Introduction: 3D Printed Robot

Picture of 3D Printed Robot

The nice thing about 3D printing is that it makes building robots easy. You can design whatever configuration of parts that you can dream up and have them in your hand virtually right away. This allows for rapid prototyping and experimention. This particular 3D printed robot is an example of that.

This idea to have a walker bot that shifted its front center of balance is one that I have had for a few years. However, implementing it with off the shelf parts always proved rather tricky and prevented me from really trying. Yet, when I realized that this could be done quickly and easily with 3D printing, I was able to finally create this robot in about two days. Basically, 3D printing had enabled me to take an idea and actualize it in less than 48 hours.

If you want to try your hand at making this easy robot, I have included the files and posted instructions for you to make on yourself. This is definately a fun weekend project for someone with a 3D printer who knows a little bit about electronics and soldering to get their feet wet with robotics.

Step 1: Robot Parts

Picture of Robot Parts

Get the following materials:

(x1) Afinia 3D printer (RadioShack #277-224)
(x2) Standard servos (RadioShack #273-766)
(x1) Arduino micro (RadioShack #276-258)
(x1) 40-pin socket (RadioShack #276-1996)
(x1) PCB (RadioShack #276-150)
(x1) 9V battery snap (RadioShack #270-324)
(x1) 9V battery holder (RadioShack #270-326)
(x1) 9V battery (RadioShack #23-2209)
(x2) 3-pin headers (RadioShack #276-266)
(x13) M3 nuts and bolts
(x4) pencils

Step 2: 3D Print Parts

Picture of 3D Print Parts

3D print the attached files using your particular 3D printer. You may need to setup the files to work with support for your particular setup.

Step 3: Front Assesmbly

Picture of Front Assesmbly

Insert four bolts into the front of the robot.

Slide the two front leg gears into the compartment in the front of the robot body such that the leg sockets are pointed outwards.

Place the gear inbetween the two rack gears of the legs.

Press the servo's drive shat into the socket on the center gear and use a screw to fasten this into place.

Finally, bolt the servo in place using the bolts installed earlier to complete the front assesmbly.

Step 4: Bottom Servo

Picture of Bottom Servo

Slide the bottom servo into its mounting bracket and bolt it into place.

Step 5: Attach the Torso

Picture of Attach the Torso

Press fit the 3D printed torso centered upon the motor's drive shift and bolt it into place.

Step 6: Insert Pencils

Picture of Insert Pencils

Insert pencils into the torso socket such that the eraser ends are sticking out.

Step 7: Pull the Erasers

Picture of Pull the Erasers

Pull the erasers off of two pencil using a pair of pliers.

Step 8: Insert More Pencils

Picture of Insert More Pencils

Insert the end of the pencils that the eraser used to be attached to into each of the front leg sockets.

Step 9: Build the Circuit

Picture of Build the Circuit

Solder the 40-pin socket to the center of the board.

Connect the black wire from the 9V battery snap to the ground pin on the Arduino socket and the red wire to the V-in pin.

Solder the first three pin male header to the 40 pin socket as follows:

header pin 1 ---> 5V power
header pin 2 ---> Ground
header pin 3 ---> Digital Pin 8 (socket pin 36)

Solder the second three pin male header to the 40 pin socket as follows:

header pin 1 ---> 5V power
header pin 2 ---> Ground
header pin 3 ---> Digital Pin 9 (socket pin 37)

Step 10: Drill

Picture of Drill

Drill a 1/8" hole centered upon a part of the circuit board where there are no soldered electrical connections.

Step 11: Insert the Arduino Micro

Picture of Insert the Arduino Micro

Insert the Arduino micro into the appropriate pins on the socket.

Step 12: Attach the Battery Clip

Picture of Attach the Battery Clip

Attach the battery clip to the bottom of the circuit board while being careful not to short circuit any electrical connections with it.

Step 13: Attach the Circuit Board

Picture of Attach the Circuit Board

Bolt the circuit board to the mounting holes on the robot body.

Step 14: Wire the Servos

Picture of Wire the Servos

Plug the servo sockets into the appropriate male header pins on the circuit board.

Step 15: Program the Arduino

Picture of Program the Arduino

Program the Arduino with the following code:

// Code for a 3D Printed Robot
// Learn more at:
// This code is in the Public Domain

//add the servo library
#include <Servo.h> 

//Create two servo instances 
Servo myservo; 
Servo myservo1; 
//Change this numbers until the servos are centered!!!!
//In theory 90 is perfect center, but it is usually higher or lower.
int FrontBalanced = 75;
int BackCentered = 100;

//Variables to compensate for the back center of balance when the front shifts
int backRight = BackCentered - 20;
int backLeft = BackCentered + 20;

//Setup initial conditions of the Servos and wait 2 seconds
void setup() 

void loop() 
  //Walk straight
  for(int walk = 10 ; walk >= 0; walk -=1) { 
  //Turn right
  for(int walk = 10 ; walk >= 0; walk -=1) { 
  //Walk straight   
  for(int walk = 10 ; walk >= 0; walk -=1) { 
  //Turn left  
  for(int walk = 10 ; walk >= 0; walk -=1) { 


//Walking function
void walkOn(){
    myservo.write(BackCentered + 30);
    myservo.write(BackCentered - 30);

//Turn left function
void goLeft(){
  BackCentered = backLeft;
  myservo1.write(FrontBalanced + 40);       

//Turn right function
void goRight(){
  BackCentered = backRight;
  myservo1.write(FrontBalanced - 40);              

//Go straight function
void goStraight(){
  BackCentered = 100;

Step 16: Plug in the Battery

Picture of Plug in the Battery

Plug in the 9V battery and secure it in place with the battery clip.


BlueOrchids (author)2017-10-15

I love this project but I can't seem to get the code working on the bot. I have it all built but nothing happens once I plug in the Arduino to the circuit.

Does anyone have pictures with the finished circuit that could post pictures of the front and back??

jcarolinares made it! (author)2017-08-08

Thank you so much for this incredible design

I created a version adapted for Futaba motors and Arduino UNO boards.

In my case I used an open source FPGA, an Icezum Alhambra board:

+Info of the redesigned version here:

PD: The googly eyes improves the design a lot ^^

lonelyBlobby (author)2017-07-23

Is this possible with Rpi

randofo (author)lonelyBlobby2017-07-23

If you redesign it to accommodate one, sure. I don't see why not. However, this version is designed for the Arduino Micro.

gaurav. (author)2017-07-01

Can I make it with arduino nano?

Will there be any problem if I use it with nano........

alexbuiltit (author)2016-10-04

Im wondering if I have to scale the stl before printing it to account for 3D printing shrinkage?


DavonM (author)2016-06-02

where's the code at?

генак made it! (author)2016-03-16

I have made the robot, following Randy instructions given here. Problems I have had was that I am new to Arduino, and instead of "Micro" I bought "Mini". That didn't work so well, so I bought "Uno", as I saw one guy on internet doing nicely with servos on it. And also the body I didn't print, as that would take 20 hours, but cut out of styrofoam. Tried to be economical (here, in Ukraine, we have to be...)

hypers (author)2016-02-12

Ok. Where's the video of the walking bot ? O_o

brittanyclearview (author)2015-05-29

Do you know what else would work in place of the 3-pin header & extension cable? It is not available at RadioShack anymore....

you can buy a breakable pin header that's what i did and it worked perfectly fine you just have to break it so there is 3 i bought mine at amazon

SirTeddyI (author)2015-06-28

Do you remember the total cost? For parts, not the 3D printer, of course.

mol4u (author)2015-02-02

I found the code and am looking at it. What servo library and code do I use? The #include line seems to be blank.

MikeM15 (author)2014-12-09

I have a student building this and the parts print just fine after some minor adjustments on the placement (we have a MakerBot). For those having trouble downloading the files: right click the link and choose Save Target As... (or whatever the phrase is for your browser) and make sure you name the file appropriately. For example, using "3dRobotTorso.stl" as a file name instead of whatever your browser wants to use makes things easier when you then need to find and open it in your printing software. Dunno why the Instructables server is messing with the file type, but at least we have our built-in workaround.

vkillmore (author)2014-12-08

Trying to down load these parts but I keep getting gibberish any ideas? Body and one arm download perfectly the others I am unable to download

kdewitt (author)2014-11-21

I would like to download the STL files as well, but when I click them they open in the browser and there is no way to save them in the appropriate format. Please make them available. I would like to make this for my son. Thanks.

Elflin (author)2014-11-09

Hi! I really want to have a go at making this, but i think that the links for the two front leg STL files are broken, so I can't download them. Could you please replace those links? Thanks!

wavelet_spaghetti (author)2014-10-27

adorable! I want ten of these in different colors. they can do all the erasing in my writing for me

chyy0906diy (author)2014-10-26


SparkySolar (author)2014-10-24

Thank you for your nice instructable.


randofo (author)SparkySolar2014-10-24

You're welcome.

janakarathinam (author)2014-10-24

I want to have a 3D printer just for making this robot. It's awesome Randy!

randofo (author)janakarathinam2014-10-24


janakarathinam (author)2014-10-24

Hi, olt the servo in place using the bolts installed earlier to complete the front assesmbly.

M.C. Langer (author)2014-10-23

I want to have a 3D printer just for making this robot. It's awesome Randy!


Greetings from Azerbaijan!

randofo (author)M.C. Langer2014-10-23

Nada mas lo importante.

How is life in Azerbaijan? Build any robots of your own recently?

You are welcome to come use the 3D printers here any time.

M.C. Langer (author)randofo2014-10-23

Well, I build these three instructables in Baku:

Life in Baku? Married to the most amazing woman, trying to get a job (it's very complicated if you don't know at least Azerbaijani and Russian), with two cats (Cringer and Leeloo. You can see them in action in the Superheroic Wrist Gun video). But everything is ok.

And thanks for the invitation! Remember you have a home here in Baku, the day you want to come and visit!

electro18 (author)2014-10-23

That's awesome ! :)

About This Instructable




Bio: My name is Randy and I founded the Instructables Design Studio. I'm also the author of the books 'Simple Bots,' and '62 Projects to ... More »
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