIGH);
  digitalWrite(ar, LOW);
  digitalWrite(bf, HIGH);
  digitalWrite(br, LOW);
 }

• To view commands you can also add a LCD-16x2 module to the robot which is very helpful for troubleshooting. To interface 16x2 module: https://www.ganeshgadgets.co.in/2018/01/16x2-lcd-interface-with-arduino.html    

 Step 3: Programming Nodemcu and Arduino

• First of all you need to load blynk "standalone" code into the Nodemcu.for this you should follow my previous post: https://www.ganeshgadgets.co.in/2018/09/iot-switch-using-nodemcu-and-blynk-app.html. 
• Open Blynk app create 5 buttons preferably push-button type and assign them from D0 to D4.
• Open Arduino and write following codes.

Code:

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 10, 11, 12, 13); //16x2 lcd interface

int en = 3;//a-right motor  b-Left motor //

int af = 6;int ar = 7;

int bf = 5;int br = 4;

int a0=14 , a1=15 , a2= 16 ,a3= 17, a4= 18;//from nodemcu D0 to D4//

void setup() {

lcd.begin(16, 2); 

 pinMode(en,OUTPUT);

 pinMode(ar,OUTPUT);pinMode(af,OUTPUT);

 pinMode(bf,OUTPUT);pinMode(br,OUTPUT);

 pinMode(a0,INPUT); pinMode(a1,INPUT); pinMode(a2,INPUT);

 pinMode(a3,INPUT); pinMode(a4,INPUT);

 digitalWrite(en,HIGH);

// loading();

}

void loop() {

  

  if ( digitalRead(a0) == HIGH ) //forward//

 {

  lcd.setCursor(0, 1);

  lcd.print("FORWARD "); 

  digitalWrite(af, HIGH);

  digitalWrite(ar, LOW);

  digitalWrite(bf, HIGH);

  digitalWrite(br, LOW);

 }

   if (digitalRead(a1) == HIGH) //backward//

    {

  lcd.setCursor(0, 1);

  lcd.print("BACKWARD"); 

  digitalWrite(af, LOW);

  digitalWrite(ar,HIGH);

  digitalWrite(bf, LOW);

  digitalWrite(br, HIGH);

    }

  if (digitalRead(a2) == HIGH)  //RIGHT

    {

  lcd.setCursor(0, 1);

  lcd.print("RIGHT     ");     

  digitalWrite(af, LOW);

  digitalWrite(ar,HIGH);

  digitalWrite(bf, HIGH);

  digitalWrite(br,LOW);

      } 

  if (digitalRead(a3) == HIGH)//LEFT

    {

  lcd.setCursor(0, 1);

  lcd.print("LEFT      ");        

  digitalWrite(af, HIGH);

  digitalWrite(ar,LOW);

  digitalWrite(bf, LOW);

  digitalWrite(br, HIGH);

    }

  if (digitalRead(a4) == HIGH)//STOP

    {

  lcd.setCursor(0, 1);

  lcd.print("STOP      ");        

  digitalWrite(af, HIGH);

  digitalWrite(ar, HIGH);

  digitalWrite(bf, HIGH);

  digitalWrite(br, HIGH);

    }  

  else

  {

  lcd.setCursor(0, 1);

  lcd.print("        ");          

  digitalWrite(af, HIGH);

  digitalWrite(ar, HIGH);

  digitalWrite(bf, HIGH);

  digitalWrite(br, HIGH);

   }

} 

Conclusion:

You can easily build this. you can add lights to the robot and also other features using nodemcu. here is working video of the robot.

https://youtu.be/UsY_pJP5PVc

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