Introduction: LittleBot 3D Printed Arduino Mobile Robot

About: At LittleBots we are creating 3D Printed Robot Kits that get Kids excited about robotics and STEM

The LittleBot robotics kit was created to be a simple introduction to robotics. It shows all the necessary components of robotics, sensing, decision-making, and articulation all in a nice, easy to assemble package.

The LittleBot is fully 3D printed, which allows it to be assembled with only 3 screws (7 if you are being over-zealous). It is also controlled by and Arduino Nano, to take advantage of the global community around that. The LittleBot has several modes normally, including wander, remote-control (with android app), line follow, and wall follow. Code for all of these are available on the downloads page of the LittleBots website. LittleBot was fully funded on Kickstarter in the middle of 2017 and recently completed deliveries. The kits are now available on the LittleBots website. All of the 3D printing files for the LittleBot are available on Thingiverse. The Arduino Code is on the LittleBots download page. This tutorial is fairly short. We are only posting the assembly Video and the Wiring Diagram for the LittleBot. We will post a detailed, step-by-step very soon. But we wanted this resource to be available. What you need.

  • 2x Continuous Rotation Servos
  • 1x Meped/LittleBot PCB
  • 1x Arduino Nano
  • 1x HC-06 Bluetooth Module
  • 1x Ultrasonic Sensor
  • 1x 6v 4 AA Battery Holder

All of these supplies can be purchased on the LittleBots Website

Step 1: Secure Servos in Base

  1. Insert the two continuous rotation servos into the base so that their wires feed out the back.
  2. Secure with a single servo screw on the armature side of the servo. (you may use 2 screws, but they are not necessary)

Note: To help to get the wire started through the back hole you might use needle-nosed pliers rather than fingers

Step 2: Attach Wheels

  1. Insert the servo horn into the slot on each wheel. (Make sure that it is well seated)
  2. Press the wheel onto the servo armature
  3. Secure the wheel with the horn screw

Step 3: Attach Swivel

Hot-glue the swivel piece to the center-rear of the base.

Step 4: Assemble Gripper

The Littlebot gripper can be assembled by following these instructions. The above photos are for reference.

Step 5: Attach Gripper to Shell

  1. Attach the finished gripper to the shell of the Littlebot by sliding it over the mounting nubs.
  2. Feed the servo wire through the side slot.

Step 6: Prepare Bluetooth Module

To fit into the Littlebot the bluetooth module has to lay nearly flat against the PCB board. Use a pair of needle-nosed pliers to bend the leads. Be careful not to break them off.

Step 7: Prep the Ultrasonic Sensor

  1. Use 4 male-to-female jumper wires to connect the ultrasonic sensor to the Meped Board. Make sure that the wires connect to the same labeled locations on the sensor and and the board

Step 8: Insert Ultrasonic Sensor Into Head

Press the ultrasonic sensor into the eye holes of the head.

Step 9: Connect the Electronics

Use the wiring diagram to attach the servo and ultrasonic sensor.

Step 10: Insert Electronics

  1. Slide the board into the slots at the back of the base.You can secure the board with a servo mounting screw in the upper-righthand corner of the board if you want to.
  2. Once you have secured the board. Plug in the Bluetooth module

Step 11: Insert Battery Pack

Insert the battery pack into the slot in the center of the base.

Step 12: Seal It All Up.

Thread the battery lead through the top of the head and press the shell onto the base until it snaps into place.

And you are done assembling the LittleBot. Enjoy.

Step 13: Other Things

Program the LittleBot

The Littlebot code can be downloaded from the LittleBots website. Grab the latest version of Walter_OS.ino and the Android app for best results.


  1. Do not try to upload to the arduino when the bluetooth is connected. USB and Bluetooth cancel each other.
  2. When using the app, make sure to pair the device to the LittleBot in settings first, then connect bluetooth when the app starts up, else the app may crash.

Parts and other Resources

All parts for the LittleBot that appear in the tutorial can be purchased from the LittleBots Store.