Ring Based Wearable Bioelectrical Impedance Analyzer for Body Fat Estimation

A.K. Guptaa, M. Usmanb, W. Xueb
Rowan University, School of Osteopathic Medicine,
United States

Keywords: body composition analyzer, hydration assessment, fitness tracker, health monitor, bioelectrical impedance, wearable sensor, skin impedance


To assess obesity, its causes and consequences, we need to focus more on measuring fat mass. Bioelectrical impedance analysis (BIA) is a method widely used for estimating body composition, in particular, body fat. However, the issue with current commercially available bioelectrical impedance analyzers is that they are large and bulky systems. Even for handheld devices targeting the consumer market, the systems (e.g., OMRON HBF) are still relatively large and cannot be worn for continuous measurements. We present a novel bioelectrical impedance analyzer for body fat estimation. The purpose is to develop a miniaturized and wearable device, which can also provide wireless connectivity to smartphones. The sensing system consists of a ring with four electrodes placed on it. One pair is used to deliver high-frequency alternating current while the other pair senses voltage. This ring provides the user with a convenient measurement experience by placing the index finger and the thumb on the electrode pair positioned on the ring. The other pair of electrodes are installed on the inside of the ring for contact with the finger on which it is worn. The designed sensor calculates the bioelectrical impedance of the human body based on the applied current and measured voltage. This information is then wirelessly transmitted to a smartphone via Bluetooth to estimate the body fat based on the user’s profile (i.e., height, weight, and gender). The designed hardware is placed inside a dust and moisture protected 3D printed enclosure (100% fill) to make sure that the device works properly in harsh environments. The handheld enclosure has a strap attached to it which makes it easier for the user to wear it on the wrist. The only wires leading to the ring are sealed.