Motion measurement strain sensors have many uses, such as tracking a person’s physical activity or reading blood pressure. Such new devices may prove particularly useful because they combine high sensitivity with a wide range of detectable motion.
Strain sensors typically work by measuring the change in current caused by some movement stretching the sensor. Most of them are optimized to be extremely sensitive to even the smallest movements. Also Enables motion detection over a wide physical range.
In other words, one sensor may be good at detecting very small movements, but can only extend a few millimeters, while another sensor may miss such small movements, but up to a few millimeters. Large movements can be detected while being stretched. inch.
Based on previous research, Dr. Yong Zhu and colleagues at North Carolina State University set out to create sensors that do not sacrifice one function for the other.
The resulting device takes the form of an elastomeric polymer strip embedded with a network of conductive silver nanowires. A series of parallel cuts are made halfway down the side of the sensor, alternating between left and right sides. When the sensor is in its relaxed state, the current through the sensor can pass through the cut.
However, when the sensor is stretched or twisted, these notches become gaps, forming a zigzag pattern. This property allows the device to be stretched much longer than other methods without damaging it.
At the same time, the current can no longer flow straight from one side of each cut to the other, forcing it to follow longer routes in a zigzag pattern like a slalom skier.The electrical resistance increases accordingly and depending on how you measure many When increased, even the slightest stretch/movement can be detected.
Shuan Wu
In the tests conducted so far, this technology has been used to a high degree. sensitive wearable blood pressure measurement device, Elastic A device that monitors the movement of a person’s back, and a three-dimensional touch-sensitive controller that can be used to play video games.
“Sensors can be easily integrated into existing wearable materials such as fabrics and exercise tapes, making them useful for practical applications,” said Zhu. “And all of this is just superficial. I think there are a variety of additional applications as we continue to work with this technology.”
A paper on this study was recently published in the journal ACS Applied Materials & Interfaces.
Source: North Carolina State University
