Unable to make motors move together

Projects General Guidance
1

Hi,

I am trying to make an obstacle avoiding bot using arduino. I have used Li ion 7.4 V battery to power the L298Ndriver and the driver in turn is powering the arduino.

However the motors are not spinning the wheels together or are working haphazardly. I am unable to get them to work according to the code.

I am attaching my code and picture of my connections below:
'
#include <Servo.h>
int p = 0;
int r = 13;
Servo motor;
float dist_front;
float dist_left;
float dist_right;
const int trig = 9;
const int echo = 10;
//motor driver
int speedl = 5;
int pin1 = 4;
int pin2 = 7;
int pin3 = 1;
int pin4 = 2;
int speedr = 3;

void setup() {

Serial.begin(9600);
motor.attach(6);
motor.write(180);
pinMode(6, OUTPUT);
pinMode(13, OUTPUT);
digitalWrite(13, HIGH);
//motor driver
pinMode(speedl, OUTPUT);
pinMode(speedr, OUTPUT);
pinMode(pin1, OUTPUT);
pinMode(pin2, OUTPUT);
pinMode(pin3, OUTPUT);
pinMode(pin4, OUTPUT);
}

void loop() {
motor.write(90);
dist_front = measuring_distance(trig, echo);
while (dist_front > 15) {
go_forward();
dist_front = measuring_distance(trig, echo);
}
stop();
dist_front = measuring_distance(trig, echo);
delay(2000);
motor.write(180);
dist_left = measuring_distance(trig, echo);
delay(2000);
motor.write(0);
dist_right = measuring_distance(trig, echo);
delay(2000);
motor.write(90);
go_backward();
delay(1000);
if (dist_right > dist_left) {
//turn right
turn_right();
} else {
//turn left
turn_left();
}
}

float measuring_distance(int trigpin, int echopin) {
float distance;
float duration;
digitalWrite(trigpin, LOW);
delayMicroseconds(2);
digitalWrite(trigpin, HIGH);
delayMicroseconds(10);
digitalWrite(trigpin, LOW);
duration = pulseIn(echopin, HIGH);
distance = (0.034 * duration) / 2;
return (distance);
}
void turn_left() {
digitalWrite(pin1, HIGH);
digitalWrite(pin2, LOW);
analogWrite(speedl, 100);
digitalWrite(pin3, HIGH);
digitalWrite(pin4, LOW);
analogWrite(speedr, 100);
delay(662);
analogWrite(speedl, 0);
analogWrite(speedr, 0);
}
void turn_right() {
digitalWrite(pin4, HIGH);
digitalWrite(pin3, LOW);
analogWrite(speedr, 100);
digitalWrite(pin1, LOW);
digitalWrite(pin2, HIGH);
analogWrite(speedl, 100);
delay(662);
analogWrite(speedl, 0);
analogWrite(speedr, 0);
delay(1000);
}
void go_forward() {
digitalWrite(pin1, LOW);
digitalWrite(pin2, HIGH);
analogWrite(speedl, 100);
digitalWrite(pin3, HIGH);
digitalWrite(pin4, LOW);
analogWrite(speedr, 100);
}
void stop() {
analogWrite(speedl, 0);
analogWrite(speedr, 0);
}
void go_backward() {
digitalWrite(pin1, HIGH);
digitalWrite(pin2, LOW);
analogWrite(speedl, 100);
digitalWrite(pin4, HIGH);
digitalWrite(pin3, LOW);
analogWrite(speedr, 100);
}
'
Please help with this

2

Please read the advice in the topic "How to get the best from this forum".
Post formatted code, not text.
No picture visible.
Post schematics.

3

A schematic of your actual project as it exists, not a cut-n-paste of a page from elsewhere. Not a fritzing diagram either.

4

Welcome chaithanyay! Probably the best place for the L298N is the trash bin, you will lose about 3 volts through it that will be burnt up as heat. This heat energy will be subtracted from the motor and still supplied by your battery. This will have a big negative impact on torque and speed. Look for a MOSFET output bridge large enough to drive your motor.

There are two ways to keep motors in sync, connect there shafts together or use speed feedback. Voltage and current will not be accurate over time as the motors are different and will wear at different rates.

5

What model Arduino are you using? On the UNO, Nano, Mega, and others Pin 1 is part of the Serial interface so you can't use it to control a motor while also using Serial.

6

I am using the arduino uno. Ok So, ill avoid this pin and try again

7

johnwasser, it really worked. Didnt know about pin 1. Thanks a lot for pointing it out.

8

Excellent! Have fun.