Slashdot Mirror
Erasing CDs By Using 150,000 Volts of Electricity
ryzvonusef writes "One enterprising individual has created the most secure way to wipe out Compact Discs, by using a step-up transformer and creating a 150,000 Volt pd, whilst a CD rotates in the middle. The sparks arc through the metal in the CD and evaporates it, ripping it all off as the CD rotates. The CD is rendered transparent and unreadable. This may be the most secure method to remove data on conventional recordable CDs used in offices."
Does a thorough enough job, almost everyone has one on hand, takes but 2 seconds an
Science geeks have been doing this for years with microwave ovens; though, it was more for the cool light show than for data security.
Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.
actually the foil is VERY quickly shattered, it's quite spectacular and is a good deal safer on the magnetron than the other article today where someone was suggesting microwaving a hard drive
I work for the Department of Redundancy Department.
That... was one of the coolest electricity displays I've seen in a long time.
Ta heck with what it does, lol
-AI
For me, it is far better to grasp the Universe as it really is than to persist in delusion
Most secure? My ass...
The microwave
A Fire
Paper shredder
Acetone
This is just an expensive toy
I've done it dozens of times. My 13-year-old cheapo microwave oven didn't bat a lid. Still going strong.
I think the "easy to damage the microwave" is an urban legend. Someone should submit it to Mythbusters.
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
Of course you can not read a CD if the reflective metal layer is removed. But the data is stored in tiny pits that are printed into the polycarbonate layer. If the polycarbonate is not damaged too much, the CD might be readable when a new metal layer is applied.
The most secure way to destroy CDs is either dissolving in acid or loaning them to my boss. I promise, you'd never see it again.
The thinking goes, the magnetron is basically an antenna, right? So it can pick up as well as transmit energy. If an electric charge builds up and arcs stright into the magnetron, it can blow up. Or something like that. I've never seen it happen, and I've blown up a lot of stuff in microwaves over the years.
A quick google search for "blow up the magnetron" turned up this answer from a microwave engineer:
2. metals in the microwave oven - they will not destroy the oven or cause it to blow up. I routinely heat my coffee with a spoon in the cup. I also did the definitive early research on this in the late 70's and early 80's. But it is possible for metals to arc (spark) under certain conditions. This can be dangerous especially with things like metal twist ties and steel wool. Also, things like the metal trim (silver or gold) around the rims of fine china is dangerous in that the dish or cup can easily beak or shatter - but this due to the trim not being perfectly continuous like a wire that would carry current, Instead the trim has microscopic gaps and that can cause micro-arcs and temperatures exceeding 1000 F locally.
Don't you just love the Internet? We get to be wrong more often, but not for as long.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
It's not an intuitive thing, don't worry you're not alone in not immediately seeing the problem.
A magnetron is a kind of RF (radio frequency) transmitter. It converts electrical energy into radio energy. This energy leaves the magnetron and bounces around inside the microwave. The frequency used makes it tend to interact with water molecules, and heats them up, changing radio energy into heat energy. And that's what heats the food. (note that foods with significant water content heat best)
The microwave is tuned just like an antenna is tuned, to maximize the use of energy. Energy the magnetron takes from electricity has to go somewhere. Energy sent into the box that isn't absorbed and converted to heat is reflected back to the transmitter. This is aka a "standing wave". The "Standing Wave Ratio" tells how efficient the energy transfer is.
A high SWR means a large percentage of the input energy is being reflected, and back to the transmitter where it must be used and so is converted into heat. Transmitters expect some of this because the conversion isn't perfect to begin with, but they're not designed to handle a LOT of additional energy to dump, and will overheat. Very high frequencies like magnetrons use are especially inefficient to start with, and so they're usually designed to cool heavily, with fans and fins. The heat you feel coming out the back of the microwave is NOT heat from the food, it's the waste heat off the magnetron. Adding too much to that waste heat can overheat and damage the magnetron, sometimes very quickly.
So, if you put a substantial chunk of metal into a tuned cavity like a microwave oven, it will interfere with the transfer of energy and cause a higher SWR, which can damage the magnetron. Running a microwave without anything in it is not recommended for the above reason, but adding metal into the mix makes matters worse. Placing nothing in the cavity besides a substantial piece of metal is about as destructive as you can be. The denser the metal, the bigger the effect.
I work for the Department of Redundancy Department.
Github, Reddit,^H^H^H^H^H^H^H Slashdot... the sewer is overflowing.
To understand recursion, you must first understand recursion.
I have seen lives ruined this way - be careful out there.
sheep.horse - does not contain information on sheep or horses.