Common Engineering Sense

Normally I am all in favor of, and like, the way that the skeptical community tests some of the unlikely claims of companies and individuals who are trying to sell a product or service to the gullible public. The approach usually has some scientific rigor that easily exposes the flaws, or the hype. Some things, however, can be discounted with just a little engineering common sense.

Take the ADE 651 bomb detector, for instance. This is a device that is currently being used in Iraq and other conflict areas for detecting explosives. It consists of a belt-mounted box and a hand held unit from which a rod protrudes. The rod is free to move horizontally and point to guns and explosives. If this sounds a bit like dowsing, you’re right. But forget about that for a moment. Let’s look at this without preconceived notions, but rather with some engineering common sense.

First, the control module. Into this are fed cards programmer for specific explosive types. Okay, then we need scanning circuitry in the box and a chip or barcode or magnetic strip on the card. The BBC, on a similar unit, found the box to be empty and the cards to have RFID tags similar to the security tags on a CD package. Whether this kind of tag would be enough to change settings is questionable, but even if it could, an empty box can’t read it. First red flag.

Now the hand unit. The rod swings freely with the slightest movement of the operator’s hand. No engineer worth his salt would design a product where the primary indicator is sensitive to how the user holds the thing. Imagine if your GPS were to tell you to turn left one day and the next day tells you to turn right, just because you have a passenger or because it is raining. Second red flag.

Closely following that are the instructions which state that the user must be relaxed and in a good state of mind before using the unit. This is something you will never see in engineering requirements or specifications. Third red flag.

Finally, let’s look at the power source. Oh, wait, there isn’t one! The instructions say that the operator must shuffle his feet to build up the static electricity to operate the device. Even if this could be done reliably, this would only build up a charge in the person. Without a discharge path there is no current and no power. Final (huge) red flag.

So even if you didn’t know that dowsing is a crock, would you buy any of these to protect yourself and others? Of course not. But who is to blame here, the slimy manufacturer or the credulous purchaser? If this was a harmless dowsing rod that entertains a fringe group of believers, I’d say the latter. But people are dying because of these things so I think both are responsible. And even if we say that the buyers were well meaning but ignorant, we would have to question how they could possibly be in that position and not have the sense that almost everything we carry around these days at least needs a battery.

So no scientific testing was really required here. Just some good engineering common sense shows these things to be what they really are: a fraud.

More here: http://en.wikipedia.org/wiki/ADE_651 and here.

Published in: on February 22, 2010 at 8:37 am  Comments (2)