In 1949 neurophysiologist Grey Walter built two robot “tortoises” to show that complexity could arise out a very simple nervous system. “Elmer” and “Elsie” each had a light sensor, a touch sensor, a propulsion motor, a steering motor, and two electronic valve-based “neurons.” He found that even with this modest equipment they were capable of phototaxis, finding their way to a recharging station when their batteries ran low. In a subsequent experiment he watched as a robot moved in front of a mirror and responded to its own reflection. “It began flickering,” he wrote. “Twittering, and jigging like a clumsy Narcissus.” He argued that if this behavior were observed in an animal it “might be accepted as evidence of some degree of self-awareness.”

He found that other simple robots were capable of Pavlovian conditioning. When a robot had been taught to seek its “food” near a stool in the middle of the floor, Walter took to blowing a police whistle and kicking the robot before it found the target. “After it had been whistled at and kicked about a dozen times, it learned that a whistle meant trouble. We then removed the specific stimulus — the stool. The whistle was blown, and it avoided the place as if there were a stool there.”

He advanced to a two-note whistle: One pitch was sounded before the robot touched an object, to associate it with avoidance. The other was sounded before it found its food, to associate it with appetite. “The effect of giving both notes was almost always disastrous; it went right off into the darkness on the right-hand side of the room and hovered round there for five minutes in a sort of sulk. It became irresponsive to stimulation and ran round in circles.”

“As you would expect, there are only three ways of alleviating this condition. One of them is rest; in this case that was sufficient, it was left alone to play around in the dark until the effect of all the trauma had died down and it found its way home in the end. Another method is shock, to turn the circuits right off and start again with a clean bill. The most satisfactory method for my purpose is surgery, to dissect out the circuit.”

(Philip Husbands, et al., The Mechanical Mind in History, 2008, and J.M. Tanner & B. Inhelder, eds., Discussions on Child Development, 1958.)

Idaho farmer John Barnes patented this “coyote alarm” in 1903. Near his sheep pens he mounted a man-shaped scarecrow wearing a metal breastplate. In the breastplate was a cylinder “analogous to the cylinder of a revolver of large size” holding blank cartridges. A clockwork mechanism turned the cylinder, and a plunger dropped at intervals and fired a cartridge. Barnes would wind up the mechanism with a key at dusk, and the artificial farmer would fire its imaginary gun “every quarter of an hour throughout the night.” I wonder what the sheep thought of this.

This is actually less alarming than James Williams’ pest exterminator of 1882. That’s progress.

Raymond Richards had a peculiar notion of safety — his fire alarm, patented in 1966, consisted of a string of firecrackers:

[I]t is proposed to provide an elongated tube having a plurality of spaced firecrackers disposed in its bore, each firecracker having its own fuse located in proximity to a main fuse, the latter extending longitudinally through the bore of the tube, with its opposite ends being exposed for being ignited by an adjacent fire.

The tube of firecrackers would be pinned to a drape, and caps on the tube would discourage children from playing with it. What could go wrong?

Robert Patch of Chevy Chase, Md., was only 5 years old in 1962 when he designed a toy truck that could be converted into a flatbed or a dump truck by altering the placement of the axles. His father, a patent attorney, saw that the truck’s design was unique enough to be patentable, so Robert signed the application with an X and had the mark witnessed by a notary public. When the application was granted, Robert became the youngest person in history to receive a U.S. patent.

The publicity meant nothing to him, but it did bring one benefit. He had made his working model from bottle caps, Scotch tape, nails, and old shoe boxes. Someone at US Keds, the shoebox brand, saw the story — and sent him a new pair of sneakers.

In 1915, Vermont inventor Albert Pratt proposed a new weapon: a head-mounted gun. You strap the helmet to your head and hold a hollow tube in your mouth; when you blow through the tube, the gun fires a bullet at whatever you’re looking at.

“The weapon described has many advantages,” Pratt writes confidently. “The gun is automatically aimed unconsciously and incidentally to the turning of the head of the marksman in the direction of the target. In self-protection, one immediately, instinctively turns the head in the direction of attack to see the enemy, or, in hunting, toward any sound made by nearby game. Thus the gun is automatically directed toward the mark in the course of the first instinctive movement. With the gun thus aimed, the only further operation necessary to fire the same is to blow through the tube and thereby expand the bulb and operate the trigger. This is accomplished entirely from the head of the marksman, leaving his hands and feet free further to defend himself or for other purposes as desired.”

“Under some circumstances the gun can be fired not only without the use of the hands and feet, but also without the use of the eyes of the marksman. For example, in hunting at night if an animal made a sound in underbrush, the head of the marksman would be instinctively turned in the direction of the sound and then the gun would be fired, without the use of the eyes of the marksman.”

If that’s not enough, Pratt also says that the helmet can be detached from its base and used as a cooking utensil. “The spike may be stuck in the ground to support the utensil or may be detached therefrom as desired.”