A Multi-Tasking, Multi-Layer and Replaceable Wrist-Worn Environmental Monitoring Sensor Node

The monitoring of ambient working conditions is a crucial part in occupational medicine. In this paper a low power, adjustable and prolonged environmental monitoring device with several sensors is described. The device is designed and demonstrated by using a MLMS (Multi-Layer Multi-Sensor) concept. The entire system is centralized and sensors are distributed in two layers using two types of communication, I2C and ADC, with a micro controller for limited pin management. Physical parameters such as air pressure, humidity and temperature are integrated in one layer. The upper layer is dedicated to the replaceable gas sensors which are sending data through I2C and ADC mode respectively. The device functionality is completed with the notification system layer for user warnings placed at the bottom. These layers are connected appropriately through a SMD and milli-scale board to board connector which is firm and ease of use. The real time data are sent to a smartphone simultaneously to be logged for further analysis. In this paper, a developed version of the previous system is presented in detail. Efficiency and performance as well as power consumption of such unique multi-layer multi-parameter monitoring device in size and weight are evaluated.