It uses 3 sensors .i.e. 1 SRF05 and 2 GP2D12 to detect objects and decide whether the object should be picked up or it should be avoided. GP2D12 were not stable enough so i soldered 50uF capacitors between the ground and Vcc.
I used a 10 RPM Dc gear motor for the arm. It gives around 8-9 Kg of torque at 9V. For using this motor i used a L293D motor driver other than the one in main board and made connections on the breadboard.
Since i didn't had any of the digital outputs left i used the digital inputs and converted them to digital outputs for controlling the arm motor