TankBot Construction

To begin the construction of the TankBot, you will need to build a frame to support the RCX and the motors. As you can see, the frame is made sturdy with the use of 4 pegs to hold the beams together.

Next, add two more beams and two 2 x 8 plates. Also add the axles (note they are 12 spaces apart for the best fit of the treads).

In the next step, the 24 tooth gears are added and locked in place. Also note that additional support is added to the front with a beam and the rear with a 2 x 8 plate. I had trouble with the 24 tooth gears (the robot would run too fast and break apart when it hit something) so I used the big 40 tooth gears.

A platform is then built on the rear to support the motors. Since the motors have a round bottom, the outer edges must be higher than the center of the platform.

The motors are then placed on the platform. If you used the 24 tooth gears on the axles, you must use the 24 tooth gears on the motors or they will not fit. Likewise, if you used the 40 tooth gears on the axles, you must use the 8 tooth gears on the motors for the same reason.

Next add the RCX. Pay particular attention to the way the wires are attached. If they are not put on correctly, the motors will run backward when you program them to run forward.

The last step is to add the 1 x 6 beams to lock the RCX onto the frame, and to place the treads on the axles. If you place the tread on the hubs first and then slide the hubs on the axles, you will have better luck with this step. On the front hub, the small brushings will lock the tread in place. The rear hubs however, must be locked into place with the 16 tooth gears or the tread will not turn properly.

*pictures are from Dave Baum’s “Definitive Guide to Lego Mindstorms”