Otto B.O.T. - Battery Operated Titan

Otto B.O.T. – Battery Operated Titan, a compact Humanoid Ninja.

This is a modified version of the Otto Ninja, created for the HP Otto Challenge. The model is engineered to work seamlessly with the official HP Otto circuit board, eliminating the need for custom electronics.

See Otto B.O.T. in action!

In this video, you can see the compact humanoid version moving and using its arm servos. Notice the LED Eyes module in action

While fully compatible with the original Otto Ninja, this version features several key enhancements. It utilizes six servo motors: two 360° continuous rotation servos for the feet, two 180° servos for the legs, and two additional 180° servos for arm movement. Key upgrades include a redesigned Top Lid and an integrated LED Eyes module.

Otto B.O.T. was designed with modularity in mind; individual parts can be printed and retrofitted onto existing builds. For instance, the arm modules can be added to the Otto Ninja Humanoid.

If you own the standard (small) Otto Ninja, simply printing the modified top cover allows you to mount arm servos and upgrade to a Humanoid version while maintaining the original, smaller footprint.

The design also offers aesthetic and functional flexibility. Decorative armor elements, specifically shaped to match the chamfered edges of the Otto body, are available and can be retrofitted onto any Otto robot you already own.

Furthermore, the ultrasonic sensor can be replaced with 5 mm LEDs using the LED Eyes module for a custom look.

Chassis & Electronics Options

The model is designed to be versatile, offering two distinct assembly paths depending on your hardware:

• BASE: Use this element if you are building the robot with the official HP Otto circuit board. It is perfectly tailored to fit the HP PCB securely.

• BASE-standard: Use these element if you prefer to use standard electronics (such as an Arduino Nano with a Shield or an ESP32).

This dual-option design ensures that Otto B.O.T. is accessible to everyone, whether you are part of the HP Challenge or building a custom project from scratch.

What You’ll Need (BOM)

To build the Otto B.O.T. you can choose between two hardware paths:

• Electronics (HP Edition):

  • 1 x HP Otto Circuit Board (Official PCB)

  • 1 x Compatible Battery pack

• Electronics (Standard DIY Edition - using BASE-standard):

  • 1 x Arduino Nano with Shield OR ESP32

  • 1 x Buzzer module (integrated mounting point in the base)

  • 1 x Toggle switch (dedicated slot in the base)

  • 1 x Compatible Li-Po or AA battery pack

• Common Components:

  • 4 x 180° Micro Servos (for legs and arms)

  • 2 x 360° Continuous Rotation Servos (for the feet)

  • 2 x O-rings (68 mm OD, 60 mm ID, 4 mm thickness) – used as tires

Sensor & Eye Options

The head design is flexible, allowing you to choose the "look" and functionality of your robot:

• LED Eyes Module: Use this for a stylized look with two 5 mm LEDs.

• Ultrasonic Sensor (HC-SR04): If you prefer classic obstacle avoidance, the head remains fully compatible with the standard HC-SR04 ultrasonic sensor instead of the LED module.

Recommended Print Settings

• Recommended using an FDM 3D printer.

• Layer height: 0.2 mm (for best detail and fit)

• Infill: 15% 

• Walls: Minimum 3

• Material: PLA

I am also currently developing a remote controller for Otto robots (Work in Progress), designed to make interaction much more intuitive. This upcoming project features dynamic button labeling for assigned functions, controlling multiple robots and allows for real-time servo trimming directly from the controller, eliminating the need for constant reprogramming. You can find more information and follow the development on my GitHub page: https://github.com/boryspimpek/FusionPad32000.git