Build a Very Small Robot: Make The World's Smallest Wheeled Robot With A Gripper.

Step 2 Build a 1/20 Cubic Inch Robot.

At .40"x.50"x.46" the robot volume of the Magbot R-20 is slightly less than 1/20 of a cubic inch. It is made by folding 3 box structures of non magnetic sheet metal. The smallest inner box is soldered to the left finger of the gripper. two small magnets are epoxied to the vertical shaft which bends to form the right finger of the gripper which rotates freely. It is these two magnets which are controlled by an external moving rotating and spinning magnetic field that provide all the power to the robot.

I used .005" thick phosphor bronze sheet metal for the box structures because it can be soldered and dousnt oxidise or tarnish easily. Copper or brass could also be used. I originally used small drill bits to drill the bearing holes in the sheet metal for the rotating wire shafts. After breaking a few of them in a drill press, I ended up just punching holes with a large needle and hammer into the sheet metal. This creates a cone shape hole which can then be filed flat. The holes do not have to be a precise size or even perfectly placed. At this small a scale, the frictional forces are minute and if you look closely at the pictures you will see I used long .1" standard long header pins which are square, for the shafts and gripper fingers. Copper wire could also be used.

The glass bead wheels were mounted on brass pins epoxied to the bottom of the robot. It is important to use non magnetic materials for the construction or the power and control of the robot will be adversely affected.