Use 2 Ultrasonic sensors at the same time

I was wondering if anyone can help me.
I want to measure the width of a tunnel with 2 ultrasonic sensors attached to each side of an RC car.
I wonder if anyone know how to combine the readings of both sensors.
Here is the code I’m triying to use

#include <LiquidCrystal.h>
#define TRIG 9, 10
#define ECHO 8, 11 
LiquidCrystal lcd(2, 3, 4, 5, 6, 7);
long Tiempo;
float Distancia;

void setup() {
  lcd.begin(16, 2);
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);

}

void loop() {
 digitalWrite(TRIG, HIGH);
 delayMicroseconds(120);
 digitalWrite(TRIG, LOW);
 Tiempo = (pulseIn(ECHO, HIGH)/2);
 Distancia = float(Tiempo * 0.0343);
 lcd.setCursor(0,0);
 lcd.print("Distancia: ");
 lcd.print(Distancia);
 delay(120); 
 }

And sample image of my Car
Image

Take readings of both sensors (separately); add up the distance; add the distance between the sensors themselves; and you have the width of the tunnel.

I see code for only one sensor, and the way you do the #define it probably will not even compile.

#define TRIG 9, 10
#define ECHO 8, 11

must be individial..

#define TRIG1 9
#define TRIG2 10
#define ECHO1 8
#define ECHO2 11

Read sensors.. first one.. then the other

wvmarle:
Take readings of both sensors (separately); add up the distance; add the distance between the sensors themselves; and you have the width of the tunnel.

I see code for only one sensor, and the way you do the #define it probably will not even compile.

Then the code would be something like this:

#include <LiquidCrystal.h>
#define TRIG 9
#define ECHO 8
#define TRIG2 10
#define ECHO2 11
LiquidCrystal lcd(2, 3, 4, 5, 6, 7);
long Tiempo;
float Distancia;
float Distancia2;
float DistanciaT; 
void setup() {
 lcd.begin(16, 2);
 pinMode(TRIG, OUTPUT);
 pinMode(ECHO, INPUT);
 pinMode(TRIG2, OUTPUT);
 pinMode(ECHO2, INPUT);
}
void loop() {
 digitalWrite(TRIG, HIGH);
 delayMicroseconds(10);
 digitalWrite(TRIG, LOW);
 Tiempo = (pulseIn(ECHO, HIGH)/2);
 Distancia = float(Tiempo * 0.0343);
 digitalWrite(TRIG2, HIGH);
 delayMicroseconds(10);
 digitalWrite(TRIG2, LOW);
 Tiempo = (pulseIn(ECHO2, HIGH)/2);
 Distancia2 = float(Tiempo * 0.0343);
 DistanciaT = Distancia+Distancia2;
 lcd.setCursor(0,0);
 lcd.print("Distancia: ");
 lcd.print(DistanciaT);
 delay(10);
}

It compiles this time
Distancia=distance of sensor 1
Distancia2=distance of sensor 2
DistanciaT=the result of the sum of Distancia and Distancia2