Introduction: R/C LEGO® "The Bull" Buggy

About: I am Electronic Visualization Artist. I look at things through the Looking Glasses.
There are more than 20 models of LEGO®'s Dune Buggy type car, even more than the models in LEGO® Race Car category.
Dune Buggy is usually four wheels drive off road vehicle,  which would not be used on the road.

Now that I got excited on the "dune buggy", and was also inspired by 1998 LEGO®'s Turbo Command 8428/8432 (See picture 6 and 7), I designed my own buggy, "The Bull" Buggy

"The Bull" Buggy is larger, and more complicate car to build than my two other LEGO cars, R/C Lego Car (or R/C Lego Car Redux) and Wireless Lego Car. It needed bigger or more power (torque) to drive the car. So I decided to use round 24mm. diameter with 9V input power. That made me to design another version of 3D printed motor housing (See details in Step 1.)

This 3D printed motor housing was designed to be used with the Lego's parts, and compatible with Lego Modular System just like my smaller version of the motor housing for 130-type DC motor (See Step 1 of my R/C LEGO Car Redux.) 

After I built the first "Bull" Buggy, I realized that when I want to access the Palm Arduino and motor controller PCB, I had to tear apart the rear frame to get to PCBs. So I altered the design by adding the hinges to the rear frame so I can just flip the rear roll cage up instead of tear them apart (picture 2 and 3.)

The "Bull" Buggy's  features:
  • Shock absorbers.
  • The chassis is not all paralleled to ground.
  • Can be constructed without shock absorbers as an alternative, so the chassis is all paralleled to ground level. With this alteration, the motor could be mounted using the side holes on the motor housing to and connectors to mount to the LEGO bricks (photo 5, or see Step 11 for details installation)
  • Rotatable rear roll cage.
  • Switchable steering wheel. (Can be switched between the left side and therightside of the vehicle.)

Lego Bricks or parts are already reusable/recyclable products. And it could be passed on to the next generation just like all the Lego parts do. I would say this is the right way to solve the problem and more "green" than hacking toy R/C Motor housing, like I did earlier with R/C Lego Car and Wireless Lego Car projects.

For the wireless control, I used XBee module as an alternative) for controlling the car wirelessly, similar to my previous cars, R/C Lego Car, Wireless Lego Car, Ford Mustang Arduino Controlled R/C Car. (Picture 8)

More photos and video in Step 13.


Disclaimer:
LEGO®, TECHNIC, are property of The LEGO Group of Companies (http://www.lego.com), which does not sponsor, own, authorize or endorse this creation.

Step 1: 3D Printed Motor Housing

Why 3D Printed Motor Housing?

As I mentioned in R/C LEGO Car Redux, I was not very happy and was tired of using hacked motor and motor housing from toy car or toy R/C car, because each time I want to build a different design Lego Cars. Most of the time the new design Lego car that I plan to make was not able to use the previous hacked motor and motor housing.

This 3D Printed motor housing is the second version of the 3D printed motor housing. The design and 3D modeling processes were also done in 123D Design.

This 3D Printed motor housing fits most of 24mm. diameter DC motors with 2mm shaft diameter.

The motor housing was designed to have studs that compatibles with Lego modular system. (4x6 studs.)

This version has better advantage than the first version since we could secure the motor housing with the Technic Brick by using the holes on the sides of the motor housing (See Photo 20, 21, 22)

This 24mm. motor housing is a lot sleaker than the 130-type DC motor housing, and it used less material than the 130-type motor housing.

Attached is the STL file, you download below. Or in case if you do not have a 3D printer, you can view the model or have it made at Shapeways, here.

It is a good value for the long run. My motor housing for Lego car design can be used over and over, and I do not have to buy toy R/C car to hack for motor housing from it and mod it to fit with my new design Lego car anymore.

Design Processes and 3D Modeling

Photo 1 Shows finished  3D model of motor housing with the 1:1 scale 3D model of 24mm. diameter motor. 

Photo 2 I created 1:1 scale 3D model using 123D Design from the manufacturer datasheet. Then saved to my models library.

Photo 3 I inserted the 4-stud LEGO Technic Brick (1:1 scale) that I have in my 3D models library. (Note: I hid the motor for clarity.)

Photo 4 I used The Patterns Tool in 123D Design to create the second Technic 1x4 stud brick.

Photo 5, 6, 7 I created the housing for the motor, using Primitives Tool in 123D Design and the Modify Tool to create the housing for motor.

Photo 8 I added opening by using Combine-Substract tool to the surface for fingers to push in or pull out the motor.

Photo 9 The final 3D model before combining the LEGO Bricks and the housing together.

Photo 10 The final 3D model after combining the LEGO Bricks and the housing together.

Photo 11 The finished 3D model of the motor housing with the motor. Then checked to see if the motor fit into the void area.

Photo 12 I rotated 3D Printed Motor Housing 90 degree to make the model have more strength while the model get print.

Photo 13 I hid the motor model before export to stl format before send the model for printing.

Photo 14 Different view angle (from the bottom) of the 3D model.

Photo 15, 16 The real 3D Printed Motor Housing.

Photo 17 Assembled motor housing ready to use. See details installation in Step 11.

Photo 18 3D Printed Motor Housing in used.

Step 2: Parts and Tools

Following is the list of Lego Technic parts that I used for building this "The Bull" Buggy.
If you want to do this project you could use the differenct color for the car.

Note: The number in the bracket is the Lego's Design ID.

Lego Parts

6 nos. - Pole Reverser Handle(#6553)
4 nos. - Perpendicular Axle Connector (#32039)
1 no.   - Perpendicular Axle/Pin Connector with double Split (#41678)
8 nos. - Axle Joiner (#6538b)
2 nos. - Axle Pin Connectors (#32184)

4 nos. - Angle Element [1], 0 Degrees (#32013)
6 nos. - Angle Element [3], 157.5 Degrees (#32016)
2 nos. - Angle Element [4], 135 Degrees (#32192)
4 nos. - Angle Element [5], 112.5 Degrees (#32015)
2 nos. - Angle Element [6], 90 Degrees (#32014)

2 nos. - 6.5L Shock Absorber (#731c01)

2 nos. - Car Seat (#2717)
8 nos. - Perpendicular Axle Pin Connector (#6536)

2 nos.   - 1x4 Plate (#3710)
13 nos. - 1x6 Plate (#3666)

10 nos. - 2x2 Plate (#3022)
2 nos.   - 2x2 Plate Round (#4032)
2 nos.   - 2x2 Slide Shoe Round (#2654)

2 nos. - 2x4 Technic Plate (#3709)
3 nos. - 2x6 Technic Plate (#32001)
2 nos. - 2x8 Technic Plate (#3738)

3 nos. - 1x4 Technic Brick (#3701)
2 nos. - 1x6 Technic Brick (#3894)
2 nos. - 1x8 Technic Brick (#3702)
4 nos. - 1x12 Technic Brick (#3895)

4 nos. - Technic Level 3M (#6632)

12 nos. - Bush for Cross Axle (#6590)
12 nos. - Connector Peg/Cross Axle (#6562)
2 nos.   - Cross Axle 3M with Knob (#6587)
30 nos. - Connector Peg (#3673)
                 Connector Peg with Friction (#2780)
2 nos.   - 2M Friction Snap w/Cross Hole (# 32054)
8 nos.   - Connector Peg with Knob  (#4274)
2 nos.   - Connector Peg 3M (#32556)

10 nos. - Cross Axle 4M (#3705)
8 nos.   - Cross Axle 6M (#3706)
4 nos.   - Cross Axle 8M (#3707)
2 nos.   - Cross Axle 2M with Groove (#32062)

2 nos. - Cross Axle 3M (#4519)
? nos. - Cross Axle 5M (#32073)

1 no.   - Ribbed 7 mm Dia. Tube 9L (#78c09)

2 nos. - Rigid Tube 3 mm Dia. 10L  (#75c10)
2 nos. - Rigid Tube 3 mm Dia. 17L (#75c17)

Steering Kit
1 no.    - Steering Wheel Ø16 F/Console 2X2 (#30663)
2 nos. - Steering Arm with Two Pins (#32069)
1 nos. - Gear Rack 1x8 (#6630)

1 no.   - 8-Tooth Gear (#3647)
2 nos. - Perpendicular 3L Pin/Axle Connector (#32068)
2 nos. - Cross Axle 3 with Knob (#6587)
1 no.   - 1x4 Flat Tile (#2431)

Gear Kit
1 no. - 24-Tooth Crown Gear Type III (#3650)

Wheels and Rims
4 no. - Tires (Balloon) size 43.2 x 28 S (#6579)
4 no. - Wheel 43.2 x 28 Balloon Small 1-3/16" (30.2mm) (#6580)

Servo
9g Micro Servo (T Pro SG90) or similar.

Motor
LEGO compatible Motor Housing for Round 24mm dia. 9V motor. (STL file can be downloaded below)
or if you do not have 3D Printer (I wish I have one too!) You could order one from Shapeways, here.)

Round DC Motor: 9V, 24mm in diameter.

Two M2.3, 4 mm long round head screws (if not come with the 9V, 24mm. dia. round motor.)

Others

DIY Arduino and Motor Driver PCB

XBee Module

XBee breakout board (I used XB-Buddy Basic Kit, Jameco Part no. 2163680)

Hook up Wire

Tools
Super Glue
X-ACTO Knife
Sand paper
Files
Hand Drill & bits

Step 3: Steering System

In this Step, I'm going to show you how to construct the car Steering System.
I also added the description text on each image.

Following is the list of parts used in each step.

Photo 1 Two 1x8 Technic Bricks (#3702)

Photo 2, 3 Four Connector Peg with Friction (#2780)

Photo 4, 5 Two 1x8 Technic Bricks (#3702)

Photo 6, 7 2x4 Technic Plate (#3709) and Technic Plate (#32001)

Photo 8, 9 1x2 Technic Brick with 2 holes (#32000)

Photo 10, 11 Two Steering Arm with Two Pins (#32069)

Photo 12, 13, 14 Two Cross Axle with knob (#6587) and two Perpendicular 3L Pin/Axle Connectors (#32068)

Photo 15, 16 Two Bush for Cross Axle (#6590)

Photo 17, 18 Two Connector Peg with Cross Axle (#6562)

Photo 19, 20 Two 1x6 Plates (#3666)

Photo 21, 22 1x4 Plate (#3710)

Photo 23, 24 1x4 Flat Tile (#2431)

Photo 25, 26 Steering Arm with Two Pins (#32069)

Photo 27, 28 Servo with modified support plate

Photo 29, 30, 31 Servo horn glued to the 3L Axle with knob (#6587) and Bush for Cross Axle (#6590)

Photo 32, 33 1x4 Technic Brick (#3701) and 1x4 Plate (#3710)

Photo 34, 35, 36 8-Tooth Gear (#3647)




Step 4: Front Bumper and Battery Compartment

In this Step, I'm going to show you how to construct the car Front Bumper and Battery Compartment.

Photo 1, 2 Two 1x6 Technic Brick (#3894)

Photo 3, 4 Two 1x2 Plates (#3023)

Photo 5, 6 Two 1x2x2 Corner Plate (#2420)

Photo 7, 8 Axle Joiner (#6538b) and Two Cross Axle 4M (#3705)

Photo 9, 10, 11 Two Pole Reverser Handle (#6553) and two Perpendicular Axle Pin Connector (#6536)

Photo 12, 13, 14 Perpendicular Axle/Pin Connector with double Split (#41678) and Cross Axle 4M (#3705)

Photo 15, 16, 17, 18 Two Connector Peg with Friction (#2780)

Photo 19, 20, 21 Four Connector Peg with Friction (#2780) and two 1x12 Technic Brick (#3895)

Photo 22, 23 Three 2x8 Technic Plates (#3738)

Photo 24, 25 Two Tires (Balloon) size 43.2 x 28 S (#6579) and two Wheel 43.2 x 28 Balloon Small 1-3/16" (30.2mm) (#6580)

Step 5: Gear Box

In this Step, I'm going to show you how to construct the car Gear Box.

Photo 1 Continue from previous step

Photo 2, 3, 4 Four Connector Peg with Friction (#2780) and Two 1x8 Technic Bricks (#3702)

Photo 5, 6 2x8 Technic Plate (#3738)

Photo 7, 8 Cross Axle 8M (#3707) and Bush fro Axle (#6590)

Photo 9, 10 24-Tooth Crown Gear Type III (#3650)

Photo 11, 12, 13 Axle Joiner (#6538b) and Cross Axle 6M (#3706)

Photo 14, 15, 16 Two 1x4 Technic Brick (#3701)

Photo 17, 18, 19, 20  3D Printed Motor housing, 24 mm. dia. 9V DC motor, Modified Connector Peg/Cross Axle (#6562) to fit the shaft of DC toy motor. (I used Pololu part #1001), and 8-Tooth Gear (#3647)

Photo 21 Assembled motor housing

Photo 22, 23 Place the assembled motor as shown.

Photo 24, 25, 26 Four 1x6 Plates (#3666)

Photo 27, 28 Two Tires (Balloon) size 43.2 x 28 S (#6579) and two Wheel 43.2 x 28 Balloon Small 1-3/16" (30.2mm) (#6580)

Photo 29, 30 Two Bush for Cross Axle (#6590)

Photo 31, 32 Done with the gear box and lower frame.

Step 6: Palm Arduino V3 & Motor PCB

In this Step, I'm going to show you how to construct the car Palm Arduino and Motor PCB.

Photo 1 Continue from the previous step

Photo 2, 3, 4, 5, 6 Two 1x6 Technic Bricks (#3894) and four 1x6 Plate (#3666)

Photo 7, 8 Two 1x12 Technic Bricks (3895) and 2x6 Technic Plate (#32001)

Photo 9, 10 Four Connector Peg with Friction (#2780) and Two 1x4 Technic Bricks (#3701)

Photo 11, 12 Two Connector Pin with Friction  (#2780)

Photo 13, 14 Two Axle Joiner (#6538b) and Cross Axle 2M with Groove (#32062)

Photo 15, 16 Two Cross Axle 3M (#4519)

Photo 17, 18 Two Bush for Cross Axles (#6590)

Photo 19 The installation of the Palm Arduino and Motor Controller Base.

Photo 20, 21 Two 6.5L Shock Absorber (#731c01)

Photo 22, 23 Two 1x6 Technic Brick (#3894)

Photo 24, 25 Two 2x2 Plates (#3022) and two 1x4 Technic Bricks (#3701)

Photo 26, 27 Two 1x1 Technic Brick with 1 knob (#87087)

Photo 28, 29, 30 Two Technic Level 3M (#6632) and four Connector Peg/Cross Axle (#6562)

Photo 31, 32 2x8 Technic Plate (#3738)

Photo 33, 34 Four 1x1 Round Plates (#6141)

Photo 35 This photo shows the connection of Arduino and Motor Controller PCB and motor, 3.7V battery for Arduino and XBee module, Servo, and 7.4V battery for motor. On the PCB there is 5V regulator for Servo power supply.

Step 7: Side Roll Cage and Steering Wheel

In this Step, I'm going to show you how to construct the car Side Roll Cage & Steering Wheel.

Photo 1 Continue from last Step.

Photo 2 Seat (#2717)

Photo 3, 4 Two Connector Peg with Friction (#2780)

Photo 5, 6, 7, 8 Seat (#2717)

Photo 9, 10 Four Connector Peg/Cross Axle (#6562)

Photo 11, 12 Two Friction Snap w/Cross Hole 2M (# 32054)

Photo 13, 14 Two Connector Peg 3M (#32556)

Photo 15, 16 Bush for Cross Axle (#6590) and Cross Axle 8M (#3707)

Photo 17, 18 Two Perpendicular Axle Pin Connector (#6536)

Photo 19, 20 Technic Bush 1/2 Toothed Type II (#4265b)

Photo 21, 22 Cross Axle 6M (#3706) and Bush for Cross Axle (#6590)

Photo 23, 24, 25, 26 Axle Joiner (#6538b)

Photo 27, 28 Bush for Cross Axle (#6590) and Cross Axle 6M (#3706)

Photo 29, 30 Perpendicular Axle Pin Connector (#6536)

Photo 31, 32, 33 Steering Wheel Ø16 F/Console 2X2 (#30663) and Cross Axle 8M (#3707)

Photo 34, 35 Perpendicular Axle Pin Connector (#6536)

Photo 36, 37, 38, 39 Technic Bush 1/2 Toothed Type II (#4265b)


Step 8: Driver Compartment

In this Step, I'm going to show you how to construct the car Driver Compartment.

Photo 1, 2 Two Angle Element [1], 0 Degrees (#32013) and Two Cross Axle 3M (#4519)

Photo 3, 4 Two Angle Element [5], 112.5 Degrees (#32015)

Photo 5, 6 Two Cross Axle 6M (#3706)

Photo 7, 8 Two Angle Element [6], 90 Degrees (#32016)

Photo 9, 10 Two Cross Axle 4M (#3705)

Photo 11, 12 Two Axle Connector (#3651)

Photo 13, 14, 15 Installation of two side roll cages.

Photo 16, 17, 18 Two Angle Element [1], 0 Degrees (#32013), Two Cross Axle 8M (#3707) and Two Angle Element [3], 157.5 Degrees (#32016)

Photo 19, 20 Cross Axle 12M (#3708) and Two Liftarm 1 x 2 Thick with Pin Hole and Axle Hole (#60483)

Photo 21, 22, 23, 24 Two Technic Level 3M (#6632) and Cross Axle 6M (#3706)

Photo 25, 26 Axle Joiner (#6538b)

Photo 27, 28 Two Technic Level 3M (#6632)

Photo 29, 30 Cross Axle 6M (#3706)

Photo 31, 32, 33 Cross Axle 6M (#3706) and Perpendicular Axle Connector (#32039)

Photo 34, 35 Perpendicular Axle Connector (#32039)

Photo 36, 37, 38 Four Bush for Cross Axle (#6590)



Step 9: Rear Roll Cage

In this Step, I'm going to show you how to construct the car Rear Roll Cage.

Photo 1, 2 Two Angle Element [3], 157.5 Degrees (#32016) and Two Connector Peg with Knob  (#4274)

Photo 3, 4 Two Cross Axle 5M (#32073)

Photo 5,  6 Two Cross Axle 4M  (#3705)

Photo 7, 8 Two Angle Element [5], 112.5 Degrees (#32015)

Photo 9, 10 Two Cross Axle 3M  (#4519)

Photo 11, 12, 13 Two Rigid Tube 3 mm Dia. 10L  (#75c10) and two Connector Peg with Knob  (#4274)

Photo 14, 15 Two Connector Peg with Knob  (#4274)

Photo 16, 17 Two Cross Axle 4M (#3705) and Two Angle Element [3], 157.5 Degrees (#32016)

Photo 18, 19 Two Cross Axle 5M (#32073)

Photo 20, 21 Two Angle Element [1], 0 Degrees (#32013)

Photo 22, 23 Axle Joiner (#6538b)

Photo 24, 25, 26, 27 Show the installation of the rear roll cage.

Step 10: Front Roll Cage

In this Step, I'm going to show you how to construct the carFront Roll Cage.

Photo 1, 2, 3, 4 Two Rigid Tube 3 mm Dia. 17L (#75c17), Four Connector Peg with Knob  (#4274) and Four Perpendicular Axle Pin Connector (#6536)

Photo 5, 6 Two Pole Reverser Handle (#6553)

Photo 7, 8 Two Liftarm 1x2 Thin (#41677)

Photo 9, 10, 11, 12, 13 Two 2x2 Slide Shoe Round (#2654), Two Cross Axle 2M with Groove (#32062), Two 2x2 Plate Round (#4032) and Two Pole Reverser Handle (#6553)

Photo 14, 15, 16 ,17 Two Cross Axle 4M (#3705), Two Connector Peg/Cross Axle (#6562) and Ribbed 7 mm Dia. Tube 9L (#78c09)


Step 11: Alternative Chassis

This Step shows an alternative way to install the motor housing. by using the provided holes as the way to connect to LEGO® components instead of studs on top of the brick.
This was we do not needed the shock absorbers. And the car chassis will be parallel to the ground.

From Step 5

Photo 1, 2
 Shows the motor housing installed by default.

Photo 3, 4, 5 Two 1x8 Technic Bricks (#3702) and Two connectors with friction  (#2780)

Photo 6, 7 Two 1x6 Technic Bricks (#3894)

Photo 8, 9, 10, 11 Assembled motor housing and Four Connector Peg 3M (#32556)

Photo 12 Assembled rear wheels and 24-Tooth Crown gear.

Photo 13 Shows the motor housing installed.

Photo 14 Assembled Palm Arduino and motor controller (L293D) PCB base.

Photo 15 2x8 Technic Plate to replace the cross axle.

Photo 16 Add the Rear Roll Cage.

Photo 17 Side view of straight chassis.

Step 12: Processing User Interface & Arduino Sketch

Processing Sketch

I used similar Processing GUI from my previous instructable, Processing Controls R/C Car with XBee modules.
I changed the background image to the suitable image. I took a photo of the finished "The Bull" Buggy. Then I removed the front wheel.
And adjust the location of the turning wheels in the sketch.
The background image of this R/C Lego is a little bit smaller than the Ford mustang Shelby. So, I needed to re-specified the location of the front wheels and the gears icon. But that is not very hard thing to do.

Arduino Sketch

I also modified the Arduino sketch so that the Arduino could control the servo to turn properly.

I used the digital pin 10 (on Arduino) for the servo control.
For the motor, I used pin 9, 8, and 7 (on Arduino) to drive L293D motor driver.

Included below is the zip file of Bull Buggy Control Processing Sketch, and Bull Buggy Arduino Sketch.

XBee Configuration

For the XBee Configuration Procedures on MacOS, see Step 10 of Processing Controls R/C Car with XBee modules.
Or see Step 13 of Make Wired Robotic Arm Edge to "Wireless" with DIY Arduino + XBee for Windows XP.

Step 13: Photos and Video

Gallery of photos of the finished "The Bull" Buggy

Photo 1 - 5 Design at sketch stage. At this stage I was not thinking about the way to access the Arduino and motor controller PCB on the back.

Photo 6 The Bull Buggy (Sketch stage) posted with it relatives, the R/C Car, and the Wireless R?C Race Car.

Photo 7 - 19 The Bull Buggy final stage ready for the test.

Photo 20 - 25 Show the rotatable rear frame. So I can access to the Palm Arduino V3 and motor controller PCB on the back without tearing the component apart.

Video
- Test run no. 1





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