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Lunar Rover

We're going to make a Lunar Rover out of LEGOs!  Our robot is going to have four ways that will help it through the tough terrain of the moon, sensors to help it detect everything on the moon, and a claw to pick up rock samples off the moon to bring back to Earth!  

Each step begins with a picture of all of the parts that you will need for that step.  It might help to have one person in your group get all of the parts you need, and the other putting them together, switching turns so that everyone has an equal chance to build the robot.  After that, you will read text instructions for how to put those pieces together, with pictures to help you see what it should look like.  You'll keep going, step-by-step, until you have a finished lunar rover!

Ready to get started?

Step 1:  Building the Rover's Base

Here's what you need (from left-to-right and top-to-bottom):

(2) NXT Motors
(7) 7-Beams (We count the number of pin-holes to figure out what kind of beam it is)
(1) 13-Beam
(1) 15-Beam
(14) Long Friction Pins

Take your 7 Beams and put 10 Long Friction Pins through them.  Arrange them on your table like this:

Then, put them together, so they look like this:

Take your motors and flip them over to the side that has less gray on it.  You should see two sets of pin holes on the top of the motors.  Connect the beam structure that you just made into both motors, to make a base for your rover.

Take your 13 Beam, and connect the remaining Long Friction Pins on the 1st and 3rd pin holes on either side, like this:

Then take your 15 Beam and attach it to the 13 Beam, like this.  You should see 1 extra pin hole on both sides of the 13 Beam.

Finally, connect this to your base using the pin holes on the back of the motors, like this:

Step 2:  Adding Arms to the Base

Here's what you need:

(2) 11 1/2 Double Bent Beams
(2) 3 Beams
(4) Long Friction Pins
(2) Regular Friction Pins
(4) Axle Pins (notice that they have two different ends!)

On the short end of each 11 1/2 Double Bent Beam, attach an Axle Pin and a Regular Friction Pin, like you see below.  Be careful though; the pins will need to be the opposite side of the second beam.  These are the "arms" that will be connecting the NXT brick to the base.  Check to see if you can make them look like the second picture below.

On the long end of each 11 1/2 Double Bent Beam, connect the remaining Axle Pins along with the Long Friction Pins, like this:

Then, cover the pins you just put in with the two 3 Beams.

Now, connect your two arms to the base of the robot, so they look like this:

Step 3:  Adding Powered Wheels

Here's what you need:

(2) of the wheels shown in the picture (we need this for the rough terrain on the moon!)

(2) 6-Axles (If you take a beam and measure an axle next to it, the number of pin-holes long the axle is give it its name)

(2) Full Bushings

(4) Half Bushings

Run a 6-Axle through the inside part of each wheel, along with a Full Bushing.  On the outside part of the wheel, add a Half Bushing onto the end of the axle.  Push any extra part of the axle back to the inside.  Your wheels should look like this:

Inside Part of the Wheel Outside Part of the Wheel

Attach your wheels to the motors on your robot base using the axles.  Add a Half Bushing to the inside of each motor to cover and secure the part of the axle sticking out.

Step 4:  Adding Free Wheels

Free wheels are useful because they help the robot turn.  They are called free wheels because they are made to turn and move in any direction.  While the wheels you just attached in step 3 can only go forward or backward, free wheels can go forward and backward and turn left or right.  
Here's what you need to build your free wheels:

(1) 5 Beam
(2) Hole-Hole-Axle Perpendicular Cross Blocks
(1) Axle-Hole-Axle Perpendicular Cross Blocks
(1) 6 Axle
(1) 5 Axle
(2) Regular Friction Pins
(2) Axle Pins
(2) Full Bushings
(3) Half Bushings
(1) Small Wheel

Using the 5 Axle, attach a Full Bushing, the 5 Beam, another Full Bushing, the Axle-Hole-Axle Perpendicular Cross Block, and a Half Bushing, in that order.  When you're done, it should look like this:

Now, run your 6-axle through two hole-hole-axle cross blocks, two half bushings, and a small wheel, just like in the pictures below.

Next, add your two Regular Friction Pins to the ends of the cross blocks on your wheel assembly.

Then, use these friction pins to connect the two assemblies you've made for this step.

Congratulations!  You've built a free wheel!  However, we actually need two for this step, so if you've only built one at this point, head right back to the beginning of step 4 and start on a second one!

Have two free wheels now?  Great!  Now, it's time to connect them to your robot, at the ends of the 15 Beam attached to the back of your motors, like this:

Step 5:  Building a Claw

One of the things that lunar rovers do is collect samples of objects that it finds on the surface of the moon.  We will be making a claw to collect "samples" of our own.  There will be more details on that later.

Here's what you need:

(2) 11 1/2 Double Bent Beams
(1) 5 x 3 Bent Beam
(2) 3 x 3 "T" Beams
(2) 3 Beams
(1) NXT Motor
(2) Long Friction Pins
(10) Regular Friction Pins
(2) Axle Pins
Missing from the picture:  (1) Cable

Take one of your 11 1/2 Double Bent Beams, and connect an Axle Pin and a Regular Friction Pin at the short end, like this:

Flip your NXT Motor so that the gray side is facing up.  Connect your Double Bent Beam to the right side of the motor, so it looks like this:

Next, take your 3 Beam, and connect a Regular Friction Pin and two Long Friction Pins, so it looks like this:

Then, connect your other 3 Beam, like the picture below, and add an Axle Pin.

Connect the other Double Bent Beam to this assembly.

Attach this part of the arm to the other side of the NXT motor, so it looks like this:

Now, we are going to add the two "T" Beams and the Bent Beam to help secure objects when they're picked up by the claw.  Start by taking a T Beam and connect two Regular Friction Pins in it, like this:

After counting four pinholes in from the end of your Double Bent Beam, Attach the T Beam to your claw.  Do this on both sides.

Now, take your 5 x 3 Bent Beam, and connect two more Regular Friction Pins to the shorter side, like this:

Now, attach this beam to the inside of your NXT motor, using the pin holes just above the orange rotor.

Finally, it's time to connect the claw to the robot.  We'll start by attaching two Regular Friction Pins and the Cable to the back of the motor.

And connect to the 15 Beam just above the free wheels on your robot.

Step 6:  Connecting the NXT Brick

Here's what you need:

(1) NXT Brick
(2) Cables

Before we connect our NXT Brick to the rover base, we're going to connect the two Cables to our NXT motors.  These cables will be running underneath the brick, so it'll make it easier for us to take care of those right now.

With all the cables in place, now we will put our NXT Brick in place.  See the two pins sticking out of the arms that we made earlier?  Those are going to go into the bottom two pins on the side of the NXT brick, like this:

Now it's time to connect the motors.  On the brick, there are 7 different ports you can plug into.  Motors go into the ports with letters (A, B, C), and Sensors go into the ports with number (1, 2, 3, 4).  So, we are going to plug our Cables into the letter ports.  The claw goes into Port A, the left motor in Port B, and the right motor in Port C.

Step 7:  Adding Sensors

Here's what you need:

(1) Ultrasonic Sensor (measures distance to the closest thing in front of it)
(1) Light Sensor (measures the amount of light)
(1) 3 x 3 Bent Beam with Four Snaps
(2) Regular Friction Pins
(2) Cables

Lets begin with the Ultrasonic Sensor.  On either side, connect the two Regular Friction Pins, like this:

Then, using the available pin holes on either side of the NXT brick, connect your Ultrasonic Sensor to your rover.

Now, time for the light sensor.  We are going to use the 3 x 3 Bent Beam with 4 Snaps to connect it to the robot.  Let's attach it to the sensor first, like this:

Then, on your robot, right near where your powered wheels are, the NXT brick has a couple of pinholes on the bottom, which you will use to connect your sensor to.

Now, it's time to connect your sensors to the NXT brick with the cables, so they can be used.  The ports with the letters (A, B, C) are all used, so we need to connect the sensors to the ports with the numbers (1, 2, 3, 4).  The light sensor needs to be plugged into Port 3, and the ultrasonic sensor needs to be plugged into Port 4.

There you go!  Your very own lunar rover!  This rover can detect objects in front of it, use the light sensor to detect changes in the ground below it, AND it will be able to pick up special samples from the surface with its claw!