Mission to Mars 4 Wheel Rover Build Instructions April 2008

FRODO the NXT Rover Modular design 4 wheels with differential drive –Turns left, right, goes forward and reverse Front collision avoidance detection bumper –Left, right, both Light sensor for path detection in front –Protected from ambient light Rear wheel to maintain balance Rover frame decoupled from NXT controller –Controller may be easily removed from rover (2 pins) ½” clearance from ground Can climb obstacles up to ¾” high Location for rock capture device Rock deflector in front

Light Sensor Assembly 1A, B: Insert 2 3X pins into the frame of the light sensor. 2A, B: Attach 3x5 lift arms to each side of the sensor. 1A1B 2A2B

3A, B: Using regular pins, fasten 2 1x9 lift arms to the sides of the 3x5 lift arms. 4A, B: Attach 4 more regular pins into the 1x9 lift arms. These will be used to secure the assembly to the rover’s frame. 3A 3B 4A4B

Front Collision Avoidance Bumper 6: Push 2 2x notched axles into the center 3x connector. 7: Push 2 pin axles into each of the other two 3x connectors. 5A 5A,B: Position 2 1x9 lift arms and 3 3x connectors, as illustrated: 5B 67

8A, B: Push 2 4x axles into the top 3x connector, and 2 3x axles at the other end of the same connectors. 9: push 2 regular pins into the center holes of the top connectors. 10: Slip a 4x5 bent lift arm onto the axles and pins. This forms one side of the rock deflector. 8A8B 910

12: Attach the other side of the rock deflector and cap the axle ends with full bushings. 13: Attach 2 1x9 lift arms to the casing of the touch sensors with 4 regular pins. 11A11B 11A, B: Push the axle pin onto the ends of the 2 touch sensors

Rear Wheel for Balance 14: Begin the assembly by pushing 4 regular pins (2 at each end) into a 1x9 lift arm. Then push one 3x pin in hole 3 and one in hole 7. 15: Attach a 90-degree connector to each of the 3x pins. 16: Insert 2 2x notched axles. 17: Install a 4-way connector between the 2 90-degree connectors, and secure it with the notched axles

18A, B: Create a pivot point with a 5x axle that is held in place with a ½ bushing. Push a 4-way pin piece onto the free end of the axle. 19A, B: Make a fork with two 3x5 lift arms, by attaching them to the 4 way pin piece. Then insert two small wheels between the fork and secure them with a 3x axle. 18A18B 19A19B

Differential Drive Unit (2 units are required; these instructions are for the right-hand unit) 20A, B: Begin the assembly with two 1x16 beams and one 1x4 beam. Position the motor so as to line up the holes in the back of the casing with the last 3 holes of the top 1x16; the motor’s axle hole should line up with the middle hole of the 1x4. 21A, B: Fasten the motor to the frame with 3 regular-size pins at the back of the frame. Then slip a 4x axle through the 1x4 into the axle hole of the motor. Attach a 24-tooth spur gear to the axle. 20A20B 21A21B

22A, B: Push 2 axle pins, one to the left and one to the right of the spur gear, into the 1x16 beam. Then insert 2 4x axles into the bottom beam in holes 6 and 14. Cap the inside end of these axles with full bushings. 23A, B: Push a 24-tooth spur gear onto each of the two axles. Slip 2 ½-bushings onto each axle, and position them so that they sit next to the 24-tooth gear. Install 2 small double-bevel gears onto each axle pin. Finally, push a wheel onto each of the axles.  Repeat this procedure to assemble the left-hand Differential Drive unit. 23A23B 22A22B

Module Assembly 24A, B: Begin the rover assembly with the drive units. (NOTE: only one unit is shown here). Attach the back wheel to the casing of the motors, making sure that all 6 pins are properly inserted. 25: Attach the bumper assembly to the motors with 2 pins on each motor. Temporarily remove the bumper from the touch sensors. 26: Slide the light sensor assembly between the motors and attach it to the motors and bumper. 24A 24B 2526