Wifi Controlled Robot Car Using Nodemcu and Blynk

• 1 x Nodemcu
• 1 x Lm298 motor driver
• 2 x Bo motors
• 3 x wheels
• jumper wires
• 9v battery
• 5v powerbank/battery

Getting to Know Your L298N Dual H-Bridge Motor Controller Module .An H-Bridge is a circuit that can drive a current in either polarity and be controlled by Pulse Width Modulation (PWM). What is Pulse Width Modulation? Pulse Width Modulation is a means in controlling the duration of an electronic pulse. Motors will last much longer and be more reliable if controlled through PWM.

• Specifications:
• Double H bridge Driver Chip: L298N
• Logical voltage: 5V
• Drive voltage: 5V-35V
• Logical current: 0-36mA
• Drive current: 2A (MAX single bridge)
• Max power: 25W
• Note: Built-in 5v power supply, when the driving voltage is 7v-35v. But i recommend you not to power up your microcontroller with on-board 5v power supply.

1:connect the bo motor to the motor driver as shown in the image above

2: connect the motor driver to nodemcu as given below:

• GPIO2(D4)- IN3
• GPIO15(D8)-IN1
• GPIO0(D3)-IN4
• GPIO13(D7)-IN2
• GPIO14(D5)-Enb-A
• GPIO12(D6)-Enb-B

3:Supply Connections :

• +12v - Positive terminal of the battery to be connected.
• GND - Ground terminal of the battery to be connected.
• +5v - +5v input (unnecessary if your power source is less than +7v to +9v, if the power source is greater than +9v to +35v then it can act as a 5v out)
• 4:Input Connections :
• (Motor A) ENA - Enables PWM signal for Motor A
• IN1 -Enable Motor A
• IN2 - Enable Motor A
• (Motor B) ENB - Enables PWM signal for Motor B
• IN3: Enable Motor B
• IN4: Enable Motor B

Note : Make sure you have all of your grounds connected together. (NodeMCU, Power Source, and Motor Driver)The PWM Pins are unnecessary if you do not want to control PWM features.

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1. Blynk setup
2. arduino setup

Blynk setup:

• Open the blynk app
• click on new project
• select the Nodemcu board and wifi connection
• click on the plus symbol present on the right corner of app and select joystick and the slider
• now click on the joystick select the virtual pin v1 because i have written the code for v1 and slide the button from split to merge
• set the value range from 0-1023 because it helps in easy control of robot for larger values
• now select the slider , select the virtual pin v2,and set values from 0 - 1023.

Arduino IDE setup:

• Click on the Icon to open the Arduino window
• Open the File and click on the Preferences
• Adding ESP8266 Board Manager
• In the Additional Boards Manager enter below URL. http://arduino.esp8266.com/stable/package_esp8266... As highlighted in the figure and enter OK.
• Selecting Board

Now open the tools in that select Board: “Arduino/Genuino Uno” and click on the Boards Manager as shown in the figure

• ESP8266 Board Package

The Boards Manager window opens, scroll the window page to bottom till you see the module with the name ESP8266. Once we get it, select that module and select version and click on the Install button. When it is installed it shows Installed in the module as shown in the figure and then close the window.

• Selecting ESP8266 Arduino Board

To run the esp8266 with Arduino we have to select the Board: “Arduino/Genuino Uno” and then change it to NodeMCU 1.0 (ESP-12E Module) or other esp8266 modules depending on what you have .This can be done by scrolling down, as shown in the figure

• Connecting ESP8266 to the PC

Now Let’s connect the ESP8266 module to your computer through USB cable as shown in the figure. When module is connected to the USB, COM port is detected eg: here COM5 is shown in the figure.

#include

#include

/* define L298N or L293D motor control pins */

int leftMotorForward = 2; /* GPIO2(D4) -> IN3 */

int rightMotorForward = 15; /* GPIO15(D8) -> IN1 */

int leftMotorBackward = 0; /* GPIO0(D3) -> IN4 */

int rightMotorBackward = 13; /* GPIO13(D7) -> IN2 */

int z;

/* define L298N or L293D enable pins */

int rightMotorENB = 14; /* GPIO14(D5) -> Motor-A Enable */

int leftMotorENB = 12; /* GPIO12(D6) -> Motor-B Enable *

/ You should get Auth Token in the Blynk App. // Go to the Project Settings (nut icon).

// Use your own WiFi settings

char auth[] = "**********";

char ssid[] = "type your network name here ";

char pass[] = "type your network password here";

// neutral zone settings for x and y

// joystick must move outside these boundary numbers to activate the motors

// makes it a little easier to control the wifi car

int minRange = 312;

int maxRange = 712;

// analog speeds from 0 (lowest) - 1023 (highest)

// 3 speeds used -- 0 (noSpeed), 350 (minSpeed), 850 (maxSpeed).

// use whatever speeds you want...too fast made it a pain in the ass to control

int minSpeed = 450;

int maxSpeed = 1023;

int noSpeed = 0;

void moveControl(int x, int y) {

// movement logic // move forward

// y je vetsi jak maxrange a současně x je vetsi jak minRange a současne mensi jak max range

if(y >= maxRange && x >= minRange && x <= maxRange) {

analogWrite(leftMotorENB,z);

analogWrite(rightMotorENB,z);

digitalWrite(leftMotorForward,HIGH);

digitalWrite(rightMotorForward,HIGH);

digitalWrite(leftMotorBackward,LOW);

digitalWrite(rightMotorBackward,LOW); } //MOVE FORWARD RIGHT

else if(x <= minRange && y >= maxRange ) {

digitalWrite(leftMotorENB,maxSpeed);

digitalWrite(rightMotorENB,minSpeed);

digitalWrite(leftMotorForward,HIGH);

digitalWrite(rightMotorForward,HIGH);

digitalWrite(rightMotorBackward,LOW);

digitalWrite(leftMotorBackward,LOW); } // move right

else if(x >= maxRange && y >= minRange && y<=maxRange)

{ analogWrite(leftMotorENB,z);

analogWrite(rightMotorENB,z);

digitalWrite(leftMotorForward,HIGH);

digitalWrite(rightMotorForward,LOW);

digitalWrite(rightMotorBackward,HIGH);

digitalWrite(leftMotorBackward,LOW);

}

// move forward LEFT

else if(x <= minRange && y >= maxRange ) {

digitalWrite(leftMotorENB,minSpeed);

digitalWrite(rightMotorENB,maxSpeed);

digitalWrite(leftMotorForward,HIGH);

digitalWrite(rightMotorForward,HIGH);

digitalWrite(rightMotorBackward,LOW);

digitalWrite(leftMotorBackward,LOW); }

// moveleft else if(x <= minRange && y >= minRange && y <= maxRange) {

analogWrite(leftMotorENB,z);

analogWrite(rightMotorENB,z);

digitalWrite(leftMotorForward,LOW);

digitalWrite(rightMotorForward,HIGH);

digitalWrite(rightMotorBackward,LOW);

digitalWrite(leftMotorBackward,HIGH); }

// neutral zone

else if(y < maxRange && y > minRange && x < maxRange && x > minRange)

{ digitalWrite(leftMotorENB,LOW);

digitalWrite(rightMotorENB,LOW);

digitalWrite(leftMotorForward,LOW);

digitalWrite(leftMotorBackward,LOW);

digitalWrite(rightMotorForward,LOW);

digitalWrite(rightMotorBackward,LOW); }

// move back

else if(y <= minRange && x >= minRange && x <= maxRange) {

analogWrite(leftMotorENB,z);

analogWrite(rightMotorENB,z);

digitalWrite(leftMotorBackward,HIGH);

digitalWrite(rightMotorBackward,HIGH);

digitalWrite(leftMotorForward,LOW);

digitalWrite(rightMotorForward,LOW); }

// move back and right

else if(y <= minRange && x <= minRange) {

digitalWrite(leftMotorENB,maxSpeed);

digitalWrite(rightMotorENB,minSpeed);

digitalWrite(leftMotorForward,LOW);

digitalWrite(rightMotorForward,LOW);

digitalWrite(rightMotorBackward,HIGH);

digitalWrite(leftMotorBackward,HIGH); }

// move back and left

else if(y <= minRange && x >= maxRange) {

digitalWrite(leftMotorENB,minSpeed);

digitalWrite(rightMotorENB,maxSpeed);

digitalWrite(leftMotorForward,LOW);

digitalWrite(rightMotorForward,LOW);

digitalWrite(rightMotorBackward,HIGH);

digitalWrite(leftMotorBackward,HIGH); } }

void setup() {

// initial settings for motors off and direction forward

pinMode(leftMotorForward, OUTPUT);

pinMode(rightMotorForward, OUTPUT);

pinMode(leftMotorBackward, OUTPUT);

pinMode(rightMotorBackward, OUTPUT);

/* initialize motor enable pins as output */

pinMode(leftMotorENB, OUTPUT);

pinMode(rightMotorENB, OUTPUT);

Blynk.begin(auth, ssid, pass); }

void loop() {

Blynk.run(); }

BLYNK_WRITE(V1)

{ int x = param[0].asInt();

int y = param[1].asInt();

moveControl(x,y); }

BLYNK_WRITE(V2)

{ z = param[0].asInt(); }