When a scientist become a hacker.
Posted by awqi_zar on Sep 29, 2007 in Teknologi • 1 commentSekumpulan penyelidik daripada Sepanyol telah berjaya mengubah pemain CD pada komputer anda menjadi pengesan(scanner).Dengan berbekalkan dua lampu pengesan tambahan yang diletakkan di dalam pemain CD itu dan juga perisian yang telah diubahsuai.
Pemain CD yang telah diubah-suai itu dapat mengesan pestisid dalam jumlah yang terlalu kecil yang diletakkan di bahagian atas CD biasa.
Modified CD player.
Maquieira and colleagues soldered two extra light sensors inside a CD player, and used software to control the way the device “plays” a disk.
The first sensor identifies the sector of a disk containing a sample using black marks on the edge of the disk. The second analyses the sample itself, measuring the amount of laser light that is able to pass through the disk. The off-the-shelf disks used normally reflect around 30% of the laser beam onto the reading head, with the rest passing through.
In experiments, the researchers used their modified drive to detect traces of three different pesticides. A sample – half a millimetre across on a disk – was treated normally, using a set of reactions that produce an amount of dye or silver that is inversely proportional to the amount of pesticide in the sample.
The amount of laser light that passed through the disk to the second sensor indicated the levels of dye or silver. The modified drive was thus able to detect levels of pesticide as low as 0.02 micrograms per litre.
Although the hacked device lags behind the performance of specialised machines, it is accurate enough for many lab tasks, the team says.
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