With a new sort of sensor – a pencil drawing — it may soon be possible to detect hydration levels, breathing changes, and a soiled diaper. Researchers at Pennsylvania State University in the United States have created a method to monitor humidity and respiration by sketching a circuit board-like design on pre-treated paper.
As per CTV News, this artwork can send signals to your smartphone and has already been utilized to make a “smart diaper” capable of alerting parents to a baby’s discomfort.
Researchers believe that the sensor might be used in the future to monitor not only for a full diaper but also for health issues such as cardiac arrest and pneumonia, as well as for switches that do not require physical contact.
In a press release, Huanyu “Larry” Cheng, James L. Henderson, Jr. Memorial Associate Professor of Engineering Science and Mechanics at Penn State and lead author of a new study about the research, said, “Our team has been focused on developing devices that can capture vital information for human health.” The purpose of early disease and health status prediction is to identify problems before it is too late.
A report published in December in the peer-reviewed journal Nano Letters details the sensor’s operation and early applications examined by scientists. Researchers revealed that the sensor is generated by drawing with a pencil on sodium chloride-treated paper.
As water molecules from the surrounding environment absorb into the paper and combine with the sodium chloride solution, the solution becomes ionized, and electrons begin to flow through the graphite of the pencil marks.
Utilized in computers and other electronic equipment, printed circuit boards consist of copper lines arranged in precise geometric designs. Copper is utilized as a conduit for electrical information to move through, and researchers are reproducing this technique, but this circuit board is built out in pencil rather than copper.
Using copper wires and conductive silver paste, the paper sensor may be connected to a computer, or it can be attached to a tiny lithium battery and used to interact wirelessly with a smartphone.
The sensor can transmit a signal to a smartphone that causes the smartphone’s screen to display humidity data. According to researchers, it can deliver reliable readings for humidity levels ranging from 5.6% to 90%.
The concept of wearable sensors is not new; current flexible humidity sensors play a significant role in modern health care, including respiratory monitoring and detection of skin humidity. However, it is difficult to get great sensitivity at a lower price point, limiting the accessibility of these sensors.
At a press release, Li Yang, a professor in the School of Artificial Intelligence at China’s Hebei University of Technology, said, “We wanted to design something low-cost that people could grasp how to make and use, and nothing is more accessible than pencil and paper.” “A multimillion-dollar piece of machinery is not required for manufacture. Simply be able to write inside the lines of a pre-drawn electrode on a piece of treated paper. It can be accomplished easily and rapidly.”
Four humidity sensors were layered between the absorbent layers of a diaper to develop a prototype of a “smart diaper” that could detect moisture and notify the need for a change. Cheng stated that the inspiration for this application of the sensor originated from his own experience with his two small children.
“There is no simple method to determine how wet is wet, and this knowledge might be quite useful for parents,” he said. “The sensor can offer short-term data to notify for diaper changes, as well as long-term data to reveal patterns that can tell parents about their child’s overall health.”
Researchers also tried a respiratory monitor version by painting the sensor directly onto a face mask coated with a solution. Through the sensor, they were able to distinguish between mouth and nose breathing, and the sensor could detect three distinct types of breathing: deep, regular, and quick.
This type of data may be utilized to inform medical workers if a patient suddenly experienced difficulty breathing or to detect the onset of a variety of respiratory illnesses. When applied to the task of skin hydration, the sensor was able to identify the underlying humidity of human skin, regardless of whether the patient had recently exercised or applied lotion.
Cheng stated, “Different sorts of illness conditions result in varying rates of water loss from the skin.” “The skin will operate differently depending on these underlying circumstances, which we will be able to identify and maybe define using the sensor.”
According to researchers, the applications for this form of sensor are vast. It can even be used as a non-contact switch, with the sensor able to detect the presence of a finger hovering above it by measuring the change in air humidity.
Cheng explained, “The atoms on the finger do not need to touch the button in order to disseminate the water molecules and activate the signal.” Considering what we’ve learned during the pandemic about the need to minimize the body’s contact with common surfaces, a sensor like this could be a valuable tool for preventing potential contamination.
Researchers conducted a few experiments using the sensor to evaluate this application. They discovered that by hovering their finger over the sensor, they could raise a miniature elevator, illuminate LEDs, and play keyboard notes.
It is unknown how soon we will see smart diapers and smart face masks on store shelves, but researchers are hopeful that this could lead to medical advancements.
