Light dependent resistor based robo.
These types of robots are used to detect the obstacle in the path and act accordingly. These types of robots are easy to make and use . As these type of robots have some practical application so it is very helpful to have such robots in your projects list.
These types of robots generally include IR sensor , Light Dependent resistor , Arduino board, battery , thesis or you can make your own body accordingly you, motor gear box , wheels ,power jack and led.
These are the list of things I would used . It may very accordingly.
But I think having such projects in your project list is helpful rather then just increasing the number of project in list.
If you are interested and want to know more about tools and procedures to make it just comment below ....