Amateur robotics is a fun and worthwhile hobby. It encourages scientific interest in children and students, who may grow up to be engineers and scientists. And for adults, it allows us the lifetime pursuit of knowledge and experience.

Robot building combines machining, electronics, mechanics, art/aesthetics, and programming into the most expensive, obstinate, yet rewarding lifeform you can create outside of a human being. In hopes that you, too, will live your dream of becoming robot builder, here are photographs, circuits, and descriptions of most of the robots that I have made:

StreamHawk remote-controlled semi-autonomous exploration robot Wireless Video and Speech Telepresence Robot
Movies, photographs, tips, and instructions for a remote-controlled semi-autonomous wireless robot that navigates with dead-reckoning from Maxon motor encoders. The motherboard includes an Atmel ATmega644 microcontroller, four Infineon TLE-5206-2 motor drivers, Panasonic IR remote receiver, and I2C communication. The robot also includes a Devantech speech module.
A tiny robot that fits inside a Monkey Mints candy container. Monkey-Mints Micro Line-Following Robot
A robot that fits in the palm of your hand, built into an Accoutrements candy container. Features ultra-small gearmotors with surface-mount motor driver transistors. Includes a video with interesting patterns that appear as the robot sweeps aside candies.
A small robot that drives back and forth Back-And-Forth Robot
A robot that drives forward to a wall and returns is a popular contest and student project. Surprisingly, this robot can be made with an off-the-shelf 8-pin motor chip, a couple of resistors, and a couple of chips. The article provides a complete walkthrough of the schematics, along with an animation of the changing states and a video.
Back And Forth Mark II robot thumbnail Back And Forth Mark II
The single motor drive train on the original Back And Forth robot was unique but a failure. To overcompensate, the next generation is four wheel drive and six switches just to move forward and move back, repeatedly. There are some nice mating parts that may be useful in your next project. And, you'll be surprised to see what's inside the half-height batteries.
Sandwich, the line-following robot Sandwich, the Line-Following Robot
This is a simple, yet sleek, line-following robot that you can reproduce in your home laboratory. A racetrack movie appears at the end of the page.
Afterthought Cake thumbnail Afterthought Cake Robot
A pleasant robot that doesn’t do much consists of a collection of interesting parts assembled together because they didn’t fit any other robots. The robot is a successful experiment in making couplers shorter, employing escap rectangular motors, detecting distance moved with an interrupter infrared encoder, and a cube of multiple smaller PCBs. Powered by a single 180 mAh lithium polymer cell without a voltage regulator. Motors driven using low-voltage high-current Zetex bipolar transistors. Includes lots of big pictures and a descriptive demonstration movie.
Candy-container robot with front bumper switch Flip-Flop Robot
This robot drives forward until the front bumper hits an obstacle. Then, the robot reverses until the rear bumper hits an obstacle. An easy-to-build robot for beginners. No machining or microcontroller required.
Roundabout, the line-following, room-exploring, mini-sumo robot Roundabout
This is an all-in-one intermediate-level robot that can explore rooms, avoid obstacles, follow lines, and compete in mini sumo (see the movies). The robot can be made in a variety of body styles with either a logic chip or microcontroller brain.
An Atari joystick Controlling a Robot with an Atari Joystick
Every once in a while, a project turns out really well. This is one of my favorites. Using a classic Atari or Commodore joystick, you can make a simple circuit to control a robot or other electronic device. Includes a schematic that does not require a microcontroller or even a voltage regulator. Also discussed is how to modify a Solarbotics GM7 motor for easy mounting to a Lego Technic frame.
Power switch with target Robotic Kill-Switch Target
Mounting a robot’s power switch in the front adds a new method of defeating an opponent in robot combat. Rather than sustaining major damage, the robot can be disabled by hitting the snap-action switch. Schematic and photographs included.
No.2 sumo robot thumbnail No.2 Mini-Sumo Robot
Pictures and videos of a champion mini-sumo robot that defeats opponents with pencils (yes, seriously). The robot has a 360-degree infrared opponent detection system and large LEGO wheels with embedded motors.
Go! Go! Go! Bugdozer autonomous mini-Sumo bot Bugdozer Autonomous Mini-Sumo Robot
Based on an MC68HC908GP32 microcontroller, this pulse-width modulated 18-volt dc scoop-on-wheels saw combat in November 2000. Using two 38-kilohertz infrared sensors and 4-front/1-rear near-red phototransistors, Bugdozer tries to push opponents out of the ring while staying within the white borders herself.
Carefree thumbnail Carefree Robot
A room-exploring robot with a variety of sensors (whiskers, snap-action switches, shadow detectors). It has an unusual serial motor driver and a special image etched into the motherboard PCB.
XS Boost, a solar-powered chef’s-salad robot XS Boost, Chef’s Salad Solar Robot
Includes some unusual parts, such as N-size cells, tilt switches, and a finger-friendly dipswitch. It has a very efficient solar engine that uses a Maxim voltage doubler chip to power Maxon motors. As such, this robot runs constantly in moderate sun (no pauses between bursts).
Lightspeed thumbnail Lightspeed Solar Roller Racer
Robots that race straight to a finish line, powered only by light, are called Solar Rollers. Lightspeed is a champion racer with a mix of modest LEGO bricks and an expense Maxon motor in a custom machined interference-fit mount. The design also features a hybrid PCB with prototyping sockets.
Appetizer robot seeking the sun Appetizer Robot
This solar-powered robot is built with a BEAM design. Small dc motors are driven by a capacitor and steered by photodiodes. Photographs, links, a video, and a schematic are provided.
Chicago, the solar line-following robot Repairs and Improvements
Visit Sweet, Roundabout, Hard2C, and Chicago for a weekend of simple fixes for line following, mini sumo, and solar power. See how different types of screws can help a robot slide, hide, and hold onto a gear.
Sun Tracker thumbnail Sun Tracker Failed Project
Sometimes you gotta know when to walk away -- which was eight years ago. I dug up this robot that was supposed to emulate a sunflower tracking the sun. Due to a design flaw in an overly complicated analog sensor bus, and general ugliness, this project got literally shelved. Now it sees the light of day, if only to be a lesson to others.
Wavy thumbnail Wavy - Line Follower
The predecessor to the popular Sandwich robot, Wavy has some extra components and some missing components in comparison. This is one of my favorite robots, particularly for its exaggerated line-following motion.
Jet, the fast line-following robot Jet, the Ultra-Fast Line-Following Robot
Learn the technical extravagance that competition leads to, as a line-following robot breaks the 100 cm/s barrier. Includes plenty of techno-babble and names of people you don’t know.
A robot solves a maze of lines Line-Maze Solving Robot
A multi-deck robot with seven PCBs, nine floor sensors, one LCD, four buttons, and two quadrature encoders. The robot solves mazes made of white lines on black tiles. The article includes two movies.
H.A.N.D. thumbnail Have A Nice Day - Sumo Robot
Driven by eight wheels and two Maxon motors, this LEGO-bodied robot shoves off competitors using a powered drop-down spatula-style scoop. Despite multiple sensors, three motor drivers, status LEDs, and a pushbutton, the robot is controlled by a simple 16-pin microcontroller.
Chicago thumbnail Chicago Solar-Powered Line-Following Robot
This robot combines two circuits from other robots to charge/discharge 2 farads of capacitance into a pair of miniature motors controlled by a low-voltage comparator. Four photosensors track the line, which can be either dark or light based on a switch setting.
Hard2C thumbnail Hard2C Mini Sumo Robot
A mini sumo robot that is compact and painted black to avoid detection. It uses Sharp distance sensors, a 1 millimeter scoop, and floods opponents with red and infrared light. Learn about the flaws that prevent it from winning most sumo matches.
Parallax Boe-Bot Robot thumbnail Parallax Boe-Bot Robot
A review of a well-engineered commercial robot kit for hobbyists and students.
LEGO MindStorms Chipmunk Chaser Robot thumbnail LEGO MindStorms Chipmunk Chaser Robot
Snapshots and some design notes of a robot built with LEGO MindStorms bricks.
A fun line-following robot. Sweeeeet! Sweet! The Line-Following Robot
An m&m’s candy container provides a fun body for a smart line-following robot. Videos show the auto-contrast, dark-or-light detection capabilities. Sharp turns and crossovers don’t slow this car down, but it can automatically stop at the end of the line.