Highly Sensitive Mechano optical Strain Sensor for Human Gaits monitoring and high end Robotic Applications

Nowadays the field of flexible and soft electronics has captured a great level of researchers. This technology has introduced various wearable and skin mountable devices that have successfully achieved conformal interaction with the human body and long term monitoring capabilities. With the help of

Project Title

Highly Sensitive Mechano optical Strain Sensor for Human Gaits monitoring and high end Robotic Applications

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

Nowadays the field of flexible and soft electronics has captured a great level of researchers. This technology has introduced various wearable and skin mountable devices that have successfully achieved conformal interaction with the human body and long term monitoring capabilities. With the help of these small-size wearable devices, the complex maneuverability of the human body can be easily monitored with acceptable accuracy, simplicity, and minimum discomfort. Some innovative sensors are strain sensor, pressure sensor, temperature sensor, force sensor etc. Recently different kinds of wearable strain sensors are proposed by using several nanomaterials bounded with highly flexible and stretchable polymers. Nanomaterials are utilized due to their outstanding electrical, mechanical, chemical properties while polymer ensures the flexibility, support materials and both provide the stretchability and flexibility. In this work, we are going to design an ultra-flexible mechano- optical strain sensor that achieves both, the sensitivity (to minutes changes to applied strain) and multi-directional flexibility which ensures high gauge factor, better reproducibility, and less memory effect. This will be made possible using a new method of exploiting the optical properties of nano- composite. We name our proposed sensing device as a mechano-optical strain sensor. In this phenomenon, the transmittance of 2D nanomaterials (MoS2) will be modulated with the applied   tensile strain; light falls on Photo Detector and light falling totally depends on the variations in the transparency of nanomaterials which detects the change in current. Ecoflex will be used as a matrix material (which can bear stretchability of up to 1000%) for supporting stretchability and Molybdenum Disulphide (MoS2) with DMF (Dimethylformamide solvent) mixed together in order to obtain nanomaterial. The dispersion of 2D material will be sprayed on the PET substrated which will then be transferred to the semi-cured ECOFLEX. This will be lead to the integration of nanoparticles inside   the matrix. Here our main consideration is strain sensor because of its broad applications in health monitoring, human motion detection, soft robotics and so on.

We will use this sensor in the biomedical applications by continuously monitoring the status of any paralyzed subject body by simply adhering the as-developed sensor on different parts of the body (like shoulder, fingers, abdomen, neck etc.) Similarly, monitoring the performance of sportsman can also be performed easily. Besides this, the signal from the strain sensor can be utilized to actuate soft robots.

Project Objectives

• To design a highly sensitive mechano-optical strain sensor based on optical transmittance change using simple and cost-effective principle.
• Sensor’s electrical, mechanical and electrochemical characterizations will be performed.
• The applications like health monitoring (simple, precise and accurate measurement) and robotics feedback will be demonstrated.

Project Implementation Method

In this work we will prepare flexible wearable strain sensor through two different techniques for comparison and observing the robustness of efficient method for further implementation of work:

(1) Molding and casting method with the help of 3D printing mold cases for preparation of substrate. With this method we obtain our polymer of different dimensions by molding it in different sizes of casing.

(2) Spin coating technique for the preparation of substrate. By using spin coater machine we obtain our polymer with different level of layers and this can be obtained by controlling the RPM of spin coater machine. More RPM provides a thinner substrate of polymer and vice versa.

However, different samples of proposed flexible strain sensors will also be prepared varying in thicknesses and material composition, in order to select the best sample for practical implementation. All these samples varying in thicknesses and material compositions will be prepared through both said methods.

Benefits of the Project

1. In Biomedical side, wearable highly flexible mechano-optical strain sensors gathered the physical data from human body and transmit the data from wearable sensor to mobile phone or an access point. So paralyzed people don’t need to visit hospital for checkup on daily basis and can do that by themselves in their homes.
2. Skin-mountable and wearable mechano-optical strain sensors can function for the sport performance monitoring by mounting them in different parts of the body. The output signal of skin-mountable strain sensors attached to the wrist and elbow. The sensory information can be used for the body movement analysis during sport activities.
3. In robotics side the signal from strain sensor can be utilized to actuate smart robots. These strain sensors were attached to the fingers of gloves for the bending angle measurement of finger joints. The information of sensors was wirelessly transferred from smart glove to the gripper robot. Bending and straightening of fingers was utilized to control the robot for performing different tasks.
4. Skin-mountable and wearable mechano-optical strain sensors can be utilized as motion sensors and input gears for virtual reality. This can also be used for medical training, home-rehabilitation, and therapy applications. 

Technical Details of Final Deliverable

The final product of the proposed project will be flexible wearable opto-mechanical strain sensors. The proposed device will be prepared using simple casting-molding technique. The casting molds will be prepared by using 3D printing machines. After fabrication of the proposed device, we will use these devices in various health monitoring applications. Regarding the health monitoring applications, we will prepared a gadget consist of as-developed flexible sensors and wireless electronic circuitry for monitoring the movement of differtent human gaits and collecting data for analysis. 

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Health

Other Industries

Medical

Core Technology

Wearables and Implantables

Other Technologies

Artificial Intelligence(AI), Internet of Things (IoT), Clean Tech

Sustainable Development Goals

Good Health and Well-Being for People

Required Resources

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