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Motor

Table of Contents

  1. Hello World!
  2. Library
  3. Example

An interface for driving a standard DC motor with PWM and an H-Bridge

Hello World!

main.cpp

// Sweep speed from full-speed reverse (-1.0) to forwards (1.0)

#include "mbed.h"
#include "Motor.h"

Motor m(p23, p6, p5); // pwm, fwd, rev

int main() {
    for (float s= -1.0; s < 1.0 ; s += 0.01) {
       m.speed(s); 
       wait(0.02);
    }
}

Library

Import library
Motor - Motor Class Reference

Public Member Functions

Motor (PinName pwm, PinName fwd, PinName rev)
Create a motor control interface.
void speed (float speed)
Set the speed of the motor.

Example

This example show you how to wire up the L293D dual H bridge driver. Data sheet can be found at:

/media/uploads/chris/_scaled_l293d.png

some minor additions to the libary above, resulted in this libary. It has been tested on L298 motor drivers, but uses the same method of speed control.

in terms of use, the speed control is exactly the same. the coast function means the motor driver switches off, and does nothing.

the stop function dynamicaly brakes, which is supported on L298's but if dynamic braking develops more current than the motor drivers are rated for, things start to fail. read data sheet, and if in doubt, don't.

main.cpp

00071 // test code, this demonstrates working motor drivers. 
00072 // full reverse to full stop, dynamicaly brake and switch off.
      #include motordriver.h
00073 Motor A(p22, p6, p5, 1); // pwm, fwd, rev, can brake 
00074 Motor B(p21, p7, p8, 1); // pwm, fwd, rev, can brake
00075 int main() {
00076     for (float s= -1.0; s < 1.0 ; s += 0.01) {
00077        A.speed(s); 
00078        B.speed(s); 
00079        wait(0.02);
00080     }
00081     A.stop();
00082     B.stop();
00083     wait(1);
00084     A.coast();
00085     B.coast();
00086 }

data sheet for L298

conection diagrams to follow when Ive worked out how to upload them, poking paper at the ethernet port didn't work. it connects to a L293 in the same way.

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