Sensors for line follower

Both will work, but LDR's have a slow response compared to IR Sensors, hence go for IR Sensors

Yes I agree with shobhitkukreti that you can use both of them and the LDRs have a slower response. Moreover the IR sensors are cheaper & easy to implement. So it is better to use IR sensors.

But in case there isn't enough contrast between the surface & line (i.e. if you have a white line on dark blue surface), then it will be better to opt for LDR.

In such a case you can use a Red light as white will reflect all the light while blue will absorb ( relying on old physics rules that states that a colored surface will absorb the light of different colors, and reflect the light of the same color).

Rightly Said!!!

U PPL KNW A LOT OF STUFF . M STILL NEW TO ALL THISS

Nope, i know nothing, i am always looking to learn something new. We are still way behind when it comes to technology, and we started off knowing nothing, i had no one to guide me except this internet, i would have not know anything bout microcontrollers untill my engg if i had'nt check a circuit which had a PIC microcontroller during 12th standard. If you are curious to know and have patience to understand the no one can stop you

I have heard we do not need microcontroller for line following bot

You are right, you can manage a decent line follower with comparators and motor drivers, you do not require a Microcontroller. Its always fun to learn something new

Ya a logic gate circuitry is enough to operate a line follower.. but to make a perfect solution to deal with infinite no. of cases of path a line follower robot may encounter, the microcontroller coding is necessary.. inclusion of microcontrollers increases the efficiency of the bot by many folds

Try Searching for beam robotics. Keep it as simple as possible

What beam robotics has to do with it... here we have to track a white or a black line...

hey u don need a microcontroller to make a line follower , u ca simply make it through logic gates.The other w ay round is that you can make it using Motor drivers and comaparators or Dual H-bridge .. that is simple circuitry.. it very simple.. here nothing is to do with the beam robotcs we just have a lineto follow .. its all about reflection that matters so I think IR sensors are always better to use .. they responds fast , but I agree with the above point that .. we prefer LDR when there is a white line over blue..!!

Ya definetly it can be done by logic gates... But the one with controller and proggramming embedded into it will be more accurate and requirement specific... Because the track type also matters... The logic gate line follower will stuck if there is a break in the line...  

Yeah I just want to tell him how many ways r possible for making a line follower.. definitely the one with microcontroler n embedded would be more efficient ... than the one woth logic gates .... also .. U can make obstacle detector or edge detector just by changing .. few lines in the code... :P

Yes they are flexible too.... so for learning purpose.. Line fo;;ower is a very good project to start with...