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{ 2009 01 29 }

Control your motors with L293D

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

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

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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:

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.


The capacitors stabilize the current.

The same circuit on a breadboard:

Soldered on a pcb and ready to go:


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


// 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);
}

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

My 1st instructable  :)


Control your motors with L293D and Arduino – More DIY How To Projects

Posted by GUI on Thursday, January 29, 2009, at 5:34 am. Filed under L293D, Tutorials. Tagged , , , , , , , , , , , , , , , . Follow any responses to this post with its comments RSS feed. You can post a comment or trackback from your blog.

{ 17 } Comments

  1. Ricardo Vieira | February 5, 2009 at 6:38 pm | Permalink

    Hi!!
    Rely nice job…
    I’m having some difficulties. So you can post the back of the assembled circuit.
    Thanks a lot

  2. GUI | February 5, 2009 at 7:03 pm | Permalink

    Sure.. please wait until tomorrow ;)

  3. GUI | February 6, 2009 at 7:12 pm | Permalink

    Hi, there´s the photo, I hope it helps.
    Good luck

  4. Mário | February 6, 2009 at 8:23 pm | Permalink

    Aquele parafuso no transístor é para efeitos de dissipação de energia certo?

  5. GUI | February 6, 2009 at 10:37 pm | Permalink

    é sim :)

  6. Ricardo Vieira | February 25, 2009 at 2:22 pm | Permalink

    Utilizas-te apenas um capacitador no regulador de voltagem??
    Quais é que são as diferenças entre o ic L293d e o L293NE?

  7. GUI | February 25, 2009 at 4:29 pm | Permalink

    O regulador de voltagem tem 2 condensadores de 470uf cada, como podes ver na fotogradia está um de cada lado.
    Desconheço as diferenças entre a L293D e L293NE, consulta as datasheets.

  8. Ricardo Vieira | February 26, 2009 at 5:10 pm | Permalink

    desculpa 1 condensador de 0,1uf

  9. GUI | February 26, 2009 at 10:52 pm | Permalink

    ele está lá, mas está por baixo do parafuso por isso não se vê

  10. Ricardo Vieira | February 27, 2009 at 6:09 pm | Permalink

    eu sei que ele está lá vesse, mas no outro guia para o qual tu tens o link no inicio da pagina está o esquema com 2 condensadores de 0.1uf e tu só utilizas um. Não é preciso o segundo? Era isso que eu queria saber

  11. GUI | February 27, 2009 at 11:55 pm | Permalink

    estão lá os dois, e um deles está de baixo do parafuso por isso não se vê :)

  12. Reuben | October 15, 2009 at 5:35 pm | Permalink

    I saw the link to the letsmakerobot’s web site about power regulators, but could you show a breadboard or schematic picture of what you used as a power regulator? I’m having a tricky time picturing it from your complete PCB pictures. Thank you.

  13. GUI | October 15, 2009 at 11:44 pm | Permalink

    Hi!
    Take a look into these tutorial: http://itp.nyu.edu/physcomp/Tutorials/ArduinoBreadboard
    Check the first five photos, the power regulator circuit is very well explained ;)

  14. HL | April 10, 2010 at 8:12 pm | Permalink

    Hi there. Thanks for the wonderful instructable. I do have a question though.

    I understand from your instructable that L293D is controlled by MCU inputs.

    Is it necessary L293D and the MCU to share the same power source?? for example common ground.

    This is urgent. hope to hear from you guys soon.

    thanks.

  15. Primos | July 1, 2010 at 8:27 pm | Permalink

    Hi.. I would just like to ask, what is the purpose of the capacitors? Thanks for your answers in advance!

  16. Primos | July 1, 2010 at 8:30 pm | Permalink

    Ups… Sry… I didn’t see..
    ____

    The capacitors stabilize the current.

  17. Nuno | August 21, 2010 at 8:01 pm | Permalink

    sr. Guilherme eu sou muito novo nestas andanças e queria ajuda .
    no compilador do Arduino o codigo “void turn_right() {, da-me erro o que se passa?
    não vou matar mais a cabeça, por isso pesso ajuda .
    OBRIGADO

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