I'm still on a stolen-car kick here, and all the talk of theft prevention and alarms got me wondering just how long car alarm systems have been around? The first recorded car theft happened to, of all people, a Baron. He moved to create the first car alarm.
Baron de Zuylen, an early and influential automobile enthusiast, had his Peugeot stolen in 1896, by his mechanic. Which may also be the first dirtbag mechanic in recorded history as well. Mechanisms to prevent cars from being stolen were probably at least imagined soon after that.
I'm sure the good Baron's first sketches of an anti-theft system involved guillotines and swinging maces, but for years the most effective anti-theft systems in a world of largely open cars was probably an irritated rotwieller on the passenger's seat. The earliest actual patent of something we would recognize as a car alarm seems to have been applied for patent in 1918.
The system is an actual, electric immobilizer/alarm system, invented by a pair of Portland men, St. George Evans and Edward Birkenbuel. They developed a very clever, fairly modern-seeming (to a degree) mechanism, especially when compared to other, much more mechanical attempts around the same time. For example, here's a system as described in the June 1920 issue of Popular Mechanics:
"A friction gear, thrown into or out of engagement with the shaft by a cam, is enclosed with the alarm in a riveted steel case, fixed to the shaft housing and radius rods. The cam also short-circuits the magneto, so that turning the key in the lock stops the engine and sets the alarm. The lock is located in the floor of the driving compartment."
Riveted steel cases, shafts, cams — that's a lot of heavy hardware to use for an alarm. What these Portland boys did that's so interesting is to make an all-electric system that even sort of prefigures more modern computer-based systems. Except your wet, sticky brain is the computer.
The Evans-Birkenbuel system utilizes a 3x3 grid of double-contact switches on a panel through which the current from the battery (or magneto) is routed when the car's ignition is activated. The current is either diverted to the spark plugs or the horn depending on the settings of the switches. So, the end results are either you get to start your car, or your horn blasts until your battery is dead. Not bad!
The way it's operated seems to be like this: the owner of the Franklin or Hupmobile or whatever sets a combination of the switches to their closed position via a special little key that allows the switches to be set without being able to see their positions. See, the switches are all in a box that numbers the switches and only provides access through small holes, hiding the switch position.
So, let's say you leave the car, and set switches 8, 4, and, oh, 3. That becomes your combination. Anyone trying to steal your car would need to know what switches you set, and trying to figure out the combination without seeing the switch positions would be really, really hard.
So, your brain is the computer that stores the combination of switches, and that combination can be reset every time you drive. It could also be as complex or simple as you want — 1 switch for just slowing a potential thief down, all the way up to... well, I guess 9, but then all switches would be on, which isn't much of a combination. After a point it becomes figuring out which to leave off, but not knowing any of that, it's still quite difficult.
It sort of feels like a 2D Rubik's cube, in a way. Same 3x3 grid, same result that the more you screw with it, the worse off you'd likely be. You could be very methodical, and try all combinations, but even with only two switches set the odds of finding it before the angry, 19teens-1920s owner comes back with one of those two-black-ball-circus-style barbells to whoop your ass with seems remote.
There's issues here— someone tampering with it could effectively keep you from starting the car as well, and that's hardly ideal. Still, considering the technology of the time it's a pretty impressive bit of hacking simple switches into a viable alarm. In fact, it'd be quite easy to replicate something like this today, using either relays or automotive switches that can handle 12V. You'd be faced with the same issues, but for a quick-cheap-dirty system, you could do worse.
I mean, I probably could have used one.