Impaired-driver sensor could pave the way for safer vehicles

Date:
December 8, 2021
Source:
American Chemical Society
Summary:
The bipartisan infrastructure bill recently signed into law
by President Joe Biden includes a requirement for automakers
to install driver monitoring systems that detect intoxicated
or impaired drivers. Current systems rely on cameras, which
have limitations. Now, researchers have made heat-resistant,
pressure-detecting sensors that, when attached to seats, can tell
whether a driver is drowsy or has a sudden illness, signaling a
future smart car to take action.



FULL STORY ==========================================================================
The bipartisan infrastructure bill recently signed into law by President
Joe Biden includes a requirement for automakers to install driver
monitoring systems that detect intoxicated or impaired drivers. Current
systems rely on cameras, which have limitations. Now, researchers
reporting in ACS Applied Electronic Materials have made heat-resistant, pressure-detecting sensors that, when attached to seats, can tell whether
a driver is drowsy or has a sudden illness, signaling a future smart
car to take action.


==========================================================================
Most current drowsiness detection systems use an exterior, forward-looking camera to monitor lane position or sudden, exaggerated corrections. Others
use an interior camera to check a driver's face or eyes for signs of
nodding off.

Camera-based systems, while useful, have drawbacks. For example, an
exterior camera could be blocked by mud, and an interior camera could
be less effective at night. Scientists have previously explored using piezoelectric sensors - - self-powered materials that accumulate an
electrical charge in response to pressure -- for monitoring a driver's
posture, which changes when a person falls asleep, has a sudden health emergency or is intoxicated. However, existing piezoelectric sensors
cannot withstand high temperatures, a requirement for electrical and
electronic equipment in vehicles. Toshimi Nagase and colleagues wanted
to develop flexible, heat-resistant piezoelectric sheet sensors that
could be embedded in a vehicle's seat to monitor the driver's posture.

The researchers prepared zinc oxide-based films directly on a polyimide
surface and then screen-printed a silver paste on both sides to obtain a piezoelectric sheet. They connected a coaxial cable to detect changes in electrical charge with pressure and then folded the sheet in half around
the cable. The sensor sheet resisted heating up to 250 F, with no changes
in its properties. After showing that the sensor could discriminate
changes in mechanical load, the team placed a sensor in the back of a
chair. By detecting a seated person's slight body movements, the sensor
allowed the researchers to calculate the person's respiration and pulse
rates. Two other sensors attached to the seat of a chair could sense
when a person leaned left or right with their upper body, which could
indicate drowsiness.

The researchers say that in the future, a monitoring system based
on the sensors might detect changes in vital signs or body posture,
triggering a self- driving car to find a safe location and then stop. The vehicle could also contact emergency healthcare providers, depending
on the situation. To get to that point, the next step is to test the piezoelectric sensors in a car, where vehicle motions and vibrations
will contribute to background noise in the measurements, the team says.

========================================================================== Story Source: Materials provided by American_Chemical_Society. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Toshimi Nagase, Kazuhiro Nonaka, Yasutake Koishi, Shuichi Ishida,
Tatsuo
Tabaru, Yasushi Sato. Heat-Resistant, Flexible Piezoelectric Sheet
Sensors Based on Solution-Processed Zinc Oxide Films for In-Vehicle
Driver Monitoring Applications. ACS Applied Electronic Materials,
2021; 3 (11): 4743 DOI: 10.1021/acsaelm.1c00603 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211208090119.htm

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