I designed this robot my first year when I was teaching my team to program. We needed a simple robot with all the sensors. We could build this robot quickly and spend our time learning software.

This robot has many faults that make it unsuitable for an actual FLL challenge. These include but are certainly not limited to:

1. Robot does not drive straight.
2. Light sensor is adjustable but rather frail.
3. Touch sensor is not connected to anything real.
4. Rotation sensor is not geared up to improve accuracy.
5. Robot is fairly slow.

The following instructions where generated with MLCAD. For those that wish, here is the data file. sw-robot.ldr

1) Start with two 16 stud long beams. Pin them together with two black friction pins at each end. Make two assemblies.

2) Bridge between the beam assemblies with two 2*8 plates.

3) Add two 1*8 plates at each edge of the previous 2*8 plates. Add a 2*2 plate between the 1*8 plates on each side. You should have make a shallow pool.

4) Add two motors. The above pool was needed to accept the half round protrusion on the bottom of the motor.

5) Tie the two motors together with 2 2*4 plates.

6) Add the RCX and a 2*6 plate to tie in the motors.

7) Add an 8 tooth gear to each motor. Slide a 40 tooth gear onto a 8 stud long axle. Place axle into the third hole in the beam. The 8 and 40 tooth gears should mesh. Add a bushing to the axle on the inside of the beam. Adjust the gear position to have the axle flush with the bushing (most of the axle sticks out for the wheels). Make a second assembly for the other side.

8) Slide a bushing onto the axles next to the gears. These are spacers for the wheels. One each side.

9) Slide a 40 tooth gear onto a 6 stud long axle. Place this into the 8th beam hole. The two 40 tooth gears should mesh. Add a bushing to the axle on the inside. This is done only on the right side in preperation for the rotation sensor.

10) Slide a rotation sensor onto the axle with the wire facing away from the wheels. Connect its wire to port 3. Add a 2*4 plate onto the sensor such that ½ hangs off the front. Add a 1*2 brick with axle hole (the plus shape hole) to the bottom of the overhanging 2*4 plate.

11) Take a 6 stud long axle and push it into the above 1*2 brick with axle hole and into the appropriate hole in the main beams. Add a bushing to the axle on the inside to hold it in place. This keeps the rotation sensor in place.

12) Add a 2*2 brick to the underside of each main beam. These should be flush with the front edge. Bridge across the robot with two 2*8 beams. These connect to the bottom of the previous 2*2 bricks. Now add the 2*2 'boat' to the center of the two bridging beams. The 'boat' is a 2*2 round plate that is dished. It is often used as a caster. Why LEGO called this part a 'boat' is beyond me! I tend to think of it as a 'button'.

13) We now make the light sensor assembly. Add two green 1*2 bricks with axle hole to the top of the light sensor connector. Stick an 8 stud long axle into the bricks. Slide a ½ bushing onto the axle. Now slide on a 2*8 plate with the studs facing away from the green bricks. Add a full bushing onto the axle. Make sure the scallops on the bushing point towards the green bricks. You will find that the scallops allow the plate to snap onto the bushing! Lastly connect the light sensor to the 2*8 plate. It should overhang by 2 studs. The hole assembly can now be connected to port 2 of the RCX.

14) Add the medium balloon wheels.

15) Now add short wires from the left motor to port A and the right motor to port C. In each case the wire should exit off the side of the robot like in the picture. Placing the wires in other orientations can lead motors to rotate the 'wrong' directions. Finish up with a short wire from port 1 to a touch sensor you can stick just about anywhere.

Home