IR recievers for line follower?

[Xyver]

Can you use normal photoresistors (like the ones in the 50$ robot) to detect IR light?

[Soeren]

Hi,

Response will be only a few percent of what you will get with visible light if any at all. The results will vary with different LDRs, but none are really useable for IR.
Phototransistors often have their peak sensitivity at IR wavelengths, so would be a much better choice.