Plenty of devices exist to tell you whether or not you have bad breath, and new ones are being invented all the time. Consider a recent report published in the journal Sensors and Actuators B: Chemical, in which researchers described the creation of a contraption that uses crystals and sound waves to pinpoint halitosis.
While the underlying mechanism is pretty complex - as you might imagine, from such a dry-sounding journal - the device basically consists of an acoustic wave sensor, a chemically coated piezoelectric crystal and a tube cooled by liquid nitrogen.
The creators said that a patient simply blows into the tube, which collects their breath, freezes out the water vapor, passes the air over the crystal and detects the oscillations made by the compounds in the gases.
The team tested the device on a number of volunteers, and found that it was especially accurate at detecting bad breath in people with chronic periodontal disease, a serious infection of the gums and dental roots that cause a powerful oral stink.
While the innovation is exciting, why wait to try it? It may be better to assume you have halitosis and act accordingly - namely, by looking into a good specialty breath freshener.