Find a Sensor.

A few days ago, Dr.Zul ask me to find a sensor to put to his little robot. He wants a sensor that can sense object in front of the robot. Then, I make some research and I found a few types of sensor which is proximity sensor, infrared, photoelectric distance sensor and etc.

A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. The sensor often emits an electromagnetic field or beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive or photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor always requires a metal target. The maximum distance that this sensor can detect is defined ''nominal range''. Some sensors have adjustments of the nominal range or means to report a graduated detection distance. I think, proximity sensor is not suitable for the mini robot, cause the sensor is big and the function of the sensor itself not suitable for my dear robot. (mine?)..

Then, I read a little bit about the photoelectric distance sensor, a photoelectric sensor, or photoeye, is a device used to detect the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are used extensively in industrial manufacturing. There are three different functional types: opposed (a.k.a. through beam), retroreflective, and proximity-sensing (a.k.a. diffused). Thru on my reading, I think that the function between proximity and photoelectric sensor are similar. So, the photoelectric sensor also doesn't suitable for the robot. 

I was wondering how about car's sensor? Does it suitable for the robot? Then, I'll update later on car's sensor. Still searching for the info. :)