Help required - Photodiodes and object avoidance

[mayukh]

Hi, my $50 robot cant seem to avoid objects. Does the photodiode method really work as shown? I had measured the resistance of each diode in  dark and well lit areas using a multimeter, multiplied the values and found out the square root of the resultant... is that the right way to calculate the resistance needed for the diodes? Would be glad for some help here.

[SeagullOne]

From what I understand, photodiodes let the $50 robot follow a light source, not avoid obstacles...I haven't build the $50 robot though, and maybe I have this wrong.

You might upgrade to a Sharp IR rangefinder.

[cooldog]

it doesn't avoid the objects it avoids the shadows made by objects