File content as of revision 2:887ff47839ed:

#include "mbed.h"
#include "DebounceIn.h"
#include "PinDetect.h"
#include "uLCD_4DGL.h"
#include "rtos.h"

Ticker flipper;
uLCD_4DGL uLCD(p13,p14,p28); // serial tx, serial rx, reset pin;
Serial xbee1(p9, p10);
DigitalOut rst1(p11);
DebounceIn forward(p16);
DebounceIn left(p17);
DebounceIn reverse(p18);
DebounceIn right(p24);
//forward   16
//left      17
//reverse   18
//right     19

DigitalOut led1(LED1); //four leds to display the command users send in
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
Mutex uLCD_lock; //mutex lock for the uLCD communication
volatile int voltage;
volatile int distance;


void read_battery() 
//read battery information back from the robot, need a mutex lock when 
//the information is written to the variable, otherwise "display_battery" 
//thread will try to access the the variable while it's changed
{

    xbee1.putc(15);
    //if (xbee1.readable()) {
        uLCD_lock.lock();
        voltage = xbee1.getc();
        uLCD_lock.unlock();
    //}
    //pc.printf("voltage: %i\n",voltage);
}

void read_distance() 
//read distance information back from the robot, need a mutex lock when 
//the information is written to the variable, otherwise "display_distance" 
//thread will try to access the the variable while it's changed
{
    xbee1.putc(16);
    //if (xbee1.readable()) {
        uLCD_lock.lock();
        distance = xbee1.getc();
        uLCD_lock.unlock();
    //}
    //pc.printf("distance: %i\n",distance);
}
void display_distance(void const *args) //update the distance sensor information in the LCD once every 0.3s
{
    while(1) {

        uLCD_lock.lock();
        uLCD.locate(1,5);
        float temp = float(1/(float(distance)/232*3.3))*30.53-2.64; //distance*232 scales reading back to a float between 0-1. Then a linear
                                                                    //approximation is used to convert float reading to cm reading
        uLCD.printf("%3.3fcm",temp);
        uLCD_lock.unlock();
        //pc.printf("%i\n",distance);
        Thread::wait(300);

    }
}

void display_battery(void const *args) //update the battery information in the LCD once every 0.3s
{
    while(1) {
        uLCD_lock.lock();
        uLCD.locate(1,3);
        uLCD.printf("%2.2fV",float(voltage)/232*3.3*2);
        //pc.printf("%i\n",voltage);
        uLCD_lock.unlock();
        Thread::wait(300);
    }
}

int main()
{
    forward.mode(PullUp);
    reverse.mode(PullUp);
    left.mode(PullUp);
    right.mode(PullUp);

    // reset the xbees (at least 200ns)
    rst1 = 0;
    wait_ms(100);
    rst1 = 1;
    wait_ms(100);
    uLCD.baudrate(3000000); //update the 
    uLCD.cls();
    wait(.01);
    uLCD.locate(1,2);
    uLCD.printf("Battery:\n");
    uLCD.locate(1,4);
    uLCD.printf("Distance:\n");
    Thread thread4(display_distance);
    Thread thread5(display_battery);

    while (1) {
        // loop to check if each pushbutton is pushed. If pushed, send a corresponding command to the robot
        if (forward==0) {
            led1 = 1;
            xbee1.putc(11);
        } else if (reverse==0) {
            led3 = 1;
            xbee1.putc(12);
        } else if (left==0) {
            led2 = 1;
            xbee1.putc(13);
        } else if (right == 0) {
            led4 = 1;
            xbee1.putc(14);
        } else {
            xbee1.putc(0);
            led1=led2=led3=led4=0; //reset all LED at the end of loop
        }
        read_distance(); //request distance information at the end of every loop
        read_battery(); //request battery information at the end of every loop
    }
}