File content as of revision 0:5d1796a0f9ce:

#include "mbed.h"

Serial pc(USBTX,USBRX);

DigitalInOut pingPin1(p18);
DigitalInOut pingPin2(p19);

Timer tmr1, tmr2,tmr;
Timeout timeouter;
int flag=0;

long microsecondsToCentimeters(long microseconds);

void reset()
{
    flag = 0;
    tmr.reset();
}

int main()
{
    pc.baud(115200);
    while (1) {
        long duration1, duration2,USSDistance1, USSDistance2, cm1, cm2, time;

        pingPin1.output();
        pingPin1 = 0;
        wait_us(2);
        pingPin1 = 1;
        wait_us(5);
        pingPin1 = 0;

        pingPin1.input(); // pulseIn
        tmr1.reset();

        while (!pingPin1); // wait for high
        tmr1.start();
        while (pingPin1); // wait for low
        tmr1.stop();
        duration1 = tmr1.read_us();
        USSDistance1 = duration1;// * 0.0170;

        cm1 = microsecondsToCentimeters(USSDistance1);

        if(15<cm1&&cm1<40) {
            if(flag==0) {
                flag=1;
                tmr.reset();
                tmr.start();
                timeouter.attach(&reset, 5);
            }
            if(flag==1) {
                timeouter.detach();
                timeouter.attach(&reset, 5);
            }
            time=tmr.read_ms();
            printf("1: %d  %d[ms]\n", cm1,time);
        }

        wait_ms(10);
        

        pingPin2.output();
        pingPin2 = 0;
        wait_us(2);
        pingPin2 = 1;
        wait_us(5);
        pingPin2 = 0;

        pingPin2.input(); // pulseIn
        tmr2.reset();

        while (!pingPin2); // wait for high
        tmr2.start();
        while (pingPin2); // wait for low
        tmr2.stop();

        duration2 = tmr2.read_us();
        USSDistance2 = duration2;// * 0.0170;

        cm2 = microsecondsToCentimeters(USSDistance2);
        if(15<cm2&&cm2<40) {
            time=tmr.read_ms();
            printf("                 2: %d %d[ms]\n",cm2,time);
        }
        wait_ms(10);
        }
}

long microsecondsToInches(long microseconds)
{
    return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds)
{
    return microseconds / 29 / 2;
}