main.cpp

00001 /*
00002     ちょうおんぱせんさHC-SR04をしよう
00003     LCDにきょりをひょうじ
00004     30cmいかのきょりならばＬＥＤがひかる
00005 */
00006 #include "mbed.h"
00007 #include "TextLCD.h"
00008 
00009 TextLCD lcd(D12, D11, D10, D9, D8, D7, TextLCD::LCD20x2); // rs, e, d4-d7 
00010 DigitalOut trigger(D15);
00011 DigitalOut myled(LED1);
00012 DigitalIn  echo(D14);
00013 int distance = 0;
00014 int correction = 0;
00015 Timer sonar;
00016  
00017 int main()
00018 {
00019     sonar.reset();
00020     while(1) {
00021 // trigger sonar to send a ping
00022         trigger = 1;
00023         sonar.reset();
00024         wait_us(10.0);
00025         trigger = 0;
00026 //wait for echo high
00027         while (echo==0) {};
00028 //echo high, so start timer
00029         sonar.start();
00030 //wait for echo low
00031         while (echo==1) {};
00032 //stop timer and read value
00033         sonar.stop();
00034 //subtract software overhead timer delay and scale to cm
00035         distance = (sonar.read_us()-correction)/58.0;
00036         if(distance <= 30){
00037             myled = 1;
00038         } else {
00039             myled = 0;
00040         }
00041         lcd.printf("%d cm \n\r",distance);
00042 //wait so that any echo(s) return before sending another ping
00043         wait(0.2);
00044     }
00045 }