Advancing Strain Sensing with Electrical Impedance Tomography

Stretchable strain sensors are devices designed to measure deformation or strain while being able to stretch and conform to curved or flexible surfaces. They are important because they enable new applications in wearable technology, soft robotics, healthcare monitoring, and human-machine interfaces, where traditional rigid sensors cannot be used.

 Key challenges include:

• Achieving high sensitivity and accuracy while maintaining stretchability.
• Minimizing the impact of the sensor on the mechanical properties of the material being measured.
• Ensuring long-term stability and durability under repeated stretching and bending.
• Developing cost-effective and scalable manufacturing methods.
• Reducing signal noise from cross-talk between electrodes

Common materials include:

• Elastomers (such as silicones and polyurethanes) to provide stretchability.
• Conductive fillers (such as carbon black, carbon nanotubes, silver nanowires, and conductive polymers) to enable strain-dependent electrical conductivity.
• Conductive textiles and stretchable electrodes for connecting the sensor to measurement electronics.

Spatially resolved strain sensing allows for a more detailed understanding of deformation patterns, enabling:

• More precise control of soft robots through feedback from multiple sensing points.
• Enhanced gesture recognition and motion tracking in wearable devices.
• Improved monitoring of joint movement and muscle activity in healthcare applications.
• Better understanding of the mechanical behavior of soft materials.

Grid-based soft sensors simplify data acquisition but require advanced multiplexing to reduce crosstalk. These sensors have a limited resolution. It’s also important to account for the varying properties of these sensors.

Key metrics include:

• Sensitivity (Gauge Factor): How much the sensor’s resistance changes per unit of strain.
• Linearity: How linear the relationship is between strain and resistance change.
• Hysteresis: The difference in output for a given strain value depending on whether the strain is increasing or decreasing.
• Stretchability: The maximum strain the sensor can withstand without failure.
• Durability: The number of stretch-release cycles the sensor can endure before performance degrades.
• Response Time: How quickly the sensor responds to changes in strain.

The Volume of Tissue Activated (VTA) refers to the region of brain tissue that is directly affected by the electrical stimulation from the DBS electrode. Accurately predicting the VTA is crucial for optimizing DBS parameters to maximize therapeutic benefits and minimize side effects.

Wearable devices require precise, real-time EDA tracking to provide meaningful insights into stress, emotions, and mental well-being. Multi-frequency impedance measurement enables: 

✔ More accurate stress quantification in real-world settings 

✔ Differentiation between emotional responses & external factors 

✔ Continuous monitoring for long-term mental health applications 

💡 Sciospec’s ISX-3 is designed to support advanced impedance measurement in wearable research and stress monitoring applications.