With this you can measure distances from point A to point B faster just by pointing. It's pretty accurate and cheap to make. Connect everything as shown below.
The GREEN LED will light up if the distance is more than 100 cm and the RED LED will light up if the distance is less than 100 cm from the subject. To view the distance measurements, simply open up the Arduino IDE. Click "TOOLS" and select Serial Monitor. As long as your Arduino is connected to the PC via USB, you will receive measurements.