make a 4 wheels robot turn

Hi everyone,
I'm here with a new question. Can I make a 4 wheels robot turn using the Motor Shield? I don't know the DC motors well, so I was looking for a guide, but I didn't find any.

This is the sketch I used, and it worked. All the four motors go in the same direction.

#include <AFMotor.h>

AF_DCMotor motor1(1);
AF_DCMotor motor2(2);
AF_DCMotor motor3(3);
AF_DCMotor motor4(4);

void setup() {

void loop() {

How can I make the robot turn?
Thank you all.;;;

Try changing those to all 4 FORWARD or all 4 BACKWARD. It may be that in order for the robot to go straight forward the motors on one side rotate one way and the motors on the opposite side must rotate the other way.

I'm sorry, nothing happens...

Bummer. What should happen? If you change the code back, does something happen? Maybe share the code that makes nothing happen?

You have been on the forum long enough to know that we need details to be able to help. Vague questions and statement can only yield vague answers.

What motors and motor drivers are you using? Power supply? Wiring diagram?

Power supply: 9v battery

Motor driver:

I am using DC motor.

The code I used is the same as before, but I tried setting all the DC motors to "FORWARD" so the wheels on a side go back and the wheels on the other side go forward.

It worked stopping those wheels.

It worked stopping those wheels.

So they were moving and stopped when the FORWARD command was executed?

And do the motors move when you change the code back to the code in the original post?

What are the motor specifications? Rated voltage? Running current? Stall current?

If the battery is a rectangular 9V :smoke alarm" battery, I would not expect it to power motors for very long. Is the battery dead?

L293 motor drivers are ancient technology. They drop 2 to 4 volts and dissipate that as heat. So your motors get 2 - 4 volts less than the supply voltage. Pololu has some nice modern drivers that are much more efficient.

The two wheels on a side received the FORWARD command, and the two wheels on the other side didn't get any input. The motors work between 6 and 9 volts... I do not know more, I bought them here. Anyway, now the problem has been fixed!

Anyway, now the problem has been fixed!

You care to share the fix? Might help someone else.