Control Robot Car 4WD Mecanum Wheel use app Android, install app here:

https://play.google.com/store/apps/details?id=com.bluino.esp8266wifirobotcar

/******************* WiFi Robot Remote Control Mode ********************/
#include <WiFi.h>
#include <ArduinoOTA.h>
#include <ESPAsyncWebServer.h>


// connections for drive Motors
int PWM_A = 12;
int PWM_B = 13;
int DIR_A = 14;
int DIR_B = 15;

const int buzPin = 5;      // set digital pin D5 as buzzer pin (use active buzzer)
const int ledPin = 4;      // set digital pin D8 as LED pin (use super bright LED)
const int wifiLedPin = 2;  // set digital pin D0 as indication, the LED turn on if NodeMCU connected to WiFi as STA mode


String command;          // String to store app command state.
int SPEED = 1023;        // 330 - 1023.
int speed_Coeff = 1023;

AsyncWebServer server(80);


void notFound(AsyncWebServerRequest *request) {
  request->send(404, "text/plain", "Not found");
}


unsigned long previousMillis = 0;

String sta_ssid = "your_ssid_name";      // set Wifi networks you want to connect to
String sta_password = "your_ssid_password";  // set password for Wifi networks



void setup(){
  Serial.begin(115200);    // set up Serial library at 115200 bps
  Serial.println();
  Serial.println("*ESP32 WiFi Robot Remote Control Mode*");
  Serial.println("--------------------------------------");
 
  pinMode(buzPin, OUTPUT);      // sets the buzzer pin as an Output
  pinMode(ledPin, OUTPUT);      // sets the LED pin as an Output
  pinMode(wifiLedPin, OUTPUT);  // sets the Wifi LED pin as an Output
  digitalWrite(buzPin, LOW);
  digitalWrite(ledPin, LOW);
  digitalWrite(wifiLedPin, HIGH);
    
  // Set all the motor control pins to outputs
  pinMode(PWM_A, OUTPUT);
  pinMode(PWM_B, OUTPUT);
  pinMode(DIR_A, OUTPUT);
  pinMode(DIR_B, OUTPUT);
  
  // Turn off motors - Initial state
  digitalWrite(DIR_A, LOW);
  digitalWrite(DIR_B, LOW);

  ledcSetup(0, 1000 , 8);
  ledcAttachPin(PWM_A, 0);
  ledcSetup(1, 1000 , 8);
  ledcAttachPin(PWM_B, 1);


  // set ESP32 Wifi hostname based on chip mac address
  char chip_id[15];
  snprintf(chip_id, 15, "%04X", (uint16_t)(ESP.getEfuseMac()>>32));
  String hostname = "esp32Car-" + String(chip_id);


  Serial.println();
  Serial.println("Hostname: "+hostname);


  // first, set NodeMCU as STA mode to connect with a Wifi network
  WiFi.mode(WIFI_STA);
  WiFi.begin(sta_ssid.c_str(), sta_password.c_str());
  Serial.println("");
  Serial.print("Connecting to: ");
  Serial.println(sta_ssid);
  Serial.print("Password: ");
  Serial.println(sta_password);


  // try to connect with Wifi network about 10 seconds
  unsigned long currentMillis = millis();
  previousMillis = currentMillis;
  while (WiFi.status() != WL_CONNECTED && currentMillis - previousMillis <= 5000) {
    delay(500);
    Serial.print(".");
    currentMillis = millis();
  }


  // if failed to connect with Wifi network set NodeMCU as AP mode
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("");
    Serial.println("*WiFi-STA-Mode*");
    Serial.print("IP: ");
    Serial.println(WiFi.localIP());
    digitalWrite(wifiLedPin, HIGH);    // Wifi LED on when connected to Wifi as STA mode
    delay(3000);
  } else {
    WiFi.mode(WIFI_AP);
    WiFi.softAP(hostname.c_str());
    IPAddress myIP = WiFi.softAPIP();
    Serial.println("");
    Serial.println("WiFi failed connected to " + sta_ssid);
    Serial.println("");
    Serial.println("*WiFi-AP-Mode*");
    Serial.print("AP IP address: ");
    Serial.println(myIP);
    digitalWrite(wifiLedPin, LOW);   // Wifi LED off when status as AP mode
    delay(3000);
  }
 


  // Send a GET request to <ESP_IP>/?fader=<inputValue>
    server.on("/", HTTP_GET, [] (AsyncWebServerRequest *request) {
    String inputValue;
    String inputMessage;


    // Get value for Forward/Backward
    if (request->hasParam("State")) {
      inputValue = request->getParam("State")->value();
      
      if (inputValue.equals("F")) Forward();          // check string then call a function or set a value
      else if (inputValue.equals("B")) Backward();
      else if (inputValue.equals("R")) TurnRight();
      else if (inputValue.equals("L")) TurnLeft();
      else if (inputValue.equals("G")) ForwardLeft();
      else if (inputValue.equals("H")) BackwardLeft();
      else if (inputValue.equals("I")) ForwardRight();
      else if (inputValue.equals("J")) BackwardRight();
      else if (inputValue.equals("S")) Stop();
      else if (inputValue.equals("V")) BeepHorn();
      else if (inputValue.equals("W")) TurnLightOn();
      else if (inputValue.equals("w")) TurnLightOff();
      else if (inputValue.equals("0")) SPEED = 330;
      else if (inputValue.equals("1")) SPEED = 400;
      else if (inputValue.equals("2")) SPEED = 470;
      else if (inputValue.equals("3")) SPEED = 540;
      else if (inputValue.equals("4")) SPEED = 610;
      else if (inputValue.equals("5")) SPEED = 680;
      else if (inputValue.equals("6")) SPEED = 750;
      else if (inputValue.equals("7")) SPEED = 820;
      else if (inputValue.equals("8")) SPEED = 890;
      else if (inputValue.equals("9")) SPEED = 960;
      else if (inputValue.equals("q")) SPEED = 1023;
      else inputValue = "No message sent";
    }
     
    Serial.println(inputValue);
    inputValue="";
    request->send(200, "text/text", "");
  });


  server.onNotFound (notFound);    // when a client requests an unknown URI (i.e. something other than "/"), call function "handleNotFound"
  server.begin();  


  
  ArduinoOTA.begin();                       // enable to receive update/uploade firmware via Wifi OTA
}



void loop() {
    ArduinoOTA.handle();          // listen for update OTA request from clients
}


// function to move forward
void Forward(){ 
  digitalWrite(DIR_A, HIGH);
  digitalWrite(DIR_B, HIGH);

  ledcWrite(0, SPEED);
  ledcWrite(1, SPEED);
}

// function to move backward
void Backward(){
  digitalWrite(DIR_A, LOW);
  digitalWrite(DIR_B, LOW);
  ledcWrite(0, SPEED);
  ledcWrite(1, SPEED);
}

// function to turn right
void TurnRight(){
  digitalWrite(DIR_A, HIGH);
  digitalWrite(DIR_B, LOW);
  ledcWrite(0, SPEED);
  ledcWrite(1, SPEED);
}

// function to turn left
void TurnLeft(){
  digitalWrite(DIR_A, LOW);
  digitalWrite(DIR_B, HIGH);
  ledcWrite(0, SPEED);
  ledcWrite(1, SPEED);
}

// function to move forward left
void ForwardLeft(){
  digitalWrite(DIR_A, HIGH);
  digitalWrite(DIR_B, HIGH);
  ledcWrite(1, SPEED);
  ledcWrite(0, SPEED/speed_Coeff);
}

// function to move backward left
void BackwardLeft(){
  digitalWrite(DIR_A, LOW);
  digitalWrite(DIR_B, LOW);
  ledcWrite(1, SPEED);
  ledcWrite(0, SPEED/speed_Coeff);
}

// function to move forward right
void ForwardRight(){
  digitalWrite(DIR_A, HIGH);
  digitalWrite(DIR_B, HIGH);
  ledcWrite(1, SPEED/speed_Coeff);
  ledcWrite(0, SPEED);
}

// function to move backward left
void BackwardRight(){ 
  digitalWrite(DIR_A, LOW);
  digitalWrite(DIR_B, LOW);
  ledcWrite(1, SPEED/speed_Coeff);
  ledcWrite(0, SPEED);
}

// function to stop motors
void Stop(){  
  digitalWrite(DIR_A, LOW);
  digitalWrite(DIR_B, LOW);
  ledcWrite(0, 0);
  ledcWrite(1, 0);
}

// function to beep a buzzer
void BeepHorn(){
  digitalWrite(buzPin, HIGH);
  delay(150);
  digitalWrite(buzPin, LOW);
  delay(80);
  digitalWrite(buzPin, HIGH);
  delay(150);
  digitalWrite(buzPin, LOW);
  delay(80);
}

// function to turn on LED
void TurnLightOn(){
  digitalWrite(ledPin, HIGH);
}

// function to turn off LED
void TurnLightOff(){
  digitalWrite(ledPin, LOW);
}