Simplest wifi car using ESP8266 Motorshield

I found very simple way to make a wifi car. You actually need 4 things: NodeMcu esp8266 Amica, esp motorshield, chassis and your smartphone. So that's it, let's get started!

ESP motorshield

There's not so much information on the Internet about this board. First of all this shield for ESP-12E Dev Kit and NodeMcu boards and not for all, because width between pins is 25mm and that's not enough for some boards like LoLin. In my project I used NodeMcu Amica.

This shield board is driven by the special excent large power full-bridge chip L293DD from the famous Stmicroelectronics company, which can directly drive 2-channels DC motors or one-channel stepper motor. The driven current can be arrived at 1.2A.

Motor power: can be up to 36V.

ESP power: can be up to 9V. Because it goes straight to the esp without any voltage regulators.

Also these pins have common ground, you can connect voltage supply to one pin and use shortcut for other(if voltage less than 9V).

Board uses 4 pins to control motors. PWMA, PWMB- speed of motors. DA, DB-direction of motors(0-straight;1-reverse).

Here pinout for NodeMcu Amica.

• PWMA-GPIO5.
• PWMB-GPIO4.
• DA-GPIO0.
• DB-GPIO2.

Circuit

That's how I connected all this stuff. For power supply I use 2 Samsung INR18650-30Q connected in series. About motors, I connect 2 motors in parallel to each motor outputs- PWMA(Left side), PWMB(Right side).Make sure that motors will rotate in one direction when you connect it.

Blynk application

In Blynk application we need only joystick.

Set joystick to merge mode for work with Virtual pins. Values for both axis from (-1) to 1.

ESP code

Esp code is default Blynk project with handling data from joystick at Virtual pin- 1.

#define BLYNK_PRINT Serial 
#include <ESP8266WiFi.h> 
#include <BlynkSimpleEsp8266.h> 
// You should get Auth Token in the Blynk App. 
// Go to the Project Settings (nut icon). 
char auth[] = "YourAuthToken"; 
// Your WiFi credentials. 
// Set password to "" for open networks. 
char ssid[] = "YourNetworkName"; 
char pass[] = "YourPassword"; 
int PWMA=5;//Right side 
int PWMB=4;//Left side 
int DA=0;//Right reverse 
int DB=2;//Left reverse 
void setup(){ 
 // Debug console 
 Serial.begin(9600); 
 Blynk.begin(auth, ssid, pass); 
 pinMode(PWMA, OUTPUT); 
 pinMode(PWMB, OUTPUT); 
 pinMode(DA, OUTPUT); 
 pinMode(DB, OUTPUT); 
} 
void loop(){ 
Blynk.run(); 
  
} 
// Handling Joystick data 
BLYNK_WRITE(V1){ 
int x = param[0].asInt(); 
int y = param[1].asInt();  
if(x==-1 && y==-1){             //Backward and Left     
     digitalWrite(PWMA, LOW); 
     digitalWrite(DA, LOW); 
     
     digitalWrite(PWMB, HIGH); 
     digitalWrite(DB, HIGH); 
}else if(x==-1 && y==0){        //Left Turn 
     digitalWrite(PWMA, 450); 
     digitalWrite(DA, HIGH); 
    
     digitalWrite(PWMB, 450); 
     digitalWrite(DB, LOW); 
}else if(x==-1 && y==1){        //Forward and Left     
     digitalWrite(PWMA, LOW); 
     digitalWrite(DA, LOW); 
    
     digitalWrite(PWMB, HIGH); 
     digitalWrite(DB, LOW); 
}else if(x==0 && y==-1){        //Backward     
     digitalWrite(PWMA, HIGH); 
     digitalWrite(DA, HIGH); 
     
     digitalWrite(PWMB, HIGH); 
     digitalWrite(DB, HIGH);
}else if(x==0 && y==0){        //Stay 
     digitalWrite(PWMA, LOW); 
     digitalWrite(DA, LOW); 
     
     digitalWrite(PWMB, LOW); 
     digitalWrite(DB, LOW); 
}else if(x==0 && y==1){        //Forward 
     digitalWrite(PWMA, HIGH); 
     digitalWrite(DA, LOW); 
    
     digitalWrite(PWMB, HIGH); 
     digitalWrite(DB, LOW); 
}else if(x==1 && y==-1){        //Backward and Right     
     digitalWrite(PWMA, HIGH); 
     digitalWrite(DA, HIGH); 
     
     digitalWrite(PWMB, LOW); 
     digitalWrite(DB, LOW); 
}else if(x==1 && y==0){        //Right turn 
     digitalWrite(PWMA, 450); 
     digitalWrite(DA, LOW); 
     
     digitalWrite(PWMB, 450); 
     digitalWrite(DB, HIGH); 
}else if(x==1 && y==1){        //Forward and Right 
     digitalWrite(PWMA, HIGH); 
     digitalWrite(DA, LOW); 
     
     digitalWrite(PWMB, LOW); 
     digitalWrite(DB, LOW);
 } 
}

Nothing complicated, data handling is done by if-else if...

Test

All is done! Here video with tests.

I'm currently freelancer. For hiring, you can contact me at about.prototype@gmail.com