Need help with controlling DC motors via USB and Arduino UNO

Solved
1

It seems to be the code is the problem,because I can switch on/off an LED via USB normally.But when I tried to control the DC motors, I have got no response.Here is the code that I used.


#define BLYNK_PRINT SwSerial


#include <SoftwareSerial.h>
SoftwareSerial SwSerial(10, 11); // RX, TX
    
#include <BlynkSimpleStream.h>

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "Token";

#define m11 5
#define m12 9
#define m21 10
#define m22 6

void forward()
{
  digitalWrite(m11, HIGH);
  digitalWrite(m12,LOW);
  digitalWrite(m21,HIGH);
  digitalWrite(m22,LOW);
}

void backward()
{
  digitalWrite(m11, LOW);
  digitalWrite(m12,HIGH);
  digitalWrite(m21,LOW);
  digitalWrite(m22,HIGH);
}

void right()
{
  digitalWrite(m11, HIGH);
  digitalWrite(m12,LOW);
  digitalWrite(m21,LOW);
  digitalWrite(m22,LOW);
}

void left()
{
  digitalWrite(m11, LOW);
  digitalWrite(m12,LOW);
  digitalWrite(m21,HIGH);
  digitalWrite(m22,LOW);
}

void Stop()
{
  digitalWrite(m11, LOW);
  digitalWrite(m12,LOW);
  digitalWrite(m21,LOW);
  digitalWrite(m22,LOW);
}

void setup()
{
  // Debug console
  SwSerial.begin(9600);

  // Blynk will work through Serial
  // Do not read or write this serial manually in your sketch
  Serial.begin(9600);
  Blynk.begin(Serial, auth);

  pinMode(m11, OUTPUT);
  pinMode(m12, OUTPUT);
  pinMode(m21, OUTPUT);
  pinMode(m22, OUTPUT);
  
}

BLYNK_WRITE(V1) {
  int x = param[0].asInt();
  int y = param[1].asInt();

  /* Do something with x and y
  SwSerial.print("X = ");
  SwSerial.print(x);
  SwSerial.print("; Y = ");
  SwSerial.println(y);*/

   if(y>220){
  forward();
   }
  else if(y<35){
  backward();
  }
  else if(x>220){
  right();
  }
  else if(x<35){
  left();
  }
  else{
  Stop();
  }
}

void loop()
{
  Blynk.run();
}
2

so to clarify: if you attach a led to any of those digital pins then they act correctly, but it you connect a DC motor it doesn’t? Have you connected the DC motor directly to a 5V output of the arduino (to test it) and did it run ?

3

NO!! don’t even test this!! you will kill your pin at the least, most probably the whole board.

I suspect the OP has a motor controller already connected to those respective pins, which are actually controlling two of 4 mosfets or something in an H-Bridge configuration. And on that note, setting the wrong two pins HIGH can create a dead short in the motor controller… so double/triple check.

@azrahakimi this is NOT a Blynk specific issue… but if you search this forum for key words like rover, car, robot, motor, etc… you will find other examples of how this can work.

4

I’ve figured it out. Seems that even if I connect a USB to my board (which did powered up my LED via a USB,so I assumed it powered my DC motors too) but it didn’t. I still have to put the batteries on and at the same time connect the USB to successfully control my DC motors.Silly mistakes :smiley: but thanks everyone for your comment.

5
6

Glad you figured it out.

I am closing this topic as it was not Blynk related in the first place.