Let's Make Robots!

Control your motors with L293D

UPDATE

***********************************************************************************************
update 26/4/09
***********************************************************************************************

My 1st instructable  :)

http://www.instructables.com/id/HiTec-Servo-Hack/

***********************************************************************************************
***********************************************************************************************

After long research and trial and error,  I´ve came up to a new walkthrough regarding this nice chip, the L293D.

Each project is one project and each one has its own unique power configurations, so you must be aware of the best battery choice and how to distribute voltage through your robot.

I strongly advice you to read the following articles:

Picking Batteries for your Robot
Once you’ve decided on batteries, how do you regulate the voltage

************************************************

L293D gives you the possibility to control two motors in both directions - datasheet

************************************************

The L293D Circuit:

Basic Implementation:

This is the most basic implementation of the chip.

As you can see, a 5V Voltage Regulator is between the battery and pins 1, 9, 16.

Pin 8 gets power before the VReg, if your motor needs for example 6V you should put 6V directly in this pin, all the other pins should not get more than 5V.

This will work with no problem at all, but if you want to do the right implementation take a look at the next example:

3235657956_b3be2b4f2f.jpg?v=0

3262168342_ae12307934.jpg?v=1240780647

This is the correct Implementation (with the capacitors), and note that pin 8 is feeded by unregulated voltage. This means that if your motors need more than 5V, you should power this pin with that amount of voltage, and the rest of the circuit with 5V.

3235658022_f78495fddd.jpg?v=0
The capacitors stabilize the current.

The same circuit on a breadboard:
3252941552_2f4919475f.jpg?v=1240780044

Soldered on a pcb and ready to go:
3234563157_780312a389.jpg?v=0
3451483356_2fdf26be19.jpg?v=0

3257970545_12de4f710e.jpg?v=0

This is the back of the circuit, click for high resolution photo.

***********************************************************************************************
CODE
***********************************************************************************************

// Use this code to test your motor with the Arduino board:

// if you need PWM, just use the PWM outputs on the Arduino
// and instead of digitalWrite, you should use the analogWrite command

// —————————————————————————  Motors
int motor_left[] = {2, 3};
int motor_right[] = {7, 8};

// ————————————————————————— Setup
void setup() {
Serial.begin(9600);

// Setup motors
int i;
for(i = 0; i < 2; i++){
pinMode(motor_left[i], OUTPUT);
pinMode(motor_right[i], OUTPUT);
}

}

// ————————————————————————— Loop
void loop() {

drive_forward();
delay(1000);
motor_stop();
Serial.println(”1″);

drive_backward();
delay(1000);
motor_stop();
Serial.println(”2″);

turn_left();
delay(1000);
motor_stop();
Serial.println(”3″);

turn_right();
delay(1000);
motor_stop();
Serial.println(”4″);

motor_stop();
delay(1000);
motor_stop();
Serial.println(”5″);
}

// ————————————————————————— Drive

void motor_stop(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], LOW);

digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], LOW);
delay(25);
}

void drive_forward(){
digitalWrite(motor_left[0], HIGH);
digitalWrite(motor_left[1], LOW);

digitalWrite(motor_right[0], HIGH);
digitalWrite(motor_right[1], LOW);
}

void drive_backward(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], HIGH);

digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], HIGH);
}

void turn_left(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], HIGH);

digitalWrite(motor_right[0], HIGH);
digitalWrite(motor_right[1], LOW);
}

void turn_right(){
digitalWrite(motor_left[0], HIGH);
digitalWrite(motor_left[1], LOW);

digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], HIGH);
}

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
would it be possible to have a second power source generating 9V but limit the power input to the chip to 4.5V using a voltage regulator ? i am asking because i need to use a second power source at 9V but the L293D gets realy hot at just 4.5.
Yep, having a second source will work, with the grounds tied together. I think Vcc1 is meant to be a 5 volt supply, while Vcc2 is to run the motors, which is suppose to be anything from 5 to 36 volts if I remember the data sheet corrrectly.

any information about L298N H-Bridge

anything else than its data sheet...

I only found the L293NE, does it changes anything?

 

The datasheet doesn't provide much details on the L293NE, only on the L293D and the L293...

Is L293NE, L293D and L293 the same thing?

Check Fritsl's Start Here and theres a link to the Chips he used

Fristl used a L293D, I'll be using a L293NE, wich is not the same IC, but I need to know if I need some diodes.

The l293ne is like the standard l293, so yeah, you'd need to use diodes. The one you wouldn't with is the l293dne.

The ne model appears to just use a plastic encasing.

 

thanks.

Which diodes should I use ?
You should do this same tutorial  but with a Picaxe 28x1 Board because it could be useful in conjuction with the YDM tutorial