No, we're not talking about Russian hackers monitoring your ablutions. But yes, you might say there's a computer in your toilet although it stretches the definition. That would be the float in the cistern that detects the water level and opens the valve until it's full.
That's an extremely simple form of computation, is it not?
We could even classify it as a digital computer since the tap is either ON or OFF. Ergo, your toilet has a single bit (binary digit) processor, albeit a mechanical rather than an electronic one.
However, if it allows the valve to be partly on or off, we'd say it's an analogue computer.
While the proliferation of cheap microchips has meant digital computers have mostly taken over, analogue computers have been around for a long time. Surprisingly, they could do sophisticated jobs.
Far less benign than our toilet example is the acoustic torpedo developed during WWII by the United States Navy and German navies, with the first verified combat kill by the former in May 1943.
The nose of the torpedo contained transducers that acted as microphones.
If a transducer on the left side detected a louder sound, it would steer the torpedo in that direction. Conversely, a louder sound on the right would steer to the right. For greater accuracy, multiple transducers were used.
The German T5 torpedo could travel at 44km/h, with an effective range of about 5 kilometres. Electronics connected to pneumatic valves to steer the rudder (which, oddly enough, is a crude parallel to the toilet "computer").
To minimise confusion with other sound sources, the transducers were tuned to the pitch of ships' propellers. If it worked properly, it would explode under the ship's stern.
The first uses of the T5 did not always go well. Reportedly, the crew fired a torpedo which, hearing the nearest vessel, circled around and blew themselves up.
To avoid that problem, they locked the homing system until the torpedo was 450 metres away from launch. The submarine would dive to 60 metres, going into silent mode.
While the T5s were a potent weapon (700 were fired, sinking 77 Allied ships), the countermeasure was simple. The British "Foxer" acoustic decoys were towed several hundred metres astern of the ship, confusing the torpedo's homing system until it ran out of fuel.
The biggest difference with what we think of today as computers, is that these devices have fixed logic. Although some of their settings can be changed (such as adjusting the height of the cistern), their programming is hardwired.
That innovation first appeared in the "Baby" computer developed by the University of Manchester in June 1948.
And finally, for a bizarre coda to this story, search online for "computer" or "smart" toilet. Yes, apparently it's a thing.
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