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Your approach with the IR seems logical , though I'm not exactly sure what your task is. Do you basically want a soccer robot, a robot that pushes a ping pong ball into a goal, or a hitting robot, which hits the ball?Two other ways to detect the ball - a. use AVRcam or b. use a simple photoresistor / LED circuit to detect colors, im assuming the ping pong ball will be the only white thing there. The photoresistor would be the easiest, while the camera would be the coolest / most advanced.Also, a servo is a geared motor with a built in circuit that responds to a pulse given to it. The pulse given to it , controls to which angle the servo should turn to.Also, have you chosen on a microcontroller yet?
problem is that i can`t use light sources in the visible spectrum(E.G. LED).
Hey, another Ro-manian here. Here are my thoughts.Any ball is a sfere, so only a small spot that is perpendicular to the IR beam will reflect it back to the sensor. That's why round chair legs are hard to detect by the IR sensors. Ultrasonic sensors have a wider beam and longer range, they are much better at this.Now if you are mounting the sensor low, parallel with the table, (at the middle of the ball height) you can detect the balls easier. The Sharp sensor gives you a range and you need to calculate the distance to the object. But if you pan the sensor, you need verry small panning angles, or you will miss the balls that are further away from you.A cheaper way to do this is to use a IR LED modulated on a frequency like 38Hz and a sensor like TSOP4838. If you use PWM to flash the LED, modifying the pulse width will lower or increase the power of the LED, thus the distance of the object detection. Since the balls have a known color, you don't have to be concerned by the reflectivity of the object (a dark object will reflect less IR light than a white object). And you can get a LED with a wide beam...Good luck with your project!
PS: you`re romanian too?
so watcha thinking? could i measure the ball`s diamater using sharp ir?
omaryou need to start your own , new topic.this topic is about something else...And you don't need a robotics club to help you, you have this forum!Oh and about your question, you could have easily found an answer for that by searching the forum.Use a Sharp IR distance sensor.This is a usefull image that sumarizes the most common sensors:http://i156.photobucket.com/albums/t31/frank26080115/Screenshot.png