Are you a beginner and want make something out of interest? Well, this is one project that would help you grasp the basics of electronics. Just follow the instructions given and learn how to make a speed detection device using arduino that can be used with Mac, Windows and Android.
An Arduino Duemilanove with ATMega328 having a couple of photoresistors is used here. In order to direct the laser on to the photo-resistors, two laser pointers are utilized. A light sensor senses the variations in light and the Arduino keeps track of these values. Changes that take place when the laser beam is disrupted, is also monitored by the Arduino. In the case of disruption of both laser beams, the difference in time at a point when both sensors trip is calculated. This value is transferred to a Flash based client, which by means of a USB port and a serial port proxy is linked to the Arduino.
When the required values are passed to the Adobe Air based client, it reads through the trip time for each sensor. Once this is done, the distance between the sensors is calculated and this information is used to calculate the actual speed.
That does it. Your circuit is done and ready to calculate speed. This project may be just a simple one. But the concept can be really helpful for RC car gears tweaking and setup purposes. Tweaking both, maximum speed and acceleration can be done.
Click here to visit the project page.