Ordinary CD players to monitor our health?: "Many of us, at least in developed countries, have CD players rusting in our homes. So why not turning them into something useful? A very short note by the American Chemical Society (ACS) says that Spanish researchers have adapted this now venerable technology into home health monitoring systems. This means that CD technology could be used for tests ranging from the measurement of environmental toxins to at-home disease diagnosis and even laboratory-based testing."
"The set of servo systems (spindle and stepper motors) of the CD drive keeps the laser beam focused on the spiral track, allowing disc rotation and laser scanning. The transmitted light through the disc is transformed by the photodiode into an analog electrical signal. At the same time, the photosensor detects the trigger footprints, starting the data collection on disc. [...] The CD drive is controlled by software and connected to the computer by USB2.0 interface." You also can see a picture of the CD player used in this work (B). (Credit: Universidad Politecnica de Valencia, Spain)