Wearable Wireless Body Area Network

The project sponsor asked the team to design a wearable wireless body-area network – a Fitbit is an example of a wireless body-area network – that enables the user to monitor critical body functions by smartphone. The device, worn around the chest, contains three sensors: a combined accelerometer-gyroscope programmed to detect falls, and two sensors to monitor heart rate. Upon detecting a fall, the device’s smartphone app notifies the user’s designated contact. One heart rate sensor uses LEDs and a photodiode to measure changes in light intensity as it bounces off the skin and into the receptor; the other is a three-lead electrocardiogram. The user wears three stickers on the chest, from which wires carrying the heart’s intrinsic electrical signals are fed into the device. The signal is conditioned and amplified, and the reading sent to the user’s smartphone app via a Bluetooth transmitter.