DIY Robot Bunny: How to Build Your Own Robotic Rabbit at Home

Choosing Your Build Framework: Cardboard vs. 3D Printing

The Rapid Prototyping Approach: Cardboard

The Professional Route: 3D Printing

Which path do you take?

Essential Hardware Components and Tool Checklist

The Brains: Choosing Your Microcontroller

The Actuators: Servos and Motors

• Position servo motors (180° rotation): Drive ear tilt and head rotation with precise angle control. Standard SG90 servos are affordable and widely compatible.
• DC gear motors: Power wheeled or leg-based locomotion for a mobile build.

Sensors and Feedback

• Photoresistors (light sensors): Detect ambient light changes to simulate a "pettable" touch response when a hand covers the bunny's back.
• Single or tri-color LEDs: Create glowing robotic eyes with minimal wiring overhead.

Power and Safety Assembly

Step-by-Step Mechanical Assembly of the Rabbit Chassis

Step 1: Fabricating the Core Cavity

What to Do

1. Print or trace your chosen chassis template onto corrugated cardboard or lay out your 3D-printed shell pieces.
2. Pre-fold all scored fold lines before applying any glue. Cold-folding first reduces tearing and keeps the wall angles crisp.
3. Take a sharp blade and slice out small openings for your motor parts and cables. Use a ruler to align it so that your cuts stay straight.
4. One piece at a time, attach the main box together using hot glue or regular craft glue. Hold each edge for a full minute to dry before moving on.

Critical tip: Do not pinch or compress the interior alignment walls while the glue sets. Distorted walls will throw off servo mounting angles.

Step 2: Mounting the Actuators

Servo Mounting Checklist

Step 3: Whiskers, LED Eyes, and Wire Routing

LED Eye Installation

• Poke or drill two tiny holes right on the front of the head space, matching the size of your 5 mm LEDs.
• Push the long metal legs of each light through from the outside so the plastic bulb sits flat against the face.
• Route both wire pairs upward along the interior wall toward the center-top compartment where your microcontroller sits.

Whisker Attachment

• Cut four to six lengths of stiff craft wire or nylon monofilament, approximately 8-10 cm each.
• Insert pairs symmetrically through pre-punched holes on each side of the nose area.
• Secure with a small dot of hot glue on the interior side. Do not block adjacent wire channels.

Wire Management Rules

Wiring the Circuitry and Sensor Integration

Insulating the Circuitry

Wiring the Touch Interface

• VCC to 3.3V pin
• GND to ground pin
• Signal out to any available analog input pin (e.g., P0)

Common Setup Failure Point

Coding Your Bunny: Logic, Movements, and Interaction Codes

The "Idle" Loop

• Pulse the LED eyes on a 2-second fade cycle (simulate breathing)
• Trigger a minor ear twitch every 8-12 seconds using a randomized interval
• Keep motor output at zero unless an event fires

The "Petted" Event

1. Read analog pin value every 100 ms
2. If value falls below threshold, enter "petted" state
3. Sweep both servos from 90° to 130° and back (ear wiggle)
4. Step DC motors forward for 500 ms
5. Return to idle loop

Sample Script Template: Arduino (C++)

// Pin assignments
#define LIGHT_SENSOR A0   // Photoresistor signal pin
#define LEFT_EAR     9    // Servo PWM pin
#define RIGHT_EAR    10   // Servo PWM pin
#define LED_EYE      6    // LED PWM pin (supports analogWrite)
#define MOTOR_FWD    5    // DC motor forward pin

#include <Servo.h>
Servo leftEar, rightEar;

void setup() {
  leftEar.attach(LEFT_EAR);
  rightEar.attach(RIGHT_EAR);
  pinMode(LED_EYE, OUTPUT);
  pinMode(MOTOR_FWD, OUTPUT);
}

void loop() {
  int light = analogRead(LIGHT_SENSOR);

  // Idle: pulse LED eyes
  analogWrite(LED_EYE, (millis() / 10) % 255);

  // Petted event trigger
  if (light < 300) {
    // Ear wiggle
    leftEar.write(130); rightEar.write(130);
    delay(300);
    leftEar.write(90);  rightEar.write(90);
    // Forward step
    digitalWrite(MOTOR_FWD, HIGH);
    delay(500);
    digitalWrite(MOTOR_FWD, LOW);
  }
}