This Arduino-Powered Robot Is the Perfect Weekend Project

There are lots of reasons why you should build a robot in your spare time. For starters, you can learn a lot and pick up some new skills that might come in handy later. It is also a lot of fun, and the robot you build can entertain you for years to come.

If you’re looking for a good place to start, then you should definitely consider building Harish Choudhary’s little robot called Otto. This 3D-printed bipedal robot is cheap, easy to build, and as adorable as can be. With a few taps on your phone, Otto can explore your desk and keep you company.

The project centers around an accessible electronics platform that makes the robot both approachable for beginners and flexible for experimentation. At the core of the design is an Arduino Nano development board, which acts as the robot’s controller. The Nano plugs into an expansion board that simplifies the process of connecting motors and sensors, removing much of the complicated wiring that often discourages first-time robotics builders.

Movement is handled by four small TowerPro SG90 Micro Servo motors. Two servos are mounted in the torso to control the robot’s legs, while the other two sit in the feet. Working together, these motors allow Otto to walk, turn, and perform playful dance routines. Despite the simplicity of the hardware, the coordinated motion gives the little robot a big personality.

Wireless control is made possible through the HC‑05 Bluetooth Module, which links the robot to a smartphone. After pairing the device, users can control Otto using a dedicated mobile app that sends commands over Bluetooth. With simple on-screen buttons, the robot can move forward, backward, left, and right, or trigger preprogrammed behaviors such as dancing and sound effects.

An ultrasonic distance sensor can be used for obstacle detection, while a small buzzer allows Otto to chirp, beep, and react to its environment. Power comes from two 3.7-volt lithium-ion batteries connected in series, delivering roughly 7.4 volts to the system through a switch and charging socket.

The robot’s body is made entirely from 3D-printed parts, including the head, torso, legs, and feet. During assembly, the servos are first mounted securely in the torso before the legs and feet are attached. Servo wires are carefully routed through the legs and into the body to keep everything tidy. Once the electronics are installed, the entire system fits neatly inside the printed shell.

Before the robot can take its first steps, it needs a bit of software. Builders upload the control program through the Arduino IDE using code developed by Choudhary. The program defines which pins control the servos, buzzer, and Bluetooth module, ensuring everything works together smoothly.

For beginners interested in robotics, Otto is a nice introduction to electronics, programming, and mechanical design — all packed into a robot that’s hard not to smile at.