Now your CD player will not only play music but also can be converted into a highly accurate scanner for chemical or medical tests. Spanish researchers have shown that by soldering two additional light sensors to a normal CD or DVD drive one can detect tiny quantities of pesticide in samples placed on top of an the compact disk. The first sensor identifies the sector of a disk containing a sample using black marks on the edge of the disk while the second investigates the sample itself, measuring the amount of laser light that is able to pass through the disk. The laboratory machine has to accurately scan samples with light and record the results; a CD player uses similar precision to read the tiny pits that encode music or data on a disk. The main benefits of using a CD reader are it is simple, ease to operate, portable and versatile to use.

The machines used for light detection are expensive, normally costing between 30,000 and 60,000 euros as compared to the CD drive.
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