Development of Wireless Smart Sleeve Using Pressure Sensitive Resistor

Tactile pressure sensors have gained ever increasing attention in designing flexible electronics, such as wearable devices. Building a pressure sensor characterized by high sensitivity and low implementation costs is a very critical challenge to satisfy. Recently, a new low-cost pressure sensor, namely Velostat, has been proposed. Due to its properties of changing its resistance with either flexing or pressure, it has become popular for making inexpensive sensors for microcontroller experiments. Here, we design a smart sleeve made of Velostat to perform rudimentary controls on a smartphone. We first evaluate the optimum layout of the sensor by conducting three tests on the sensor property, such as area of contact, Velostat area, and layers of Velostat. Based on the test performance, a sensor patch is designed. Then, we develop a novel resistive signal conditioning circuit to convert the pressure on the sensor patch into an electrical signal to be transmitted to smartphones via Bluetooth. Finally, we have also realized an Android application that performs the required operations (e.g., multimedia player controller and an SOS alert system) on the smartphone based on the received sensor data. The functionality of our smart sleeve system is validated in real-time, showing promising results for the design of low-cost smart wearables.