HOG, BT Controlled Robot *Updated*




About: Think, make, test, write, repeat

In these instructables we will show you, how to make 3d printed tank with catapult. We were working on this project more than 500 hours, and we will keep updating it with better versions. We named it "HOG".

You can use our tracks for any project, catapult is only an add-on, and you dont need to print one, if you only need them. But this is not regular catapult - it is semi-automatic. It fires ping pong balls and can reload 3 times. Its range is somewhere around 3 meters. We used three servo motors, to achive that. It is powered by two 18650 batteries. We are using arduino NANO microcontroler. To make it easy to control and drive, we made app, wich you can download to your Android device. You can connect to HOG by Bluetooth.

In next steps we will show you how to assemble, program and drive HOG. We draw it in two different programs, Fusion 360 and Solid Works to see the difference between them.

If you want to see more project like that, vote for us!

Step 1: Parts:

We made two desings. First one is made with Fusion 360 and second one is made with Solid Works. Both designs are very similar so you can use same assembly instrustions for both.

For tank tracks you need following parts:

  • Part1 (68)
  • Part2 (2)
  • Part3 (2)
  • Part4 (2)

If you want to add catapult on it, you'll need these parts:

  • Part5 (2)
  • Part6 (1)
  • Part7 (1)
  • Part8 (1)
  • Part9 (1)
  • Part10 (1)
  • Part11 (1)
  • Part12 (1)
  • Part13 (1)
  • Part14 (1)
  • Part15 (1)
  • Part16 (1)
  • Part17 (1)
  • Part18 (1)

You'll also need:

  • M3 x 15mm screw ((77))
  • M3 x 130mm screw rod ((4))
  • M3 Nuts ((47))
  • M3 x 10mm screw ((6))
  • M3 x 40mm screw ((2))
  • M4 x 15mm screw ((7))
  • M4 Nuts ((3))
  • M5 x 160mm screw rod ((1))
  • M5 Big washer ((6))
  • M5 Self locking nut ((2))
  • M5 Nuts ((7))

Special equipment:

  • Glue for screws (Loctite 243 or similar)

Step 2: Assembly

Use photos above for instructions. You can also download .ZIP file with same photos for offline work.

Step 3: Drawing

We are experienced designers in Solid Works and we had no problems using Fusion 360. The two programs are very similar and functions are almost identical. We made two .GIF images in which we are drawing Part3 in Solid works (gif1) and Fusion 360 (gif2).

We added .f3d files, so you can modify HOG at your computer in Fusion 360.

We didn't create models for servo motors ourself, we downloaded them from GRABCAD.

Step 4: Circuit

We have designed electronic circuit in program Sprint-Layout 6.0.

Circuit in the gif and the one in picture may not match. The one in the pictures is most recent.


  • Servo (Reload): D5
  • Servo (Triger): D6
  • Servo (Charge): D3
  • Buzzer (Horn): D4
  • Driver (D12, D11, D10 , D9)
  • Motion sensor: D2
  • Ultrasound sensor: (D7, D8)
  • Bluetooth (RX, TX)

To make one you need:

  1. Arduino Nano (1)
  2. Fuse holder (1)
  3. Stepdown LM2596 (1)
  4. Bluetooth (1)
  5. Buzzer (1)
  6. Microswitch SS12D00G3 (3)
  7. H bridge L9110S (1)
  8. PCB Terminal Block Connector (4)
  9. HC-SR04 Ultrasonic Module (1)
  10. HC-SR501 Motion detector (1)
  11. Breakable pin male header Iron for PCB board
  12. 10 kohm resistor (3)

We added .lay6 file and .pdf. You can open .lay6 file in Sprint-Layout 6.0, but we will show you how to make PCB from .pdf, which contains image of the circuit design.

How to make PCB from .pdf file:

  1. Download "Circuit_on_paper.pdf" file to your computer.
  2. Print it on A4 paper (do not scale it!!!).
  3. Tape peace of waxed paper over your circuit on A4 paper (we are using leftover sticker paper).
  4. Cut your PCB plate (65mm x 80mm)
  5. Print PCB design on waxed paper.
  6. Press your paper to PCB plate with heated iron.
  7. Etch your pcb.

Step 5: Program

We wrote program in Arduino IDE.

As you can see we added PWM for motor control, but we are not using it because motors are too weak for that.

Step 6: Android Aplication

We made our android aplication in MIT App Inventor 2. There is a tutorial.

  • Download and instal Hog1.2.apk on your android device
  • Turn bluetooth on
  • Run HOG aplication
  • Connect to your HOG with buuton (Click here to connect)
  • Drive!

Step 7: Conclusion

If you want to see more project like that, vote for us!

We made this small robots to have fun and to learn new things. One of those was Fusion 360, which was very easy to learn.

Robots came out great.They are a lot of fun driving them arround. But they do need some updates. For example, motors that we used in this project are too weak. Hopefully we'll make some updates soon. Enjoy more HOG videos.

Step 8: Update (30.4.2017)

In these update we drive our tracks with 2 micro servo motors. You need to remake them from servo to dc motors (TUTORIAL). Servo motors are a little bit slower but they work fine. We added wiring diagram (Watch circuit)

You need following parts:

- 9G Micro servo motor ((2))

- M3 x 10mm screw ((2))

- New stl files

Robotics Contest 2017

Second Prize in the
Robotics Contest 2017

Design Now: In Motion Contest

Second Prize in the
Design Now: In Motion Contest



    • Make it Glow Contest 2018

      Make it Glow Contest 2018
    • First Time Author

      First Time Author
    • Big and Small Contest

      Big and Small Contest

    25 Discussions


    Question 3 months ago on Step 5

    have build hog, but battling to load, the servo that holds the fire arm goes to close before arm has loaded down, cant seem to get it to wait untill arm is down before going holding fire arm, tried different time on code but same effect, any sugestions


    1 year ago

    hello and thank you for this project.

    i have question:

    Which servo motor do I use for wheels?

    step 2 or step 8

    Please answer


    1 reply

    Reply 1 year ago


    I am sorry for late an answer. You need to print files form step 8.

    If you got any further questions please ask.


    1 year ago

    Could you upload stp files?


    1 year ago

    Great project, great Ible. Love it!


    1 year ago

    Fantastic! Great job, and Thanks!


    1 year ago

    VERY cool.


    1 year ago

    great job , i would make it but i don't have 3D printer.

    I have everything else.

    2 replies

    Reply 1 year ago

    If that is all you need, we can print parts for you.


    Reply 1 year ago

    Thank you, do you deliver in france? And how much will it cost?


    1 year ago

    Looks Like a lot of fun!! Will build one soon!!

    1 reply

    1 year ago

    Voted. Those look like fun :)

    No way I'm making them though, no 3d printer.

    2 replies

    Reply 1 year ago

    Thank you for your vote.

    We are able to print parts for you. Contact us if you are interested.


    Reply 1 year ago

    Haha, thanks for the offer, but I'm on the busy side and have no experience with Arduino and limited with practice with circuits. Thanks for the thought!


    Reply 1 year ago

    Thank you for your comment.

    We are able to print parts for you. Contact us if you are interested.


    1 year ago

    Dope! and I didnt even help you :D