Robotics Project Hub

Learning guides / Start from the mechanism

Robotics tutorials for understanding, not memorizing

Focused guides that connect the theory to a real algorithm, circuit decision, or interactive simulator. Each one is self-contained and links to the lab where you can try it.

Browse by topic

8051 3Algorithms 6Arduino 17Autonomous Robots 1Autonomy 6Calibration 8Communication 2Computer Vision 1Control Systems 11Coordinate Frames 1Design Decisions 1Drivetrains 1Electronics 7Encoders 3ESP32 2Filtering 1Firmware 2Grasping 4Holonomic Drive 3I2C 2IMU 3Kinematics 6Lidar 1Line Following 1Mapping 1Mechanical Design 9Microcontrollers 4Middleware 1Mobile Robots 14Motion Control 1Motion Planning 1Motor Control 9Motors 6Navigation 5Obstacle Avoidance 1Odometry 5OpenCV 1Path Planning 6PID 3PID Control 1Pose Estimation 1Power 3Precision Motion 3PWM 3Raspberry Pi 1Robot Arms 6Robot Software 4ROS 2 5Sensors 19Servos 3Setup 1SLAM 1State Machines 2Stepper Motors 5Teleoperation 1TF2 1Tuning 1Ultrasonic 1Wireless 2Wiring 1

Intermediate · 25 min

Friction, Force Closure and Why Two Contacts Is a Bet

Why the object squirts out however hard you squeeze, and what the friction cone actually says.

Read tutorial

Intermediate · 35 min

A Pick-and-Place State Machine That Survives Failure

Approach, grasp, verify, lift, place — and what to do when the verify says no.

Read tutorial

Beginner · 30 min

Robot Gripper Types and How to Size Grip Force

Pick the gripper type, then size the force with the term everyone forgets: acceleration.

Read tutorial

Intermediate · 30 min

Servo Gripper Force, Stall and Why Compliance Wins

The knob is a position, the walls are forces, and stiffness is the exchange rate between them.

Read tutorial

Intermediate · 25 min

Field-Oriented Drive: Make Forward Mean Forward

Rotate the stick by minus the heading, and the robot stops arguing with the driver.

Read tutorial

Beginner · 25 min

Holonomic Drives: Omni, Mecanum, Swerve Compared

Four drivetrains, three degrees of freedom, and what each one charges you for them.

Read tutorial

Intermediate · 35 min

Mecanum Wheel Kinematics: Four Wheels, Three Axes

One roller at 45° gives you the whole matrix — and a fourth equation nobody uses.

Read tutorial

Intermediate · 35 min

Closed-Loop Wheel Velocity Control With Encoders

Feedforward does the work, the integrator cleans up, and the robot finally drives straight.

Read tutorial

Beginner · 30 min

A4988 Wiring and Vref: Set the Stepper Current Limit

The one adjustment that decides whether your stepper works or burns: setting Vref with a multimeter.

Read tutorial

Intermediate · 30 min

Homing With Endstops: Machine and Work Coordinates

Why every CNC machine drives into a switch on startup, and what the number it sets actually means.

Read tutorial

Intermediate · 35 min

How Stepper Motors Work: Lag Angle and Step Loss

The lag angle is the whole of stepper motor behaviour. Learn it once and step loss stops being mysterious.

Read tutorial

Beginner · 25 min

Steps Per Millimetre: Belts, Lead Screws, Resolution

One number ties pulses to millimetres. Derive it, then prove it with a measurement.

Read tutorial

Beginner · 20 min read

Build a Line Follower Robot: Sensors to PID Steering

From IR reflectance sensors to a weighted error to smooth PID steering—how a line follower actually works.

Read tutorial

Intermediate · 45 min

From cmd_vel to Wheel Speeds: ROS 2 Differential Drive

Convert a Twist into left and right wheel speeds — kinematics, saturation, deadband, and a watchdog.

Read tutorial

Intermediate · 14 min read

Detecting Line Maze Junctions With an IR Array

Classify T, cross, left, right, dead end and finish from a reflectance array, and resolve the ambiguous cases.

Read tutorial

Intermediate · 20 min read

Differential-Drive Odometry from Wheel Encoders

Integrate left and right wheel motion into a mobile robot pose, then identify and calibrate drift.

Read tutorial

Intermediate · 16 min read

Flood Fill Maze Solving for Micromouse Robots

How flood fill turns a partly-known maze into a distance field a robot can descend to the goal.

Read tutorial

Advanced · 22 min read

Inverse Kinematics of a Two-Link Robot Arm

Why a two-link arm has two solutions, where it can and cannot reach, and what a singularity really is.

Read tutorial

Beginner · 22 min

The Obstacle-Avoidance Algorithm: Sense, Scan, Decide, Turn

The sense–scan–decide–turn loop that lets a robot avoid obstacles on its own.

Read tutorial

Beginner · 20 min

Read an HC-SR04 Ultrasonic Sensor: Reliable Distance in Code

Turn ping-and-echo into a steady distance in cm—with a timeout and a median filter.

Read tutorial

Beginner · 20 min

Read an IR Reflectance Sensor Array for Line Following

Turn a row of IR sensors into a single, smooth line position you can steer on.

Read tutorial

Beginner · 17 min read

Sensor Noise, Bias, and Filtering in Robotics

Noise vs bias vs drift, choosing a filter without over-smoothing, and what sensor fusion can and cannot do.

Read tutorial

Beginner · 18 min

Servo-Scan an Ultrasonic Sensor to Find Open Space

Sweep an HC-SR04 on a servo to find the clearest direction before you turn.

Read tutorial

Beginner · 18 min read

How to Tune a PID Controller: A Practical Guide

A hands-on order for tuning P, I, and D gains without the guesswork—and how to try each step live.

Read tutorial

Intermediate · 25 min

Cross-Track Error: Measuring How Well You Follow

One signed distance tells you everything about a path follower — including which one to use.

Read tutorial

Intermediate · 30 min

GPS Waypoint Navigation for an Outdoor Robot

A GPS fix is late, noisy and has no heading. Here is what to do about each of those.

Read tutorial

Intermediate · 30 min

Pure Pursuit: Following a Path With One Knob

Aim at a point ahead on the path and drive the arc that reaches it. That is the whole algorithm.

Read tutorial

Beginner · 25 min

Bump Sensors and Debouncing for Robot Collisions

One press, nine transitions — and the interrupt counts every one of them.

Read tutorial

Intermediate · 30 min

Coverage Path Planning: Sweep a Whole Floor

Why a robot with no map needs seven times the distance to finish the same room.

Read tutorial

Intermediate · 25 min

How Hard a Robot Can Push: Traction and Weight

Two ceilings set push force, and on a small robot the floor is almost always the lower one.

Read tutorial

Intermediate · 25 min

Stopping at an Edge: Latency and Braking Distance

How far a robot travels past the line it just saw, and the speed that makes it fit.

Read tutorial

Beginner · 30 min

Reading Analog Voltages: ADC References and Dividers

analogRead gives you a ratio, not a volt. Get the reference right and the divider follows.

Read tutorial

Intermediate · 35 min

How to Choose a DC Gearmotor: Torque, RPM and Stall

Work out the torque and RPM your robot actually needs, then read a datasheet against real numbers.

Read tutorial

Intermediate · 30 min

Gearbox Backlash in Robots: How to Measure and Fix It

Every gearbox has play. Find out how much yours has, and what it is quietly costing your robot.

Read tutorial

Beginner · 30 min

How the I2C Bus Works: Addresses and Pull-Up Resistors

Every sensor page says connect SDA and SCL. This is what those two wires are really doing.

Read tutorial

Beginner · 30 min

Why delay() Breaks Robots: Timing With millis()

A robot sitting in delay() is blind. Replace it with millis(), and get the rollover comparison right.

Read tutorial

Beginner · 30 min

Why Your Robot Resets When the Motors Start

The reset that looks like a code bug is almost always the battery. Budget the current, then measure the sag.

Read tutorial

Intermediate · 30 min

Wheel Slip: Why Odometry Drifts and How to Fight It

Every odometry page says slip ruins the estimate. This is what slip is and what it costs.

Read tutorial

Beginner · 30 min

8051 Architecture: Pins, Memory Map, and Registers

Harvard core, four ports, 256 bytes of RAM, and timing you can count in machine cycles.

Read tutorial

Intermediate · 15 min read

LSRB Path Simplification for Line Maze Robots

Record turns as L, S, R and B, then collapse every dead-end detour into the optimal route.

Read tutorial

Beginner · 28 min

8051 GPIO and Port Interfacing: Sink, Don't Source

Why 8051 LEDs are wired backwards, why you write 1 before reading, and what a port can drive.

Read tutorial

Intermediate · 35 min

8051 Timers and Software PWM for Motor Control

Build PWM from a Timer 0 interrupt, pick the frequency-resolution trade, and drive an H-bridge.

Read tutorial

Intermediate · 35 min

Lidar for Robots: What a Scan Gives You and How It Becomes a Map

A scan is not a snapshot: sampling gaps, motion smear, and the ray casting that turns range data into a map.

Read tutorial

Beginner · 1 hour

Install ROS 2 on a Raspberry Pi and Build a Workspace

Choose the OS, install ROS 2 from apt, build a colcon workspace, and get a laptop talking to the robot.

Read tutorial

Intermediate · 40 min

Motion Profiles: Trapezoidal and S-Curve Acceleration

Ramp a move instead of commanding it — trapezoidal profiles, jerk limits, and what S-curve actually costs.

Read tutorial

Intermediate · 25 min

Robot Arm Types: Cartesian, SCARA, Delta and 6-Axis

Four architectures compared by workspace, stiffness and speed — and the kinematics duality between them.

Read tutorial

Beginner · 1 hour

Control a Robot Over Bluetooth With an HC-05 Module

Pair an HC-05 with your phone and drive a robot over Bluetooth serial, without the classic 5 V mistake.

Read tutorial

Advanced · 2 hours

Cascaded PID Control for a Self-Balancing Robot

Two nested PID loops: one holds the tilt angle, one asks for a lean so the robot can go somewhere.

Read tutorial

Intermediate · 1 hour

Complementary Filter: Fusing Accelerometer and Gyro Data

Fuse a noisy accelerometer with a drifting gyro into one trustworthy tilt angle, in a single line of code.

Read tutorial

Intermediate · 1.5 hours

Drive a Robot From a Browser With an ESP32 Web Server

Serve a control page straight from an ESP32 so any browser can drive the robot — no app needed.

Read tutorial

Beginner · 45 minutes

Reading Tilt Angle From an MPU6050 Accelerometer and Gyro

Turn raw MPU6050 counts into a tilt angle in degrees, and learn why neither sensor works alone.

Read tutorial

Intermediate · 1.5 hours

Wall Following and Precise Turns for a Maze Robot

Stay centred between walls, and turn exactly 90° — the two skills a maze robot lives or dies by.

Read tutorial

Intermediate · 18 min read

Drive Servos with the PCA9685 (I²C PWM Driver)

Set the frequency, turn angles into pulse widths, and move sixteen servos from two I²C pins — safely powered and calibrated.

Read tutorial

Intermediate · 21 min read

A* Path Planning on an Occupancy Grid

Build and validate an A* grid planner with safe heuristics, obstacle inflation, and route reconstruction.

Read tutorial

Intermediate · 22 min read

Camera Calibration and ArUco Pose with OpenCV

Calibrate camera intrinsics, validate reprojection error, and estimate an ArUco marker's 3D pose.

Read tutorial

Beginner · 18 min read

Control DC Motors with PWM and an H-Bridge

Wire and control a brushed DC motor safely using PWM, an H-bridge, and realistic current limits.

Read tutorial

Beginner · 17 min read

Finite-State Machines for Robot Behavior

Replace tangled robot conditionals with explicit states, events, transitions, timeouts, and recovery.

Read tutorial

Beginner · 17 min read

Read Quadrature Encoders for Distance and Speed

Turn quadrature encoder pulses into reliable wheel direction, distance, and velocity measurements.

Read tutorial

Beginner · 19 min read

ROS 2 Nodes, Topics, Services, and Actions

Choose the right ROS 2 communication pattern and inspect how nodes exchange robot data and commands.

Read tutorial

Intermediate · 20 min read

ROS 2 TF2 Coordinate Frames for Mobile Robots

Build and debug a TF2 frame tree from map and odom through the robot base to each sensor.

Read tutorial

Intermediate · 21 min read

SLAM, Mapping, Localization, and Odometry Drift

Connect odometry, range sensing, mapping, localization, scan matching, drift, and loop closure.

Read tutorial

Beginner · 18 min read

Ultrasonic vs Time-of-Flight Robot Sensors

Choose, mount, calibrate, and test ultrasonic or time-of-flight sensors for obstacle detection.

Read tutorial

Prefer to build something?

Browse by the system you want to make.

Every project guide includes theory, a real algorithm, downloadable diagrams, a component checklist, and an interactive simulator.

Explore project library