This is the most important part of an autonoums bots , without this der cant be an autonoums bot build. There are different types of sensors used varying with work to be done with the bot.
This sensors are used to measure the intensity of light.Mostly commonly used under this are LDR(light dependent resistors) , TSOP1738,IRLED pair,Photodiode,Phototransistor.
They can be used as obstacle avoidance, in line follower to differentiate btw black and white.
Its a resistor whose value decreases with intensity of light, more the intensity of light lesser will be the resistence and vice versa , which means when this sensor is in dark place there is less resistence.Now the question will be how can we use it as sensor for our bot we use LEDs(red mostly) in combination with LDR,.
I L PUT UP THE CKT OF IT IN MY OTHER POST.
http://www.technologystudent.com/elec1/ldr1.htm (FOR MORE HELP)
Its basically a pair of diodes one is the reciever and the other a transmitter(dark blue in colour) both modulated to same frequency .The transmitter works in forward bias condition and the reciever in reverse bias condition.It has two terminals the longer one is the + ve one n other -ve .
How does it work:
The transmitter sends a light at partiular freq though u cannot c it , the receiver detects it when it bounces back from some obstacle.
THE CKT WULD BE PUT IN OTHER POST.
This sensor is mostly used by students for various competiotns.
This is mostly used when we want our sensors to work in more ambient lite , sunlite i can say for.
This thing is found in TV remote controller.
THESE SENSORS TAT I HAVE TOLD ARE ONLY LIGHT SENSORS,
Apart from these the sensors tat are there are
accelometers :Used to detect motion, vibration, ngle with respect to gravity
Colour sensors:Used to detect diff colours
Sonar Sensors:Determines obstacle from a distance
Bump switch:touches the object and gives the signal
I will discuss about these sensors in more detail in later posts .