Let's Make Robots!

laptop robot

Laptop based robot

So a friend and I are looking to utalize some of the old laptops and verious sensors he has lying around, and I've been wondering: what does one need component wise to build a rather cheap robot from a laptop? I've been reading around, but I am having a lot of trouble with it. The machine we were looking to construct is at minimum to be aproximately 2 feet tall, and the laptop's components were to be mounted inside the machine. The functions of the robot are to simply move about, and detect objects and attempt to avoid them.