Author Topic: l293 motor driver  (Read 9348 times)

0 Members and 1 Guest are viewing this topic.

Offline TrumpkinTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,177
  • Helpful? 5
l293 motor driver
« on: June 14, 2008, 03:59:47 PM »
I should be able to use this diagram for controlling motors with the $50 robot, and other microcontrollers, right?
Robots are awesome!

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,660
  • Helpful? 169
    • Society of Robots
Re: l293 motor driver
« Reply #1 on: June 18, 2008, 09:34:24 AM »
So you decided to ditch the servos, eh? :P

Yeap, that diagram will work.

Offline Webbot

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 2,150
  • Helpful? 110
Re: l293 motor driver
« Reply #2 on: June 18, 2008, 01:28:12 PM »
You need to add 4 diodes as well to prevent the motor frying the chip!! If your current requirements are low (say 500mA) then use the L293D instead - this has got the diodes built in.  Check the datasheets and you will see the L293 can provide higher current but you will need to add the diodes yourself - in which case look at the L293D datasheet to see how the diodes are connected.
Webbot Home: http://webbot.org.uk/
WebbotLib online docs: http://webbot.org.uk/WebbotLibDocs
If your in the neighbourhood: http://www.hovinghamspa.co.uk

Offline TrumpkinTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,177
  • Helpful? 5
Re: l293 motor driver
« Reply #3 on: June 18, 2008, 02:57:21 PM »
Okay! thanks 
Quote
So you decided to ditch the servos, eh?

No, I haven't, it just seems like I always have dc motors laying around that I would like to use. Here is a new schematic I found http://www.freewebs.com/isuru-c/motor_driver.htm but I'm not sure what pins go to the microcontroller.
« Last Edit: June 18, 2008, 03:14:39 PM by Trumpkin »
Robots are awesome!

Offline TrumpkinTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,177
  • Helpful? 5
Re: l293 motor driver
« Reply #4 on: June 20, 2008, 03:24:10 PM »
It seems like there should be 3 pins per motor that go to the microcontroller but I only see 2 pins per motor.
Robots are awesome!

Offline Webbot

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 2,150
  • Helpful? 110
Re: l293 motor driver
« Reply #5 on: June 20, 2008, 06:07:18 PM »
Not quite sure what you mean. The circuit diagram you attached showed 2 connections per motor - where does the '3 connections' come from?
Webbot Home: http://webbot.org.uk/
WebbotLib online docs: http://webbot.org.uk/WebbotLibDocs
If your in the neighbourhood: http://www.hovinghamspa.co.uk

Offline izua

  • Supreme Robot
  • *****
  • Posts: 682
  • Helpful? 0
Re: l293 motor driver
« Reply #6 on: June 20, 2008, 06:27:36 PM »
there are three pins on input, each pair of push-pull drivers has an enable (pwm) signal :P
Check out my homepage for in depth tutorials on microcontrollers and electronics.

Offline TrumpkinTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,177
  • Helpful? 5
Re: l293 motor driver
« Reply #7 on: June 21, 2008, 07:47:34 AM »
Quote
Not quite sure what you mean. The circuit diagram you attached showed 2 connections per motor - where does the '3 connections' come from?
It seems like there should be negative, positive, and signal wires that go to the microcontroller for each motor, like a servo, but I only see 2.
« Last Edit: June 21, 2008, 07:54:56 AM by Trumpkin »
Robots are awesome!

Offline Webbot

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 2,150
  • Helpful? 110
Re: l293 motor driver
« Reply #8 on: June 22, 2008, 07:44:00 AM »
Quote
Here is a new schematic I found http://www.freewebs.com/isuru-c/motor_driver.htm but I'm not sure what pins go to the microcontroller.


The diagram should show that pins 1 and 9 are input 'enable' pins. These give you the third input from your microcontroller and can be pulsed (PWM) to change the speed
Webbot Home: http://webbot.org.uk/
WebbotLib online docs: http://webbot.org.uk/WebbotLibDocs
If your in the neighbourhood: http://www.hovinghamspa.co.uk

Offline ixarka

  • Beginner
  • *
  • Posts: 4
  • Helpful? 0
Re: l293 motor driver
« Reply #9 on: June 22, 2008, 10:21:15 AM »
Quote
Here is a new schematic I found http://www.freewebs.com/isuru-c/motor_driver.htm but I'm not sure what pins go to the microcontroller.


The diagram should show that pins 1 and 9 are input 'enable' pins. These give you the third input from your microcontroller and can be pulsed (PWM) to change the speed


Alternatively, if you want to save an output pin from your microcontroller, you can wire the enable to +5V and use PWM on either of the other two pins to control speed. To turn the motor off, set both pins either high or low.

Offline izua

  • Supreme Robot
  • *****
  • Posts: 682
  • Helpful? 0
Re: l293 motor driver
« Reply #10 on: June 22, 2008, 10:43:00 AM »
enable = pwm
:P
Check out my homepage for in depth tutorials on microcontrollers and electronics.

 


Get Your Ad Here