Building Construction, Renovation, Maintenance & Advice

Household Sensors

"Gremlins and the New World Order"

We have all come across those strange stories about people who walk under street lamps and make them go out. Some people consider this perfectly possible however, from a technical point of view, it is as likely as Rasputin being invited to a meeting of the policy committee of the Islamic Defenders Front.

People zapping computers with lightening bolts however is a whole other matter. Years ago I got first hand experience. I was sharing a house with a woman who had a bit of a problem. She would turn on her computer and within minutes of sitting at the keyboard the thing would crash. Yes I know that happens to most of us, most of the time, but this was not your average crash, the grey box would crackle and pop and the screen would flash and go blank. This had been going on for rather a long time, a period of years rather than hours, and she was starting to get just a little bit lacking in the happiness and contentment department.

So I did what any neighbourly engineer would do, I drilled a hole in her left foot, bolted a piece of 6mm copper cable to it and fastened the other end to a 4 metre copper rod which I drove deep into the garden. Nothing like a good bit of grounding to suppress a throng of over exuberant anarchistic electrons.

She sat down, smiled at me thankfully and switched on her computer…. As usual a particularly lazy dose of time crawled by during which you wonder what exactly is going on in there and if you have been conveniently forgotten by that little man who loads up the hard drive. Then suddenly, without warning, flash, pop, kerzap! - it crashed.

After trying everything and anything I could think of I eventually gave up and went back to cutting my toe nails. I put it down to a highly charged woman or perhaps a dose of "gremlins".

Of course we all know about gremlins don't we? We come across them all the time.

Gremlins are those mischievous little sprites that inhabit mechanical and electronic devices and interfere with their workings for the sole purpose of causing as much bother as possible. Some rather naive people think they are imaginary but I can assure you that rather a lot of people have spent many years researching and creating "gremlins". To the technical world gremlins are very important. They are a constant reminder that we should not take technology for granted, they maintain the mystique and of course they provide a never ending supply of work to service centres.

Gremlins are bad enough but a far more sinister creature is a "neurogrem. A neurogrem is, of course, a gremlin that is able to sense activity in the neural pathways of the brain, put simply - they can sense our mood.

So where did the idea of neurogrems originate? This has been a topic of considerable conjecture among technical experts for many years but I have a sneaky suspicion it has something to do with photocopiers. Have you never noticed that those machines are alive? Somehow they know that you are in a hurry or stressed and immediately they start jamming, chewing up paper or running out of toner.

The photocopier was, of course, invented by a man called Jester Carlson back in 1938 and it is said that he was a bit of a practical joker with a disturbing sadistic streak. He invented a rather clever machine for photographing and printing images but he just couldn't help himself, he had to keep reminding people that his machine was firmly in control and that we would have to be patient.

The secret to Jester's device was a "sensor" which sits in the bowels of the photocopier waiting to wreak havoc on any unsuspecting poor soul who is in any way stressed, irritable or grumpy and needs a copy fast. He managed to develop gremlins that were able to tune into our emotional state of mind. He created the first neurogrems.

Sensors were an unusual concept back in 1938 but are very common these days and in fact we unknowingly are surrounded by them. They make our lives easier by providing control (or chaos as the case may be) and in many ways they manage our lives.

They operate day in day out waiting for information and ready at a moment's notice to make a decision and adjust something for us.

A sensor is the main component in equipment feedback systems. A machine or piece of equipment uses a sensor of some kind to measure or take note of something and feeds the information back to the machine to switch itself on, switch itself off or adjust something.

One of the early forms of sensor is the trusty ball valve used for over a hundred years in toilet cisterns and water tanks. The ball floats on the surface of water and "senses" when the water level falls, it opens a tap allowing water to flow into the tank until the water level is restored.

We all know what useful devices ball valves are, when the valve stops working we lose our sense of harmony with the world and end up having to find buckets to fill up the toilet cistern.

Most of us use water pumps to pump water from a bore and to pump water through our household plumbing systems. Household water pumps usually have 2 pressure sensors. A low pressure sensor which switches the pump on and a high pressure sensor that switches the pump off. The majority of problems we have with our water pumps are caused by faults in these pressure sensors.

We are all familiar with air conditioners and refrigerators and their temperature sensors which, once again, switch the machine on or off depending on the temperature the sensor reads.

Some sensors are very important and keep us safe.

Water heaters have thermostats to measure the water temperature and switch off the electric heating element. If the water gets too hot and starts to boil we may be in serious trouble.

Many gas appliances have heat sensors that sit in the gas flame to detect if the flame goes out. If the sensor goes cold it will know the flame has gone out and switch off the gas supply.

Our electrical circuits have contact breakers that detect if the flow of electricity is more than it should be. A high flow of electricity suggests a fault in an electrical circuit such as a short circuit that can cause fire. A high flow of electricity causes the circuit breaker to switch off the power supply. Before we had modern circuit breakers we had fuses to cut the power off . These worked by melting a thin piece of wire if they got too hot. By the way, believe it or not, some old houses still have fuses, if your house has fuses it is a good idea to replace them with circuit breakers particularly bearing in mind that many fuses were "fixed" with such sensible things as silver foil or bits of wire.

Designers of these various sensing devices tend to make sure that if they fail they will fail in the safe position. You will find that if your thermostat fails in your water heater the heater will not switch on. Similarly if the gas heat sensor fails you will not get the gas to flow.

In more recent times we have smoke alarms to detect fire and sprinkler systems that automatically turn on the water if they detect heat.

Obviously sensors of various kinds play an increasingly important role in our lives, By combining sensors with clever electronic systems and mini computers they are becoming increasingly programmable. A whole science has been built up and is known as "control engineering" that is applied to many applications in our modern world such as controlling automated production lines, traffic systems and war machinery such as guided missile systems and robotic attack aircraft. BP are in the poo at the moment but how would they have got on without the availability of remotely controlled submersibles.

At a more local level we are all familiar with televisions that are able to tune themselves automatically. I have a satellite television system that picks up free to air television stations from around the world. It has a satellite dish that can move from one satellite to another to pick up a large number of programmes (ever watched "Neighbours" in Swahili?)

Sensors are used to accurately determine the position of the satellite dish, to measure the signal strength and to receive any instructions I may give it by using my remote control and selecting any particular programme.

It can be easily appreciated that in an ever more sophisticated world there will be more and more opportunities for neurogrems to play their mischievous games and, of course, Murphy's Law dictates that it will always be when the cup final is on or when the boss and his wife have come to tea.

When it does you now have the perfect excuse, you can blame the neurogrems.

Copyright © Phil Wilson 2009
This article or any part of it cannot be copied or reproduced without permission from the copyright owner.

8 February 2017 Copyright © Mr Fixit,
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