Introduction: HUNGRY ROBOT - Coin Eating Robot! (3D PRINTER, ARDUINO, SENSOR, SERVO)

About: Hi, I'm Eunchan Park from S.Korea. I have 3 missions Making Happy Things, Sharing How To Make Happy Things, Copying Happy Things Maker for the world's Happiness In order to pursue my mission, I have a big go...

I really love to make use-for-nothing robots such as Drinky (Drinking buddy robot). I want to make a robot for emotional purpose not for functional. This is fun, makes smile and feels good.

This robot is also one of useless robot but, I'd like to make a funny robot! There are many coin-eating robots (Robie). I'm going to make it by using 3d printer and an Arduino. All source code and 3d printing modeling files are opensource. Feel free to make it by yourselves.



Install Arduino IDE

Install CH340 Driver (for Chinese version)

DOWNLOAD - source code

Select board / Processor / Com port

  • Select Arduino Nano ATmega328P (Old Bootloader)

plug your arduino nano

find / select emerging com port

Hit the upload button


Download 3d modeling files from Thingiverse

Print all parts one by one

  • Brim setting needs at least 1 mm


In this circuit, all parts are connected with Female - Female Dupont Cable. In order to save space in the robot, we need to cut and re-wire manually.

A servo motor uses 3 pins. Vcc and GND is essential. A PWM pin must be allocated with the servo motor. In this project, pin 13 is used.

The sensor is an infrared sensor. The sensor uses 3 wires as well. In order to read distance from an object, the arduino neeeds to read an analog input. In this project, A7 pin is allocated.

Step 5: Prepare F-F Cable and the Sensor

In this circuit, all parts are connected with female-female Dupont cable.

Step 6: Cut the Wire

in order to save space in the robot we need to cut and rewire manually.

This sensor is an infrared sensor The sensor uses three wires.

in order to read distance from an object, the Arduino needs to read analog signal from this sensor.

we are going to use pin A7 for obtaining the sensor value

Step 7: Strip the Cable End by Using a Stripper

Step 8: Twist Wires and Finish With the Tape

Step 9: Wiring the Servo Motor

A servo motor uses three pins. VCC ground and PWM.

A pwm pin from the Arduino must be allocated with the servo motor. In this project we are going to use pin 13.

Step 10: Making Arms

The black one is a horn from servo motor. We need to use the screwdriver and screw bolt.

Step 11: Put the Small Part Behind of the Motor

Step 12: Put the Motor Inside of the Body

and fix the motor with the body.

Step 13: Put the Sensor Into the Body and Make Sure the Direction

Step 14: Assemble the Basket Part

Step 15: Put the Part in Front of the Body

Use the cable tie from inside to outside.

Step 16: Put the Cable Tie Through the Hole.

Step 17: Use One More Cable Tie.

cut the rest of cable tie. it's very simple you don't need to use bolt anymore.

Step 18: The Head Part

I'm gonna assemble the head part in the same way.

Put the cable tie through the hole and use one more cable tie.

Check the head moves well. Cut the rest of them

Step 19: Assemble the Link Part

This part is most important part. This is a link and it links from head to body. Assemble them together in same way. Try some move

Step 20: Connecting the Wires

Make sure the color, location and pin numbers

Step 21: Connect Them on the Arduino

make sure the colors

Step 22: Put the Arduino in the Body and Plug the USB Cable

And then, assemble the cover

Step 23: Attaching the Eye Balls

I used Blu Tack

Step 24: DONE!!!

This is full - long - take video (*just in case)



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    10 Discussions

    I saw this little robot live at Maker Faire Berlin. This Idea is just awesome :-)

    Thanks for sharing this well documented Instructable!

    1 reply

    Thank you Vulcaman! I hope see you in the next Makerfaire again!

    I love it and your instructions are great

    I hope to make it after I finish my current project

    1 reply

    Thanks @SallyP11
    Please feel free to leave any comment or questions. Even though I wrote this instruction as detail as possible , there could be some ambiguous things. I'd like to help you :)


    4 months ago

    Nice. Very well documented! Interesting idea.

    1 reply

    Thanks rgpfx! If you have any question, please feel free. :)


    5 months ago

    This is awesome! Thanks for sharing I really like it :)

    1 reply

    Thanks ledmod, I am happy to hear it. if you have any question, please let me know ;)