Battery-Free Smart Sock for Abnormal Relative Plantar Pressure Monitoring

This paper presents a new design of a wearable plantar pressure monitoring system in the form of a smart sock for sensing abnormal relative pressure changes. One advantage of this approach is that with a battery-free design, this system can be powered solely by radio frequency (RF) energy harvested from a radio frequency identification (RFID) reader unit hosted on a smartphone of the wearer. At the same time, this RFID reader can read foot pressure values from an embedded sensor-tag in the sock. A pressure sensing matrix made of conductive fabric and flexible piezo-resistive material is integrated into the sock during the knitting process. Sensed foot pressures are digitized and stored in the memory of a sensor-tag, thus allowing relative foot pressure values to be tracked. The control unit of the smart sock is assembled on a flexible printed circuit board (FPC) that can be strapped to the lower limb and detached easily when it is not in use. Experiments show that the system can operate reliably in both tasks of RF energy harvesting and pressure measurement.

[1]  Apurba Das,et al.  Process control in textile manufacturing , 2013 .

[2]  L. Lavery,et al.  Effectiveness of the diabetic foot risk classification system of the International Working Group on the Diabetic Foot. , 2001, Diabetes care.

[3]  Kin-Lu Wong,et al.  Characteristics of a 2.4‐GHz compact shorted patch antenna in close proximity to a lossy medium , 2005 .

[4]  G Gravante,et al.  Comparison of ground reaction forces between obese and control young adults during quiet standing on a baropodometric platform. , 2003, Clinical biomechanics.

[5]  Rezaul K. Begg,et al.  Foot Plantar Pressure Measurement System: A Review , 2012, Sensors.

[6]  M Lord,et al.  Foot pressure measurement: a review of methodology. , 1981, Journal of biomedical engineering.

[7]  Xiaoyou Lin,et al.  A Linear Wide-Range Textile Pressure Sensor Integrally Embedded in Regular Fabric , 2015, IEEE Sensors Journal.

[8]  Lanlin Z. Lee,et al.  Embroidered Multiband Body-Worn Antenna for GSM/PCS/WLAN Communications , 2014, IEEE Transactions on Antennas and Propagation.

[9]  Syed Mahfuzul Aziz,et al.  Identification of Foot Pathologies Based on Plantar Pressure Asymmetry , 2015, Sensors.

[10]  Yohan Payan,et al.  Smart Diabetic Socks: Embedded device for diabetic foot prevention , 2014, 1404.3993.

[11]  Qiao Li,et al.  In-Shoe Plantar Pressure Measurement and Analysis System Based on Fabric Pressure Sensing Array , 2010, IEEE Transactions on Information Technology in Biomedicine.

[12]  Comparison of static plantar foot pressure between healthy subjects and patients with adolescent idiopathic scoliosis , 2014, Toxicology and Environmental Health Sciences.

[13]  M. van der Leeden,et al.  Forefoot joint damage, pain and disability in rheumatoid arthritis patients with foot complaints: the role of plantar pressure and gait characteristics. , 2006 .

[14]  U. Kanatlı,et al.  Evaluation of the transverse metatarsal arch of the foot with gait analysis , 2003, Archives of Orthopaedic and Trauma Surgery.

[15]  J. Dargahi,et al.  A New Approach for Modeling Piezoresistive Force Sensors Based on Semiconductive Polymer Composites , 2012, IEEE/ASME Transactions on Mechatronics.

[16]  S. Curto,et al.  DETUNING STUDY OF IMPLANTABLE ANTENNAS INSIDE THE HUMAN BODY , 2012 .

[17]  S Ino,et al.  An in-shoe device to measure plantar pressure during daily human activity. , 2011, Medical engineering & physics.

[18]  Shuvo Roy,et al.  A Wearable Patch to Enable Long-Term Monitoring of Environmental, Activity and Hemodynamics Variables , 2016, IEEE Transactions on Biomedical Circuits and Systems.

[19]  M. Manteghi,et al.  Performance of an Implanted Electrically Coupled Loop Antenna inside Human Body , 2014 .

[20]  K A Athanasiou,et al.  Is there a critical level of plantar foot pressure to identify patients at risk for neuropathic foot ulceration? , 1998, The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons.

[21]  R. W. Lau,et al.  The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz. , 1996, Physics in medicine and biology.

[22]  R M Stess,et al.  The Role of Dynamic Plantar Pressures in Diabetic Foot Ulcers , 1997, Diabetes Care.

[23]  M. Cornwall,et al.  The distribution of plantar pressures in American Indians with diabetes mellitus. , 2001, Journal of the American Podiatric Medical Association.

[24]  D. Rosenbaum,et al.  Plantar Pressure Distribution Patterns of Young School Children in Comparison to Adults , 1994, Foot & ankle international.