#include <Wire.h>
#include "Adafruit_LEDBackpack.h"
#include "Adafruit_GFX.h"
Adafruit_7segment matrix = Adafruit_7segment();
int triggerPin=5;
int echoPin=7;
long duration=0;
float cm=0;
void setup() {
  matrix.begin(0x70);
  pinMode(triggerPin,OUTPUT);
  pinMode(echoPin,INPUT);
}
  void loop(){
  digitalWrite(triggerPin,LOW);
  delayMicroseconds(5);
  digitalWrite(triggerPin,HIGH);
  delayMicroseconds(5);
  digitalWrite(triggerPin,LOW);
  delayMicroseconds(5);
  duration=pulseIn(echoPin,HIGH);
  cm = duration /29.0 /2.0;
  matrix.print(cm);
  matrix.writeDisplay();
  matrix.print(cm);
  matrix.writeDisplay();
  delay(300);
}