|
Personal Digital Literacy
|
|
|
|
|
 |
 |
 |
CREATIVE SCIENCE PROJECT #3
ELECTROMAGNETIC ERASER.
Disclaimer: As ever, usual disclaimers apply here. Microwaves are designed for cooking food, not electronic devices. If you carry out any experiments, then you do so at your own risk.
Personal Disclaimer: Any experiments I may or may not have carried out with microwaves, may or may not have been carried out whilst my partner was away. The smell was nothing to do with me, it was the cat.
Radio Frequency (RF) Identification tags are sometimes suggested as a way of tracking the life cycle of products. A good idea in principle, but given the volume of junkmail or spam email people receive thanks to personal information being freely hawked around, it is not hard to see how the use of RF ID tags could be used for more nefarious purposes, especially by those who are less scrupulous about personal privacy (.e.g. large corporates, governments, or marketing droids). After all, whilst an RFID tag is useful for shop stock taking or for security of items in a shop (both excellent uses to my mind). What business does any company/shop/government have in knowing where the item is once I have legitimately bought it, and it is out of the shop? I've bought it, it should be mine, and it is none of their business what happens to it. That should be the end of story. But no, they think they have a right to be voyeurs, and track the items even after they have been bought legitimately.
Luckily, for those of us who value some vestige of privacy, and don't want governments, companies, or eventually, even some nosy local councillor, knowing every time we get up from our chairs and go into our toilets, through the excessively intrusive use of RFID, the Laws of Physics come to our rescue again:
Take one RFID tag and one microwave oven. Place the RF ID tag in the microwave oven, turn the microwave oven on, and in a short space of time, you have demonstrated why Physics can be used very effectively to stop nosy morons in their tracks. This procedure can be done if the RFID tag is still embedded in the item, however, destruction of the item may be the result, so it is entirely at your own risk.
When an RF ID tag is placed in a Microwave Oven, and the Microwave Oven is switched on, the electronics in the tag is not destroyed by heat, but by inducing of a huge amount of current in the tag, instantly frying all the electronics. The RF ID tag generally has an antenna lead (frequently very short, but still present) to enable the RF tag to pick up the tiny RF signal that it uses for power. However, by placing the RF ID tag in a microwave oven, the tag is being supplied with many thousands of times more power than it's designed to take, with the inevitable destructive results that one would expect.
QUESTIONS ABOUT RF ID TAGS
RF ID Tags can only be read at short range.
...by store RF ID readers yes, but anyone who is naiive enough to think that that means they can only be read at short range full stop, doesn't really understand some fundamental laws of Physics, and as such, would be better off shutting up and not making a fool out of themselves.
Sensitive antennas and receivers which will significantly extend the range over which RD ID tags can be read, are not hard to construct. It is analagous to Wi-Fi or wireless networks - where the wireless cards for laptop computers were originally designed to be used over short ranges of a few hundred metres, but various ingenious solutions have been developed, even including devices such as Pringles cans as antennas, which have extended their ranges to kilometres.
RF ID tags operate at a different frequency (frequencies such as 13.56 MHz, as opposed to 2400 MHz for Wi-Fi), and are passive (i.e. do not transmit). However, nature is no respecter of human rules, and solutions to read RF ID tags at a distance, with high gain antennas and sensitive receivers can be produced.
RF ID Tags are no different to Barcodes.
Rubbish! Barcodes do not enable people to be tracked after they leave a store. RF ID tags do. Are you happy about people potentially knowing your whereabouts after you have left a store ?
But companies would never use the information from RF ID tags for uses I do not approve of.
You've obviously never met someone who works in marketing then ? Maybe you're one of those people who likes spam emails or junk mails, remember, the data used to send you that rubbish comes from lists you don't know about. Are you happy with people knowing your movements as well ?
RF ID Tag information wouldn't be used in a bad way.
Ever heard of identity theft ? Thought not. I've been a victim of it. Watch how rapidly you change your tune after it has happened to you. Suddenly, another method of gaining more information on you (i.e. via RF ID tags), doesn't seem so enticing.
Note 1:Microwave ovens make good test labs for studying electromagnetism - as long as you're prepared to write off your microwave oven if anything goes wrong. Anything from home made ball lightning to exploding grapes can be produced in them. One of the common experiments is to stick a CD or pop-tart wrapper in the microwave oven and see what happens. The arcs are caused by the high voltage induced in the conductive parts. BTW this won't hurt the microwave but it does stink. Please note that you do any of this at your own risk.
Note 2: I should know what I am doing - As well as collecting Physics degrees, I worked professionally on Microwave research, and still have to engage my brain on RF related things more than I'd like. Oh, and I can still write down Maxwell's Equations whilst drunk.
Note 3: I do have an old microwave oven which is used purely for testing of interesting experiments like this. I don't use it for food as well, since that might be a bad thing. Do try to avoid using your primary food microwave heating source for these experiments, or for that matter, someone else's primary food microwave heating source.
REFERENCE LINKS
|
|
|
|
Sun, Dec 22, 2024, 21:07 GMT
(123)  7:09  16:22  74
% |
|
home - space - research - links - contact me - colophon
Richard Osborne - 1995-2006 |
|
