F15: Quadcopter by Thomas

Abstract

The goal of this project is try to implement the basic function of a drone, fly and controlling the direction by remote control.

Design & Implementation

PWM

The four motor on the done is controlled by the PWM (Pulse Width Modulation). The SJSUone board already gave us a good library to use, so we just have to set the frequency and pin at the beginning of the code.

The example of using the library.

#define PWM_FREQ 500
#include "lpc_pwm.hpp"
#include "uart0.hpp"
#include "stdio.h"

void motor_test()
{

    PWM servo1(PWM::pwm1, PWM_FREQ);
    PWM servo2(PWM::pwm2, PWM_FREQ);
    PWM servo3(PWM::pwm3, PWM_FREQ);
    PWM servo4(PWM::pwm4, PWM_FREQ);


    Uart0& terminal = Uart0::getInstance();
    terminal.init(38400);

    float p;
    int num;

    while(1){

        printf("NO=");
        scanf("%d",&num);
        printf("pwm percent=");
        scanf("%f", &p);
			
        switch(num){

            case 1:
                servo1.set(p);
                break;

            case 2:
                servo2.set(p);
                break;

            case 3:
                servo3.set(p);
                break;

            case 4:
                servo4.set(p);
                break;

            default:
                return;
        }
    }
}

Here is the diagram shows the output of the PWM. PWM_FREQ variable from the previous sample code can control the period and p variable can control the duration.

The picture of the SJdrone