The stethoscope, invented 200 years ago because a French doctor was too embarrassed to put his ear directly against a woman's chest, is finally getting a digital upgrade. A device called the Eko Core, which attaches to a regular stethoscope, has just been approved for medical use by the US FDA. It amplifies and records the sound signals transmitted by the ubiquitous medical devices, then sends the sound waves wirelessly to an iPhone app. From there, doctors can record the waveform and either listen to it later or compare it to a future visit to test the effects of a treatment. It will also be handy as a teaching too for medical students.