09-04-2012, 03:29 PM
MOTOR DRIVER L293D
IC L293 and Its avr interface v1.0.pdf (Size: 1.17 MB / Downloads: 115)
DC Motor
Whenever a robotics hobbyist talk about making a robot, the first thing comes to his mind is
making the robot move on the ground. And there are always two options in front of the
designer whether to use a DC motor or a stepper motor. When it comes to speed, weight, size,
cost... DC motors are always preferred over stepper motors. There are many things which you
can do with your DC motor when interfaced with a microcontroller. For example you can
control the speed of motor; you can control the direction of rotation.
DC Motor with Gear
The DC motors don’t have enough torque to drive a robot directly by connecting wheels in it.
Gears are used to increase the torque of dc motor on the expense of its speed.
Interface L293D with AVR
From Here I talk specifically with respect to our robot to control a motor using AVR we
need to control 3 pins as shown in above A, B and corresponding enable. Connections of motor
to ATmega8 are as shown below.
Motor speed control using PWM
If and only if you have gone though PWM tutorial proceed further. Suppose you want to
run motor by half of the its rating speed then send 50% duty cycle square wave at enable pin
effectively you will get 50% on tine but due to high frequency and inertia motor seems to run
continuously so code will be