Another great example of a Sherlock Ohms story where the engineer had to figure out something very obvious that is easy to overlook -- that is, that most wooden furniture has metal nails. Good sleuthing.
Every time a parameter is changed, you have to reanalyze the test. Something as simple as a table might seem innocent, but I will be checking out my tables and other fixtures when I don't get desired results with no explanation. Good job!
Some years ago we were involved in certification of an ISM band product at an FCC approved lab. One of the resident engineers gave me a tour of the facility and showed me a large test room on the roof of the building built mainly of wood. He proudly explained how the structure had been assembled with no metal fasteners anywhere. I would expect the test lab to have a sense of professionalism.
Reminds me of an occurance years ago when I was an automated sewing eqipment technician. This was back in the day old fashion "electric eye" sensors were still crude. An operator reported a problem that the machine seemed to have a mind of its own and would activate for no apparent good reason. After severl attemps at adjusting the sensitivity of the "eye" and various other adjustments the problem would appear to be resolved only to re-occur the next day. This went on for several days and I finally recruited the assistance from one of our engineers. We both went through every conceivable theory and process as to what could be causing the problem when out of the blue he asked me to walk away from the machine. "Miraculously" the problem stopped only to start again as I got closer. The engineer then asked me to change my shirt, without giving any reasonable explanation. Being in a sewing plant this was not hard to do. I simply walked to the end of the line and chose a nice black sweatshirt that had just been completed. Problem fixed. it seemed there was just enough sunlight from a nearby window that would reflect from my previous white shirt just enough to cause the sensor to activate. No problem on a cloudy day but if clouds were moving across the area the reflection problem seemed to just be random. This was another example of a much simpler overlooked but not so obvious baffling situation. Final solution---put a piece of cardboard over the window. There, that fixed it.
Yes, it was a good job, Warren. The trick is to think of the hidden metal in a wooden table. I remember in the late 1970s, Sandia Labs was testing aerospace equipment and needed a mammoth wooden structure -- about 100 yards long, 50 yards wide. It was built entirely with wood. No nails because metal would interfere with the testing.
On the southwest corner of the campus at Worcester Polytechnic Institute (Worcester, MA) stands a stone building used some time ago as a magnetics and electricity lab. It contains no magnetic materials. Read a short history and see a photo here: http://www.wpi.edu/about/tour/skull.html. The street-car line no longer exists. I cannot vouch for the veracity of stories about the Skull society and any "secret" ceremonies.
I heard a story about engineering students who created a wireless robot that would crawl through metal pipes. The robot would into the pipe, but at exactly the same point it would stop communicating. Turned out the pipe formed a nice waveguide and acted like a dead short for the RF, so communications ended abruptly. My memory is a bit hazy, so maybe some other waveguide effect caused loss of comms--I'm not a microwave guy.
In an age of globalization and rapid changes through scientific progress, two of our societies' (and economies') main concerns are to satisfy the needs and wishes of the individual and to save precious resources. Cloud computing caters to both of these.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.