Dendrites

Overview

Four small robots built in 1999 for the Intelligent Machines Design Laboratory course at the University of Florida, made to show that very cheap hardware could let robots find each other, exchange messages and play children’s games together, about 12 years before the Kilobot. Each Dendrite has five infrared LEDs and five infrared receivers around its body, which serve as obstacle sensors, as a way to tell which direction another robot is in, and as the message link (range about 5 feet). A first protocol that gave every robot the others’ positions plus an 8-bit message needed about 2 seconds per cycle, so it was replaced by simpler pulse schemes built around each game. In Tag two robots trade infrared pulses about every 250 ms and the leader signals a tag with a long pulse, in Simon Says the leader encodes a move as a pulse length in 200 ms steps and the others re-broadcast it so the command spreads down a line like the game Telephone, and in Follow the Leader only the leader has a light sensor while the others follow its infrared beacon, which the report calls virtual sensor sharing. The report rates the project a moderate success, since the leader’s bump ring missed at least two-thirds of contacts and a chasing robot near a wall would sometimes follow reflected infrared instead of the other robot.