Walking Robot (B3D1) Project¶

What is this?¶

The name B3D1 may evoke memories of R2D2, but it actually stands for "Beets 3D1mension," a tribute to Beets3D, the innovative company and team behind this exciting project.

This walking crank robot serves as a practical demonstration of fundamental walking mechanism concepts through engaging hands-on experimentation. It provides an educational platform for students and teachers to investigate how various physical attributes influence robot locomotion. By altering essential components such as leg length and foot design with LEGO blocks, students can explore:

Walking speed and efficiency
Stability and balance of the robot
Various walking gaits and patterns

Grasping the principles of walking mechanisms, balance, and motion dynamics is essential for fostering a deeper understanding of robotics. For more information, please refer to the Concepts of Walking page.

Key Features:

Designed to be easily modified with interchangeable parts
Can walk forward and has the ability to turn left or right
Foot attachments can be customized using LEGO blocks, allowing for experiments with different leg lengths and foot designs
Equipped with remote control functionality to try out various walking patterns

The robot acts as a powerful educational resource, enabling learners to grasp essential mechanical principles, foundational concepts in robotics, and the intricate connections between design decisions and their impact on movement performance.

What you will learn¶

Mechanical Principles: Walking mechanisms, balance, motion dynamics
Design & Experimentation: Testing different foot designs, leg lengths, and their effects on robot movement
Electronics: Working with micro:bit, motor control, basic circuitry
Coding: Programming to control robot, and remote control
Engineering: Understanding gear systems, mechanical advantage
Problem Solving: Analyzing movement patterns, improving stability, optimizing performance
Documentation: Recording observations, comparing different configurations
Teamwork: Collaborative experimentation, sharing findings
STEM Integration: Connecting physics concepts with real-world robotics applications

What you need¶

Hardware

Item	Description	Quantity	Required/Optional
BBC micro:bit	Compact microcontroller for controlling the robot	2	Y
USB cable for programming	Cable used for programming the micro:bit (V2 is used for this project)	1	Y
Main control board	Board for connecting to micro:bit, including motor driver and battery pack	1	Y
AAA Batteries	Power source for the robot	4	Y
Geared motors (N20 DC motor)	Motors providing torque and speed for movement	2	Y
3D printed parts	Chassis and mechanical components (links to STLs)	Various	Y
Outer shell components	External casing for the robot	Various	Y
Screw M4X10	Screws for assembly	8	Y
Screw M4X5	Screws for assembly	4	Y
Screw M2	Screws for assembly	2	Y
LEGO blocks	For modifications and customization	Various	N

Software

Item	Description	Required/Optional
MakeCode for micro:bit	Web-based programming platform or using iPad app	Y
Code for main Walking Robot	Basic code to control the bot Link to code	Y
Code for remote controller	Basic code for remote control Link to code	Y
3D printing software	For customizing parts, recommended using Fusion 360	N

Tools

Item	Description	Required/Optional
Screwdriver	Tool for assembling and disassembling components	Y
Wire cutters/strippers	Tool for cutting and stripping jumper wires	Y
3D printer access	Access to a 3D printer for printing 3D models	N

How it works¶

The Design¶

Core Walking Mechanism - Motor Unit - consists of 2 geared motors that provide the necessary torque and speed for the robot's movement. These motors are strategically positioned to optimize the walking mechanism, allowing for smooth and coordinated leg movements. The geared design enhances the efficiency of power transfer, ensuring that the robot can navigate various terrains effectively.

Leg (left / right) - consists of a leg with a mechanism that simulates walking in a pendulum motion. This design allows the leg to move back and forth smoothly, mimicking how a human leg walks. The foot includes a LEGO-compatible attachment, making it easy to customize and change the foot design. This feature encourages experimentation with different shapes and sizes to see how they affect the robot's movement and balance.

Electronics - Main Board - Serves as the central hub for the robot, featuring a dedicated slot for the micro:bit unit, which acts as the brain. It integrates the motor driver and facilitates seamless connectivity to both the motors and the battery pack, ensuring efficient power distribution and control.

Micro:bit - The Micro:bit is a compact, versatile microcontroller designed for educational purposes. It features a range of sensors, buttons, and LED lights, making it an ideal choice for programming and robotics projects. In this robot, the Micro:bit acts as the brain, controlling the motors and processing inputs from the user.
Battery Cases - The battery cases are designed to securely hold the power source for the robot, ensuring that the batteries are protected and easily accessible for replacement. A well-designed battery case contributes to the overall stability of the robot by maintaining a low center of gravity, which is crucial for effective walking. Proper weight distribution helps prevent tipping and enhances the robot's balance during movement.

Outter Shell - Body- This is the main body of the walking robot, designed to house the internal components and provide structural support for the legs and head.

Head - This component serves as the robot's head, providing a visual representation and housing any necessary sensors or features for interaction. This can be customised according the learning needs.
Outer Shell - This component provides the external casing for the robot, giving a nice outlook and customise base any requirements.

Remote Control You can use another Micro:bit to control the walking pattern by pressing the A or B button. Each button corresponds to the movement of one leg; pressing a button will make the associated leg step forward. For example, let's assume the A button controls the left leg and the B button controls the right leg. When you press the A button, the left leg will step forward, and when you press the B button, the right leg will step forward. This setup allows you to manage the timing and motion of both legs, providing an opportunity to explore how "control timing" affects balance, speed, and direction during walking.

Customization Options - LEGO attachment - Foot is designed to allow any LEGO attachment to be added

Adjustable leg lengths - With the LEGO attachment, you can adjust the length of the legs by adding LEGO blocks, which will change the range of motion for each steps.
Adjustable foot shape - You can also design the any shapes to test out the different effect to walking behavior, taking consideration of balance.

Assembly Guide¶

For detailed assembly instructions, please refer to the Assembly Guide.

Lesson Plan¶

Course Objectives:¶

Understand walking mechanics (balance, torque, gait patterns).
Design and build a functional walking robot using the B3D1 kit. (optional)
Integrate coding (micro:bit) for motor control and remote operation. (optional)
Experiment with modifications to optimize performance.
Foster problem-solving through iterative testing and documentation.

Course Structure¶

Total Sessions: 10 core + 4 optional Session Duration: 40–60 minutes

Objective 1: Understand Walking Mechanics (Balance, Torque, Gait Patterns)¶

Session 1: Biomechanics Basics
Exercise: Gait Diagramming – Compare human/insect gaits using stick-figure animations.
Duration: 50 min
Aligns with: Balance, gait patterns.

For details, please go to Exercise: Gait Diagramming

Session 2: Torque & Balance
Exercise: Teeter-Totter Test – Use LEGO weights to adjust robot balance on a fulcrum.
Duration: 50 min
Aligns with: Torque, balance.

For details, please go to Exercise: Teeter-Totter Test

Objective 2: Design & Build the B3D1 Robot (Optional 🔧)¶

Session 3: Mechanical Assembly & Electronics Setup
Exercise: Gearbox Relay & Circuit Detective – Assemble gear systems in teams, focusing on torque transfer, and diagnose wiring errors (e.g., loose motor connections).
Duration: 60 min

For details, please go to Assembly Guide

Objective 3: Integrate Coding (Optional 🔧)¶

Session 4: Motor Control Basics
Exercise: Step Counter – Program the robot to walk 10 steps forward/backward.
Duration: 60 min
Session 5: Remote Control
Exercise: Maze Navigator – Code a remote to steer the robot through a simple course.
Duration: 50 min

Objective 4: Experiment with Modifications¶

Session 6: Optimization Lab
Exercise: Foot Swap Challenge – Test LEGO feet on different surfaces.
Duration: 50 min
Aligns with: Modifications, performance.
Session 7: Weight & Speed Trade-offs (optional 🔧)
Exercise: Payload Test – Add weights to the robot and measure speed reduction.
Duration: 50 min

Objective 5: Foster Problem-Solving¶

Session 8: Debugging Workshop (optional 🔧)
Exercise: Sabotage & Fix – Introduce a design flaw (e.g., misaligned legs) for teams to troubleshoot.
Duration: 60 min
Session 9: Final Project
Exercise: Robot Olympics – Optimize the robot for a custom task (e.g., uphill climb).
Duration: 60 min

Optional Pathways
- Build & Code Track (Sessions 3–6): For students building the full kit.
- Experiment-Only Track (Sessions 7–10): Use pre-built robots to focus on testing/documentation.

Flexibility Notes:
- No-Kit Option: Replace B3D1 assembly with virtual simulations (e.g., Tinkercad).
- Assessment: Use lab journals (Objective 5) to evaluate iterative problem-solving.

This structure ensures core focus on mechanics, experimentation, and problem-solving, while optional sessions let you tailor depth for different groups.