[DIY] Spider Robot(Quad Robot, Quadruped)




Posted in TechnologyArduino

Introduction: [DIY] Spider Robot(Quad Robot, Quadruped)

About: My Chinese name is 許英豪. My background is Electronic and software engineering. I have over 30 years design experience on the SmartPhone, Tablet and Digital camera. I love DIY!

If you need extra support from me, it will be better that make some suitable donation to me:

2017-03-26 update:
Share the MG90 servo version - http://www.thingiverse.com/thing:2204279

you can download it and build with MG90 servos.

2016-11-1 update:

The all new spider - https://youtu.be/bxJC_vvggIc

2016-04-01 Modify:

Correct the Battery model name and dimension.

2016-01-24 update:

Open the all of design that including the software, Sketchup, EaglePCB, https://github.com/regishsu/SpiderRobot

2015-10-11 upload the PCB layout image file.

2015-10-04 update:

Step 2: schematic pdf file - spider_2015-10-04-open-v2.pdf

Step 10: picture 1.

2015-11-19 update:

Upload the Arduino sketch file which is "special dance" included(step13). Someone who are asking about it, they are interested in it. :-)


This is my first project for the 4 legs robot and it took me about 1 year development.

It is a robot that relies on calculations to position servos and pre-programmed sequences of legs.

I'm doing this by handmade way is because of it could be fun and educational for 3D design/printing and robot control.

This is the fourth generation of my design, you can take a look here if you are interested the history.


2 more projects sharing -

Spider Robot simulator by vPython


Remote control by bluetooth


Building this project is fun, however, it should take you more time and patient to implement.

If it is a hard job to you, the product comes from Sunfounder might a good choice.


Before going to next step, please aware that the soldering tools and 3D printer will be used in this project.

Let's get start and have fun!

Step 1: Electrics Parts Preparation

Here are the parts:

1x Arduino Pro Mini

1x DC-DC(12-5v/3A output)

1x HC-06 Bluetooth module(option)

12x SG90 servo(3DOF for 4 legs)

1x 3000mhA Li battery (DC12300, 90x43x17mm)

1x 12V Jack

1x 680 Ohm 1/4 watt 5% Resistor

1x 3mm Blue LED

1x Tactile Switch

1x 5x7cm perfboard

Some male and female pin headers

Small guage wire(Solid or Stranded)

I believe that these parts are most popular and not expensive. They are just cost me about 2,000 Taiwan dollar.

Step 2: Make the Main-board


upload the PCB layout image file, you should download the zip file would be better.

You can come here for more information about PCB DIY. http://regishsu.blogspot.tw/search/label/0.SpiderR...


Refer to the schematics file, and place all components like the pictures. you can make the board as small as passable.

The main-board that the last one picture is the newest version, just for you reference.

Here are some tips while you are going to building the PCB:

1. Be sure the output voltage of DC-DC module should be 5v before mount to the perfboard.

2. The servos consume a lot of power, almost 3A in full loading condition. Please use more thick wire for "power" and ground" traces.

3. Do the "open/short" test with the multi-meter for your PCB when you finish the soldering, that is the important process.

4. Using the female pin header instead of solder the modules(Arduino, DC-DC) on the perfboard directly

5. The LED will be on while the "Switch" turns off. Why I design this way is because I would like to check the power source is ok or not when I plug in the power source like battery or something else, it is a simple way for protection..

6. While you see the LED turns on after connect the 12v battery to the board, congratulation!

Step 3: Test the Main-board

Test process:

1. Don't plug the DC-DC and Arduino Pro Mini into the main-board

2. connect the battery to the 12v-Jack of main-board

3. Check the LED, if LED turns on, that is a good start.

4. Push the POWER-Switch, the LED should be off.

4. Using the multi-meter to check all of +5V and GND pins are correct

5. Push the POWER-Switch back to turn off the power, the LED turns on

6. Plug the DC-DC and Arduino Pro Mini into the main-board

7. Push the POWER-Switch, the LED turns off, but the LED of Arduino Pro Mini turns on

Then power off, and connect a servo to the first row of Leg1 connectors of main-board(pin2 of Arduino)

upload the "servo_test" code to Arduino and you will see the servo sweeps from 0 - 180 degree.

If you are here without any problem, that is a great progress!

servo_test source code:

Step 4: Building the Mechanical Parts - Download 3D STL Files

This step is going to build the robot mechanical parts, you can print the parts by yourself or ask someone who has 3D printer to help you.

I also open the 3D model design which is design by Sketchup Make version and you can modify it with your great idea.

Download the STL file from http://www.thingiverse.com/thing:1009659

Print parts list:
1x body_d.stl

1x body_u.stl

2x coxa_l.stl

2x coxa_r.stl

2x tibia_l.stl

2x tibia_r.stl

4x femur_1.stl

8x s_hold.stl

Step 5: 3D Objects Printing

And print them out by your 3D printer.

Please check the configuration of 3D printer before start to print because of it will take a long time about 7~8 hours to print them all. Be patient~~~~

There are my print setting:

- The fill density - 15%

- Nozzle - 0.3mm

- Print speed - 65

you can print these parts separate by color group.

Step 6: Preparing to Assemable

tear down the parts and check the objects printing quality, and using the sandpaper to polish the surface to make it looks good.

Refer to here to get more information: http://regishsu.blogspot.tw/2015/07/robot-quadruped-robot-re-design-3-round.html

Step 7: Assemble the Body

Put the battery between the upper body case and lower body case with 4 screws(M3x25mm)

Step 8: Assemble the Leg

And, install all of servos with legs parts, one leg comes with 3 servos and 4 screws(M1.6x3mm, or glue it anyway)

Notes: 1. Connect to all parts with screws and servos, but do not install the servo rocker arm in this step 2. Be sure the leg direction, refer to the picture 1 Refer to here to get more information:http://regishsu.blogspot.tw/2015/07/robot-quadrupe...

Step 9: Integrate 4 Legs to Body

connect all of legs to the body, and check all servos and joints are move smoothly.

Step 10: Connect Servos to the Main-board


update the picture1 which is wrong pin assignment.


Place the main-board onto the body-case and use the polymer clay to fix it.

And then, refer to the picture, follow the pin number which mark by pink color to connect all servo wire to the main-board, and green color is present the signal direction of servo wire, yellow connect to "S", red to "+", brown to "-".

Be sure the servo of legs should match the pin number of main-board and leg direction, otherwise, the legs will get crazy...

Step 11: Locate the Initial Position for Legs

This is an important procedure, the install procedure:

1. upload the "legs_init" code to Arduino to activate the servos

2. place the legs as the position shows the picture 1, and install the servo rocker arm with screws.

3. tighten all of the screw

legs_init source code:

Step 12: Organize the Wires

Then, organize the wires of the servos to make it great looking.

Now, all of hardware installation was finished.

Step 13: It Is Showtime!!

It is excited to go this step.

Let's upload the "spider_open_v1" code to Arduino to make it moves!

Please download and install the lib FlexiTimer2 first before do compile the code, http://playground.arduino.cc/Main/FlexiTimer2

you will see the action as following

1. stand up, wait 2 sec

2. step forward 5 steps, wait 2 sec

3. backward 5 steps, wait 2 sec

4. turn right, wait 2 sec

5. turn left, wait 2 sec

6. wave the hand,, wait 2 sec

7. shake the hand, wait 2 sec

8. sit down, wait 2 sec

9. back to 1


PS. the spider_open_v3 is add an interesting movement of "body dancing"

spider_open_v1 source code:

Step 14: Do Something Special

you can add more special feature like change the move speed dynamically with remote control, that will let your robot more attractive.

If you find my design interesting, you could make a small donation:

Welcome to share the funny gaits or movement.

The remote control


Here are some idea share with you in my blog.



Add the IR-detector to detect the obstacle.



handmade the PCB



29 People Made This Project!


  • Make it Move Contest

    Make it Move Contest
  • Casting Contest

    Casting Contest
  • Microcontroller Contest

    Microcontroller Contest

We have a be nice policy.
Please be positive and constructive.


5 Questions

can i use arduino mega 2560?

the board of 2560 is too big for the robot body.
it may not a good choise.

Hello, please, how is the right pin assignment


hi ,I like your robot design very much but I want to make hexapod so if you can help me, please make the body design for placenment of 6 legs . I had made hexapod using ruler but it is not that much effective and accurate so by using your robot design I want to upgrame mine robot if you help me sir


can i use nano shield and nano r3? for replace the mainboard..

The guy who made this pirated it from a company called sunsun. I built this two years ago and posted loads of upgrades an mods to the code..the guys deleted ALL my posts haha. Gonna create my own instructable with BETTER CODE AND INSTRUCTIONS AND BODY STLS. GUYS A MUPPET

can i use a breadboard?


if anyone else is having trouble with the battery size, I made a customizable thingiverse page to generate just the body (top and bottom) with input for the battery dimensions. Check it out at:


any feedback is welcome, thanks

2 replies

Hello, first I want to say thanks to you to build the customized body. I try to create a body for my lipo battery this morning. But the system showed the error code like this. Do you know how to fix it?

#<RuntimeError: Failed to get https://www.thingiverse.com/download:4517698 403: Forbidden>

Sorry I did not answer earlier. There was a minor bug - a missing font -
that was fixed. It should work now, except the thingiverse customizer
is broken - for all customized things, it has been that way for over a week.

Could you give me the pin number that corresponds to each servo and the ultrasonic sensor, and the bluetooth one. I would appreciate it because I am new to this but I am learning. Thank you.

Could you give me the pin number that corresponds to each servo and the ultrasonic sensor, and the bluetooth one. I would appreciate it because I am new to this but I am learning. Thank you.

Hello can someone help me
all servo turns wrong.
can one change this in the program?


Добрый день , большое спасибо Вам за столь подробный материал!

Он очень сильно помогает в изучении данной тематики, но я безумно нуждаюсь в ваших пояснениях, если вам не трудно прошу Вас пояснить вот этот расчет :

//temp length

const float temp_a = sqrt(pow(2 * x_default + length_side, 2) + pow(y_step, 2));

const float temp_b = 2 * (y_start + y_step) + length_side;

const float temp_c = sqrt(pow(2 * x_default + length_side, 2) + pow(2 * y_start + y_step + length_side, 2));

const float temp_alpha = acos((pow(temp_a, 2) + pow(temp_b, 2) - pow(temp_c, 2)) / 2 / temp_a / temp_b);

Если вас не затруднит начертите как и что вы считаете, это очень поможет , моя электронная почта ty545545545@gmail.com.

Заранее большое спасибо.

I love the way this turned out! It looks like a creepy mecha droid :)

I can't find the code for the IR detector version ? (maybe i'm blind today). I'm not really familiar with arduino, and i want to use ultrasonic detectors. I don't know if someone should help me wit this project.

Thanks. Bye !

If you need it, you can call me because I send the program to have a look at what I did.