This is a Flexpicker.  Flexpickers are normally used in the industry
for things like putting food in packaging, sorting small items, etc...

Mine is made with LEGO MindStorms and sorts colored blocks.  It uses 2 NXTs and 2 RCXs.

The NXTs communicate via Bluetooth.  NXT 1 and RCX 1 communicate via infrared.  RCXs
have it built in.  The NXT uses a custom built sensor from HiTechnic called the "IRLink"
to do that.  RCX 2 is stand-alone and dos'nt need to communicate.

1 RCX controls the brick dispenser, and the angled conveyor.

The second RCX controls the pneumatic compressor.  To detect the pressure, it has a
piston that has rubber bands that hold it down, so that when there is enough air pressure,
then it extends and hits a touch sensor.

The 1st NXT senses the color of the block, tells the 1st RCX what to do, sends the color
data to the NXT controlling the arm, controls the main conveyor, and the smaller 2
conveyors in the back.  It also activates the switch for the pneumatic claw on the arm.
The switch is operated through a "Power Functions IR Reciever" which the IRLink can 
control also.

The 2nd NXT controls the movements of the arm.