File content as of revision 1:0d55a4bf2269:

#include "mbed.h"
#include "MODSERIAL.h'

DigitalOut Direcion_M1(D4);
DigitalOut Speed_M1(D5);
//DigitalOut Speed_M2(D6);                  
//DigitalOut Direction_M2(D7);

DigitalIn Switch_1(D8);
int counter=1;

MODSERIAL pc(USBTX, USBRX);                   

int main(){
    pc.baud(115200);
    pc.printf("RESET \n");
    
    digitalWrite(Direction_M1, 1);   //The arm will initially get longer  
    analogWrite(Speed_M1, 0);        //The motor is initially turned off
    
    while (true){
        if (switch_1 == 0){
            switch (counter){
                case 1:
                    counter++;
                    digitalWrite(Direction_M1, 1);   //The arm will get longer  
                    analogWrite(Speed_M1, 255);      //The motor is turned on
                    pc.printf("The arm will now get longer");
                    wait(0.5f);
                    break;
                case 2:
                    counter++;
                    digitalWrite(Direction_M1, 1);   //The arm will get longer  
                    analogWrite(Speed_M1, 0);        //The motor is turned off
                    pc.printf("The arm will now stop");
                    wait(0.5f);
                    break;
                case 3:
                    counter++;
                    digitalWrite(Direction_M1, 0);   //The arm will get shorter  
                    analogWrite(Speed_M1, 255);      //The motor is turned off
                    pc.printf("The arm will now get shorter");
                    wait(0.5f);
                    break;
                case 4:
                    counter++;
                    digitalWrite(Direction_M1, 0);   //The arm will get shorter 
                    analogWrite(Speed_M1, 0);        //The motor is turned off
                    pc.printf("The arm will now stop");
                    wait(0.5f);
                    break;
                case 5:
                    counter = 1;
                    break;
            }     
        } 
    }
}