Tag Archives: accelerometer

Your smartphone can tell when you’re drunk — and this might save lives

Credit: Pixabay.

Not everyone gets intoxicated from drinking the same amount of alcohol. Some feel tipsy after a single drink while other, more experienced, bar-hoppers can go shot after shot and still keep a straight face. However, once a person truly becomes intoxicated, it’s hard to keep it a secret — especially if you have to walk from point A to point B.

In a new study, researchers at Stanford University and the University of Pittsburgh have used smartphone built-in hardware to identify ‘drunken gaits’ with up to 92% accuracy. In the future, an app may be able to send notifications to intoxicated users that it is unsafe to drive or that they should be more careful in public, potentially saving lives.

The walk that doesn’t lie

The fact that a person’s gait can be tied to their level of alcohol toxicity is by no means a novelty. Police officers routinely employ so-called field sobriety tests to determine if a person suspected of impaired driving is intoxicated with alcohol.

The gait sobriety test has now been integrated into a smartphone, whose accelerometer can determine if a person is walking ‘funny’.

For their study, the researchers recruited 17 volunteers (12 male and 5 female) and served them vodka cocktails (for science!). After an hour of drinking their first serving, the participants had to complete a walking trial consisting of 10 steps forward and 10 steps backward every hour for seven hours. During this entire time, their smartphones were strapped to their lower backs, which is where the accelerometer can most accurately determine a person’s gait.

Their height and weight were also measured in order to determine how much alcohol would be required to intoxicate them — this is equivalent to a breath alcohol concentration (BrAC) of 0.08. Speaking to Inverse, lead study author Brian Suffoleto says that one shot of vodka raises the blood alcohol concentration (BAC) by 0.02 for men and by 0.03 for women.

The smartphone accelerometer recorded lateral movement corresponding to a back-and-forth swaying motion, which is a key sign of intoxication. Based on this recorded motion, the researchers could determine if a person’s BrAC was above 0.08 with 92% accuracy.

As an important caveat, these results are valid in a highly controlled research environment. In the real world, people’s gaits will naturally vary much more as they move around obstacles or in a crowded environment like a bar. Also, people don’t wear their smartphones on their backs, although Suffoleto says that they can adapt their analysis algorithms to data recorded from the trouser’s pocket.

The biggest challenge, according to Suffoleto, is designing a communication strategy that might convince a person impaired with alcohol to respond positively to supportive messaging.

In order to reduce alcohol-related traffic accidents and deaths, some have previously proposed embedding breath analyzers inside vehicles. If the exhaled breath contains alcohol levels past a legal threshold, the car won’t start. However, this is unrealistic, says Suffoleto — at least in the U.S. where consumers would not purchase a vehicle that would lock them out of their own property.

But that doesn’t mean there aren’t more persuasive methods. Suffoleto envisions a system where people can pay significantly less for their car insurance as long as they agree to this sort of monitoring.

The findings appeared in the Journal of Studies on Alcohol and Drugs.

Close-up of the 'quantum compass'. Credit: Imperial College London

‘Quantum compass’ can locate objects without GPS

It’s difficult to imagine modern life without GPS — we use it for everything from personal and in-car navigation, to drones and self-driving cars. Sometimes, however, a GPS signal might not be available due to factors such as tall buildings, lack of signal, or deliberate jamming by a third party. Now, British researchers at Imperial College London (ICL) have presented an alternative to the time-honored GPS, a quantum “compass” that can pinpoint its location on the globe without having to rely on satellites or any other external reference.

Close-up of the 'quantum compass'. Credit: Imperial College London

Close-up of the ‘quantum compass’. Credit: Imperial College London

The remarkable device was recently unveiled at the National Quantum Technologies Showcase, an event dedicated to presenting the technical progress achieved by projects funded by the UK National Quantum Technologies Programme, worth £270m.

Credit: Imperial College London.

Credit: Imperial College London.

The researchers who built the device call it a “standalone quantum accelerometer”. Today, accelerometers are commonly embedded in all sorts of common technologies, including airbags or your phone. As the name implies, accelerometers are electromechanical devices that sense either static or dynamic forces of acceleration to keep track of the movement and orientation. Using an accelerometer, it’s easy to determine the position of an object knowing its original position and velocity. However, over time, a regular accelerometer loses precision without an external reference, such as a GPS signal, to calibrate it.

This new quantum accelerometer doesn’t have this problem, being able to accurately measure its position without any external reference. It is, for all intents and purposes, self-contained.

What sets the ICL technology apart from other accelerometers is that it measures the properties of supercooled atoms. Close to absolute zero, the movement of atoms starts exhibiting quantum behavior, acting as both particles and waves. Because the wave properties are affected by acceleration, an ‘optical ruler’ can measure extremely minute changes with accuracy. The atoms are both cooled and measured by a laser system.

“When the atoms are ultra-cold we have to use quantum mechanics to describe how they move, and this allows us to make what we call an atom interferometer,” Dr. Joseph Cotter, from the Centre for Cold Matter at Imperial, said in a statement.

As it stands today, the quantum compass is far too large to fit inside a phone, but it could prove useful for the navigation of ships or trains. However, since the principles are the same, the device could also be suitable for research in fundamental science such as the search for dark energy or detecting gravitational waves. Military applications will also find quantum compasses incredibly appealing since a nuclear submarine or airplane can now precisely track its position without having to rely on GPS, whose signal is both detectable and jammable.

Having an alternative to GPS will certainly come in handy. According to an estimate, if the satellite network was denied for a single day, the UK would stand to lose about a million pounds. This is just the beginning, though — we should all expect more interesting things to come out of such a technology.

“I think it’s tremendously exciting that this quantum technology is now moving out of the basic science lab and being applied to problems in the wider world, all from the fantastic sensitivity and reliability that you can only get from these quantum systems,” Professor Ed Hinds, from the Centre for Cold Matter at Imperial, said in a statement.

The results are promising, but are still in an early stage, and have not been peer-reviewed. It remains to be seen whether the results really stand true, and whether the technology could be incorporated into practical situations. At least for now, the jury is still out on this one.