Smart wearable sensing platform with wireless communication and embedded processing for health monitoring applications
Authors: AitMou Younss , Elgendy Menatollah , Jan Safiya , Lucas Augusto Manuel , Elzein Almiqdad , Bermak Amine 
Published: June 2019

Diabetic patients tend to develop plantar ulcers due to various factors related to their pathology. These factors include, but are not limited to, a lack of plantar sensation, a poor blood circulation, and feet deformities. The plantar ulcers can be managed and cured if detected at an early stage and appropriately treated. However, if not detected early, they can evolve to rich critical stages involving extreme curative strategies such as amputation. Accordingly, it is crucial to detect these ulcers at an early stage. A common strategy to prevent ulcers worsening is by increasing the patient's medical check frequency. Although beneficial, this therapeutic approach is time consuming and might not be a perfect solution for elderly patients, and patients with reduced locomotive abilities. Accordingly, various groups have oriented their work toward the development of smart shoes to monitor plantar physical parameters under various conditions [1-3]. Previous studies have focused on healthy foot pressure analysis and soft therapies. Moreover, none of these studies has developed a centralized data system. Accordingly, our present work aim to develop a user and mobile phone friendly wireless device that is specifically targeting patients with diabetes to prevent plantar ulcers from reaching the critical levels by early detection of peak pressure, temperature, and humidity. Moreover, to improve patient monitoring, collected data will be centralized in a global database. To the aim of our present work we employed Velostat (a.k.a. Linqstat) to acquire plantar pressure. Velostat is thin conductive material that was previously employed as pressure sensor. When combined with an array of conductive net, this material can act as an array of pressure-sensors. Accordingly, we built a 10 cell array to acquire pressure from 10 strategic plantar locations, namely: Medial Plantar; Lateral Plantar; Saphenous; Sural; Tibial. Plantar wounds are often associated with increased local temperature that reflects a local sub-dermal infection. To monitor the temperature alteration, we utilized a DHT11 module. The DHT11, is an ideal module for simultaneous measurement of both temperature and humidity. Wound infection is often accompanied by local swelling and bleeding, Hence, the humidity detection. To acquire and pre-process the raw data, we employed an ATMEL 8-bit Microcontroller (ATMEGA 2560). Given it's high pin count, this device allowed as to overcome adding multiplexers to handle the significant number of input signals (13). Thus, allowing us to reduce the prototype footprint. To secure an effective data transfer to the mobile phone, we have used an HC-06 as a Bluetooth transceiver. Once collected and sampled (1 Hz rate), the data is then transferred to the mobile phone trough the Bluetooth connection. For user convenience, the mobile application displays current values at 1 Hz frequency along with a time-stamp chart. When the temperature reaches a critical wound level (33-34°C)[4], the device sends a warning notification to the monitoring application that is held by the health-care processionals (i.e. nurses and doctors). In addition, wound maceration[5] and drying[6] notification warnings are detected and sent to the monitoring application. The later values are calculated based on the humidity sensor's raw data. The monitoring application pulls data from the server and evaluates the wound severity by combings all sensors' data. To centralize all collected data, and improve patient monitoring, the raw and analyzed data are stored in a global database that can be accessed from either a web application or the monitoring mobile phone application. Reference: 1. Bamberg, S.J.M., Benbasat A.Y., Scarborough D.M., Krebs D.E. Paradiso J.A. Gait Analysis Using a Shoe-Integrated Wireless Sensor System. IEEE Transactions on Information Technology in Biomedicine, Vol. 12, No. 4, July 2008, pp. 413-423.2. Paradiso, J.A., Morris, S.J., Benbasat, A.Y., Asmussen, E., «Interactive Therapy with Instrumented Footwear,» in the Proc. of the ACM Conference on Human Factors and Computing Systems (CHI 2004), Extended Abstracts, Vienna, Austria, April 27-29, 2004, pp. 1341-1343.3. Benbasat, A.Y., Morris, S.J, and Paradiso, J.A. «A Wireless Modular Sensor Architecture and its Application in On-Shoe Gait Analysis.» In the Proceedings of the 2003 IEEE International Conference on Sensors, October 21-24, Toronto, Ontario, pp. 1086-1091.4. Dini V, Salvo P, Janowska A, Di Francesco F, Barbini A, Romanelli M. Correlation Between Wound Temperature Obtained With an Infrared Camera and Clinical Wound Bed Score in Venous Leg Ulcers. Wounds 2015, Oct 15.5. K.F. Cutting, R.J. White. Maceration of the skin and wound bed. 1: Its nature and causes. J Wound Care, 11 (2002), pp. 275-278.6. G.D. Winter. Formation of the scab and the rate of epithelialization of superficial wounds in the skin of the young domestic pig. Nature, 193 (1962), pp. 293-294