Development on portable ‘electronic noses’ that can fit inside a smartphone could open up new horizons for health, food, personal hygiene and even security, but the technology sector is struggling to create a workable device with this capability.
Redg Snodgrass, a venture capitalist that funds hardware start-ups, outlines many possibilities the technology could offer.
It could allow phones to analyse what someone has eaten or drunk based on the chemicals they emit, detect disease early via an app, or smell the fear in a potential terrorist. "Smell," he says, "is an important piece" of the puzzle.
Yet the history of electronic smelling technology is littered with aborted projects and failed companies, although that has not stopped newcomers from trying.
The Grenoble-based Aryballe Technologies recently showed off a prototype of NeOse, a handheld device that can initially detect up to 50 common odours.
David Edwards, a chemical engineer at Harvard University, believes there could be a problem with such devices, as scent is not energy like light and sound, but is mass. "It's a very different kind of signal," he said.
That means each smell requires a different kind of sensor, making devices bulky and limited in what they can do. The aroma of coffee, for example, consists of more than 600 components.
France's Alpha MOS was first to build electronic noses for limited industrial use, but its foray into developing a smaller model that would do more has run aground.
Within a year of unveiling a prototype for a device that would allow smartphones to detect and analyse smells, the website of its US-based arm Boyd Sense has gone dark. Neither company responded to emails requesting comment.
The website of Adamant Technologies, which in 2013 promised a device that would wirelessly connect to smartphones and measure a user's health from their breath, has also gone quiet. Its founder didn't respond to emails seeking comment.
For now, start-ups focus on narrower goals or on industries that don't care about portability.
California-based Aromyx, for example, is working with major food companies to help them capture a digital profile for every odour, using its EssenceChip. By waving some food across the device, it captures a digital signature that can be manipulated as if it were a sound or image file.
Yet despite its name, this is not being done on silicon, says CEO Chris Hanson. Nor is the device something you could carry or wear. "Mobile and wearable are a decade away at least," he said.
Partly the problem is that we still do not properly understand how humans and animals detect and interpret smells. The Nobel prize for understanding the principles of olfaction, or smell, was awarded only 12 years ago.
"The biology of olfaction is still a frontier of science, very connected to the frontier of neuroscience," Edwards said.