Tinkerbot

build a little robot one part at a time, and wake it up.

a story in six chapters, in 3D: put a robot together on a cutting mat, wire its battery and motors, give it ultrasonic eyes and time their echo, set the distance its rule turns at, then lead it to its charger by moving boxes in a cardboard arena

A robot is a body, senses and a rule. Without a wire from its battery nothing happens; wired to its motors it moves, but it is blind and drives into the box. Its eyes are an ultrasonic sensor: one side sends a click of sound too high to hear, the other listens for the echo. Sound in air travels about 343 m/s, so a box 40 cm away sends the echo back in about 2.3 thousandths of a second, and the robot works the distance out from that time (the card draws the sound hugely slowed down). Sensors like this read from about 2 cm to 4 m. Then the rule: it reads its sensor many times a second, and when something is closer than its line it stops, looks right, looks left, and turns toward the side with more room. Set the line too short and it cannot stop in time. In the arena you never drive it: you move boxes, and it turns where it finds them. A robot vacuum, a car's parking sensor and a rover on Mars all run a loop like this one: sense, decide, act, again.

Concepts: feedback-loops, sensors, echolocation.

An interactive you play with one thumb, on Wundr.