Our robot uses two carefully-chosen sensors: the touch and the light sensor.

The light sensor is on the side to see the different colors of the medicine bottles.

We put the touch sensor on the back so Alfred would know when he was going into a wall; backing into a wall is a useful  method of ensuring Alfred stays on its' path.

Alfred is a very versatile robot with a lot of interesting characteristics; he's tall and skinny, with the NXT mounted on top.

These slides explain why.

Alfred is skinny so it can fit through small spaces.

This results in him being quite tall; however, by distributing the weight carefully, he is quite stable.

We put the NXT intelligent brick on the top so it we can easily access to do tasks fast.

Alfred is a very unique robot, especially in terms of how it moves. It has a ball in the back for frictionless turning, as well as two large wheels for quick movement.

We have two different motors - one for each wheel, so it can turn, of course.

We put our last motor on the front to have reachers and 

grabbers. The front motor is centered so the robot isn't side-heavy, which would make more likely to tip over.  

This addition to our robot allows turning to be easy.

This lets the robot turn with as little friction as possible.

We picked our wheels - the largest Lego wheels we could find - for the right tradeoff between speed and control.