Page 188 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

Another contemporary of Walter, Hans Berger, invented the elec-
troencephalograph (EEG) machine. When Walter visited Berger’s
laboratory, he saw refinements he could make to Berger’s EEG
machine. When he did so, the sensitivity of the EEG machine was
improved, and new EEG rhythms below 10 hertz (Hz) could now
be observed in the human brain.
Walter’s studies of the human brain led him to study the neural
network structures in the brain. The vast complexities of the bio-
logical networks were too overwhelming to map accurately or
replicate. Soon he began working with individual neurons and the
electrical equivalent of a biological neuron. He wondered what
type of behavior could be created using just a few neurons.
To answer this question, in 1948 Walter built a three-wheeled turtle-
like mobile robot. The mobile robot measured 12″ high and about
18″ long. What is fascinating about this robot is that it used just two
electronic neurons but exhibited interesting and complex behaviors.
The first two robots were affectionately named Elmer and Elsie
(ELectroMEchanical Robot, Light Sensitive). Walter later renamed
the style of robots Machina Speculatrix after observing the complex
behavior they exhibited.
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Remember, in the 1940s the transistor had not yet been invented,
so the electronic neurons for the robot were made using vacuum
tubes. Vacuum tubes consume considerably more power than
semiconductors, and so the original robot was fitted with a rather
large rechargeable battery.

The robot’s reflex or nervous system consisted of two sensors con-
nected to two neurons. One sensor was a light-sensitive resistor
and the other sensor was a bump switch connected to the robot’s
outer housing.
The three wheels of the robot were in a triangular configuration.
The front wheel had a motorized steering assembly that could
rotate a full 360 degrees in one direction. In addition, the front
wheel also contained a drive motor for propulsion. Since the
steering could continually rotate a full 360 degrees, the drive
motor’s electric power came through slip rings mounted on the
wheel’s shaft.

The photosensitive resistor was mounted onto the shaft of the
front wheel steering-drive assembly. This ensured that the photo-
sensitive resistor was always facing in the direction that the robot
was moving.

Team LRN
Behavioral-based robotics, neural networks, nervous nets, and subsumption architecture