BAbout this program
Otto DIY — Bipedal Walker Robot
Otto is one of the most beloved open-source DIY robots: a small bipedal walker that anyone can build with a 3D printer, an Arduino Nano, and four micro servos. Originally created by the Otto DIY community, Otto can walk, turn, dance, sing, and emote with optional ultrasonic, sound, and LED matrix add-ons.
This Program is a learning interface for the Otto DIY platform. Full hardware control runs on the Arduino firmware in the source repo below. The orobot.io control sandbox lets you experiment with the command surface (walk, turn, jump, gestures, songs) before wiring it into your own Otto.
Specs
| Property | Value |
|---|---|
| Type | Bipedal walker |
| Servos | 4 × SG90 micro servo (LeftLeg, RightLeg, LeftFoot, RightFoot) |
| Controller | Arduino Nano (also Uno, Micro, Mega, ESP8266, ESP32 in dev) |
| Height | ~12 cm |
| Estimated cost | $30–50 USD |
| Estimated build time | 2–6 hours |
| Skill level | Beginner / Intermediate |
Bill of Materials (typical Otto build)
| Item | Qty | Notes |
|---|---|---|
| Arduino Nano | 1 | ATmega328P, USB-B Mini |
| SG90 micro servo (180°) | 4 | LeftLeg, RightLeg, LeftFoot, RightFoot |
| HC-SR04 ultrasonic sensor | 1 | optional, eyes / obstacle avoidance |
| Active piezo buzzer | 1 | sounds + songs |
| 4× AA battery holder + batteries | 1 | or 1S/2S LiPo with regulator |
| Jumper wires + perfboard / Otto shield | 1 set | |
| 3D-printed body parts (head, body, legs ×2, feet ×2) | 1 set | STLs at ottodiy.com |
| M2 / M3 self-tapping screws | ~10 |
Source
- Repo: https://github.com/OttoDIY/OttoDIYLib (canonical Arduino library, v13.0)
- STLs + assembly guide: https://www.ottodiy.com/
- Author: Otto DIY community
- License: GPL v3 (code) + CC-BY-SA 4.0 (mechanical design)
Hardware integration status
Otto runs on Arduino Nano with the OttoDIYLib firmware. orobot-firmware does not yet have Arduino Nano support — this Program provides the learning interface and command surface. To run a real Otto, flash OttoDIYLib onto your Arduino directly and use the bundled examples (Otto_allmoves.ino, Otto_APP.ino).
Available commands
- home — return to neutral standing position
- walk(steps, time, dir) — bipedal walk forward (
dir=1) or backward (dir=-1) - turn(steps, time, dir) — turn in place
- jump(steps, time) — quick crouch + extend
- moonwalk(steps, time, h, dir) — Otto's signature dance move
- gesture(name) — Happy, Sad, Angry, Love, Confused, Wave, Magic, Fail, Sleeping, etc.
- sing(song) — 19 built-in tunes (S_happy, S_sad, S_surprise, ...)
Credits
Massive thanks to @JavierIH, @Obijuan, @sfranzyshen, and the dozens of contributors who have built and maintained Otto DIY for nearly a decade. Otto is one of the projects that proved tiny, friendly, accessible robots could be a global open-hardware movement.
🖨 Print Files (4)
OttoDIY_Leg_V9.stl
OttoDIY_body_V9.stl
OttoDIY_foot_V9.stl
OttoDIY_head_V9.stl
Required Hardware
| Item | Qty | Unit Cost (USD) | Total (USD) | Notes |
|---|---|---|---|---|
| Arduino Nano (or compatible — Uno/Micro/ESP32) | 1 | $10 | $10 | Brain — Amazon search |
| Arduino Nano I/O Expansion Shield | 1 | $7 | $7 | Adds proper 3-pin servo headers; no soldering — Amazon search |
| SG90 Micro Servo (9 g, 180°) | 4 | $4 | $16 | Hips & feet — Amazon search |
| HC-SR04 Ultrasonic Distance Sensor | 1 | $4 | $4 | Obstacle avoidance — Amazon search |
| Active 5V piezo buzzer | 1 | $2 | $2 | Sound effects / music — Amazon search |
| 4× AA battery holder with on/off switch + leads | 1 | $5 | $5 | Power — Amazon search |
| AA alkaline batteries (4-pack) | 1 | $5 | $5 | First fill — Amazon search |
| Female-to-female Dupont jumper wires (40-pack) | 1 | $5 | $5 | All wiring — Amazon search |
| USB-A to Mini-USB cable | 1 | $5 | $5 | Programming — Amazon search |
| HC-05 / HC-06 Bluetooth module (optional) | 1 | $8 | $8 | Mobile-app control — Amazon search |
| 8×8 LED matrix (MAX7219) (optional) | 1 | $6 | $6 | Animated mouth — Amazon search |
| Photoresistor / LDR module (optional) | 1 | $3 | $3 | Light sensing — Amazon search |
| Capacitive touch button (TTP223) (optional) | 1 | $3 | $3 | Pet/touch interaction — Amazon search |
| 3D-printer filament (PLA, 1 spool, ~115 g used) | 1 | $20 | $20 | All printed body parts — Amazon search |
| Small Phillips screwdriver set | 1 | $8 | $8 | Servo horns + chassis screws — Amazon search |
Estimated total: $50–$75 USD (core parts only) / $80–$110 USD (with all optional sensors). Source: https://github.com/OttoDIY/OttoDIYLib and https://www.ottodiy.com/.