Wearable strain sensors for patient monitoring

In-hospital and at-home patient monitoring is booming. Research company IDTechEx predicts the wearable technology market will reach more than $40 billion in 2018, then growth will accelerate to 23% annually to $100 billion by 2023 and $150 billion by 2026. The reason is obvious – more data means more information to analyze for better diagnoses.

“Today, [doctors] are only using one or two, costly, power-hungry sensors to measure certain things. And they only use them if they must, to collect the most critical information. They really want to gather more information from several points to understand more holistically what’s happening to the patient,” explains Mario Calvo, business unit manager of the Quick Coupling Division at Parker Hannifin.

To address this, Parker Hannifin is improving a cost-effective, hyper-elastic electroactive polymer (EAP) Senso- NODE strain sensor. Parker acquired the technology from Bayer Material Science in 2014 and the company has been developing the sensor since then. The device features a stretchable conductor that maintains conductivity when stretched 100%.

Components

EAP exhibits a change in size or shape when stimulated by an electric field. The field generates coulomb attractive forces on the electrodes which apply compressive forces on the dielectric changing the size or shape. Two screen-printed materials sandwich the sensor on the top and bottom. Low power is applied, and when the material is stretched, the device measures the change in capacity.

Parker’s dielectric SensoNODE uses primarily silicone dielectric film, carbon ink electrodes, and epoxy frame material. SensoNODE can be used to create a variety of devices including sensors, actuators, and energy harvesting devices.

“What is important is that it becomes a capacitor and you can measure very small changes in shape,” Calvo says. “And there’s nothing out there today that can really wrap around surfaces. As you move you can monitor and measure that change in movement.”

IIoT

Parker offers its SensoNODE sensor with SCOUT Mobile software for advanced condition monitoring. Parker’s approach creates new possibilities with industrial internet of things (IIoT)-enabled assets, delivering predictive analytics that drive tactical, operational, and strategic decisions, leading to maximum uptime.

Wireless connectivity allows access to real-time and historical data for a comprehensive picture of system performance.

“In some cases, we are taking what we know with the IIoT and partnering up with a medical device company. They may use what we have and maybe rebrand it. Other times we are giving them our know-how through a licensing agreement and showing them how to use that data. And sometimes, companies have all of this in house so they need to collect more information through our services,” Calvo explains. “If [doctors] can send [patients] away with a device that they can wear comfortably, doctors can look at the data prior to the patient returning to better assess the patient and walk through the data from when they were away.”

Parker Hannifin Corp.
www.parker.com