Here is the results of several
      months of work on a new floor cleaning mechanism for the long
      lasting Sweepbot. This robot has been in operation for years
      now, sweeping up excess cat litter that manages to escape the
      litter box in the bathroom. But maintenance of the sweep mechanism
      was getting tedious, and Ive decided to make a new lower maintenance
      (I hope!) cleaning unit. Since I built the robot with a huge
      cutout in the center to put in any type of sweeper I wanted,
      it was not too bad to modify it to accept the new design. 



      
Shown at left is
      the final results of many months of experimentation, and assembly.
      Ive labeled the key components. The suction fan is from a toy
      "wall walking" spider from Radio Shack, which used
      suction to stick to the walls as you drove it around with a remote
      IR unit. I sacrificed this $10 toy to get the suction motor and
      fan out. 

      
The unit glides
      on the bathroom tile floor on Teflon guides and the dirt bin
      can be emptied while on the robot from the bottom.


Test fitting
      of the canister. It is spring mounted to float on the floor independent
      of the robot. The robot basically "pulls" it along
      as it slides on the floor. The entire top of the robot has been
      removed here for clarity.


      
Top view showing
      the fit of the final assembly. While the air intake of the sweeper
      is small, it passes over the floor many times each run which
      lasts 5 minutes. Any longer sucks the batteries down since this
      sweep motor draws 2 amps at 3 volts. To the sweepers upper left
      is the voltage controller I made from a huge NPN power transistor.
      It drops the batteries 13v down to 3.0 volts. Not an easy task
      for a 2 amp draw!

      
The NPN which is
      a 2N3055 is used as an emitter follower configuration to do this
      task. The heat sink keeps it from overheating from the 20W load.


To dump
      the bin, which is done about every two weeks, the cover plate
      on the bottom of the canister is connected by two neodymium magnets
      seen here on each side of the label. You simply pull the bottom
      off, dump it in the waste basket and snap the cover back on which
      totally seals the bottom. 

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