There are many interesting sensors on the market that can be harnessed with an Arduino for our benefit, and one fascinating example is the Avago ADNS-9800 Optical Laser Sensor. This is used to detect motion, for example used in a trackball to determine the rotation of the ball - but can be used for other purposes as well. For example it could be mounted on the bottom of a robotic vehicle to determine speed, or for creating a new form of user-interface.
Either way you'll need to know how - and this has been documented by Instructables user "Gigi10012". They've shown how to use the sensor to display distance travelled with an LCD module, and included the required sketch and circuitry. A quick demonstration of this is shown in the following video:
It's great to see these tutorials about parts that at first seem somewhat unapproachable - so visit the Instructable to get moving. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you're interested in adding an LCD to your Arduino-based projects - save time and move forward with the Freetronics LCD & Keypad shield which contains a bright 16x2 character LCD and five buttons that can be read from only one analogue input pin: