How to Build a DIY Robot Dog That Follows You Around

Building your own robot dog that can follow you around is an exciting project for anyone interested in robotics, electronics, and DIY tech projects. With the right parts, tools, and a bit of coding knowledge, you can create a fun autonomous robot puppy companion.

What You Will Need to Build a Robot Dog

Creating your own robotic dog from scratch requires some key components. Here is an overview of the main parts and tools you will need:

Robot Chassis and Motors

• Chassis frame - The base structure that houses all the components. Can be made of plastic, metal, wood, etc.

• Wheels and motors - Motorized wheels enable the robot to move around and follow you. Needing at least 2 wheels and 2 motors.

• Motor driver - Takes signals from the microcontroller and controls the motors. Popular options are the L298N Dual H-Bridge or the TB6612FNG Dual Motor Driver.

• Battery - Powers the motors and electronics. Rechargeable lithium polymer batteries are a good choice.

Microcontroller

The microcontroller acts as the robot's "brain" by processing sensor inputs and controlling the motors. Good options include:

• Arduino Nano or Uno
• Raspberry Pi Pico
• ESP32

Sensors

• Ultrasonic sensor - For collision detection and measuring distance to objects.

• Infrared or optical sensors - To detect and follow motion.

• IMU sensor - Provides motion and orientation data to help with balance and navigation.

Other Parts

• Breadboard and jumper wires - For prototyping the circuits.

• 3D printed or laser cut parts - For custom chassis, mounts, and body parts.

• Screws, nuts, brackets - For assembling the structure.

• USB cable - For programming the microcontroller.

Tools

• Soldering iron
• Pliers, screwdrivers
• Wire cutters/strippers
• Multimeter for testing

Assembling the Robot Chassis and Motors

The first steps are constructing the chassis frame and integrating the motorized wheels. Here is an overview:

1. Construct the Chassis Frame

• Design or choose a chassis shape and material. Custom cutting acrylic or wood provides flexibility.

• Make mounting points for the motors, caster wheel, and electronics.

• Assemble frame pieces with brackets and screws. Ensure sturdy construction.

2. Add Motor Bracket Plates

• Attach motor plates vertically to the chassis for holding wheel motors.

• Align precisely so wheels will point straight forward.

3. Install Motorized Wheels

• Insert motorized wheels into the motor plates. Small geared DC motors work well.

• Adjust wheel position so they are parallel and point straight ahead.

• Use set screws, clips or ties to hold wheels securely in place on motor shafts.

4. Attach Caster Wheel

• Add a front caster wheel that can swivel to improve steering.

• Make sure the wheel touches the ground and can support some of the robot's weight.

Wiring up the Electronics

With the chassis complete, the next stage is electronics integration. Follow these steps:

1. Wire Up the Motor Driver

• Solder or connect motor wires to the motor driver terminals or screw terminals.

• Note: Wire one motor to input A and the second to input B.

2. Connect the Motors to the Battery

• Solder or use connectors to attach the battery positive and negative to the motor driver power inputs.

• Caution: Pay close attention to polarity to avoid shorts!

3. Connect Sensors to the Microcontroller

• Hook up ultrasonic and infrared sensor cables to input pins on the microcontroller board.

• Refer to datasheets for each sensor to find the proper connections.

4. Connect the Motor Driver to the Microcontroller

• Use jumper wires to connect the motor driver control pins to the matching digital outputs on the microcontroller.

• This allows the microcontroller to send signals to drive the motors.

• For many motor drivers, connect PWM pins to digital PWM-capable outputs.

5. Power the Microcontroller

• Connect the microcontroller Vin pin to the same battery powering the motors.

• Some boards like the Arduino Nano need a voltage regulator in between the battery and microcontroller.

Coding the Robot Dog Behavior

Now for the software portion to make the robot dog move, sense its surroundings, and follow you around.

Set Up the Code Environment

• Install Arduino IDE or MicroPython/CircuitPython for your microcontroller.

• Initialize the board, configure pins, set up motor and sensor libraries.

Make It Move Forward and Backward

• Write functions to drive both motors forward, reverse, or turn them off.

• Call these in a loop to move forward or back. Adjust speeds to control pacing.

Add Sweeping Side-to-Side Head Motion

• Use a hobby servo to make a head that sweeps left and right.

• Generate sweeps by cycling the servo between angle limits.

• Add small pauses and variations for more realistic dog motion.

Implement Collision Detection

• Read distance data from the ultrasonic sensor in a loop.

• If distance drops below a threshold, stop and reverse motors briefly to prevent collisions.

Follow Motion Using Infrared Sensors

• Continuously read IR sensor values to detect moving objects in front of the robot.

• If more motion detected on the left, steer slightly right and vice versa to follow the target.

• Fine tune the sensitivity and steering response for smooth following.

Refine Movements with the IMU

• Use IMU accelerometer and gyroscope data to calculate tilt and orientation.

• Make small motor adjustments to balance and avoid tipping over.

• Also use IMU readings to improve steering for more controlled, straight line motion.

Assembling the Body and Appearance

To complete the robot dog build, the final steps are adding a body cover and decorative elements.

1. Design and Print the Outer Shell

• Model or sculpt a dog body outer shell that fits over the chassis.

• 3D print using flexible TPU filament to allow flexing as it moves.

2. Attach the Shell to the Chassis

• Use brackets, adhesives, or fasteners to firmly fix the shell over the frame.

• Check that the wheels and sensors are still unobstructed.

3. Add Decorative Dog Features

• Use a micro servo or servo bracket for a tail that can wag back and forth.

• Attach dog ears, eyes, collar, etc to personalize and give it more character.

• Optionally add soft fabric fur material over parts of the body.

And that covers the major steps for constructing your own autonomous DIY robot dog! With all the components integrated and programmed, you now have a fun mobile robot companion that can follow you around like a puppy. Enjoy enhancing it with more sensors and behaviors.