R/C LEGO® “The Bull” Buggy

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.
The Bull Buggy
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 the right side 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 Carprojects.

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

More photos and video in Step 13.

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

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. (4×6 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 1×4 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

[box color=”#985D00″ bg=”#FFF8CB” font=”verdana” fontsize=”14 ” radius=”20 ” border=”#985D12″ float=”right” head=”Major Components in Project” headbg=”#FFEB70″ headcolor=”#985D00″]

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.   – 1×4 Plate (#3710)
13 nos. – 1×6 Plate (#3666)

10 nos. – 2×2 Plate (#3022)
2 nos.   – 2×2 Plate Round (#4032)
2 nos.   – 2×2 Slide Shoe Round (#2654)

2 nos. – 2×4 Technic Plate (#3709)
3 nos. – 2×6 Technic Plate (#32001)
2 nos. – 2×8 Technic Plate (#3738)

3 nos. – 1×4 Technic Brick (#3701)
2 nos. – 1×6 Technic Brick (#3894)
2 nos. – 1×8 Technic Brick (#3702)
4 nos. – 1×12 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 1×8 (#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.   – 1×4 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)

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

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.)


DIY Arduino and Motor Driver PCB

XBee Module

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

Hook up Wire [/box]

Super Glue
X-ACTO Knife
Sand paper
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 1×8 Technic Bricks (#3702)

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

Photo 4, 5 Two 1×8 Technic Bricks (#3702)

Photo 6, 7 2×4 Technic Plate (#3709) and Technic Plate (#32001)

Photo 8, 9 1×2 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 1×6 Plates (#3666)

Photo 21, 22 1×4 Plate (#3710)

Photo 23, 24 1×4 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 1×4 Technic Brick (#3701) and 1×4 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 1×6 Technic Brick (#3894)

Photo 3, 4 Two 1×2 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 1×12 Technic Brick (#3895)

Photo 22, 23 Three 2×8 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 1×8 Technic Bricks (#3702)

Photo 5, 6 2×8 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 1×4 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 1×6 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.


For more detail: R/C LEGO® “The Bull” Buggy

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