LONDON – STMicroelectronics NV has developed a platform for smart buildings called GreenNet that includes self-powered wireless sensor nodes that can be used to monitor a variety of parameters including temperature and movement. In addition, ST (Geneva, Switzerland) is encouraging a market in software to run on GreenNet networks by opening a dedicated app store.
The GreenNet wireless sensor node contains ST chips for energy management, silicon-based sensors and embedded wireless. It combines a rechargeable battery with a solar cell, a chip sensor and STM32W 32-bit wireless microcontroller in a 3-D system-in-package that operates autonomously powered only by ambient light energy.
Such nodes can be positioned around the home or a building, to monitor temperature, carbon monoxide, or movement sensing and the data transmitted wirelessly to a GreenNet receiving dongle installed in a PC or set-top-box. ST envisions that data could then be communicated wirelessly to mobile device such as a smartphone or tablet computer to provide monitoring and control.
The GreenNet initiative has aim of encouraging greater use of energy monitoring and increased energy saving by turning off un-necessary light and heating. The nodes are addressed using IPv6 and independent developers are being asked to develop downloadable application software for such tasks as home monitoring, security or fire safety.
A sample temperature monitor node can relay one temperature measurement every five minutes based on 150 lux of ambient light available for 6 hours per day. It can also operate autonomously for up to six weeks in the dark. The nodes have an IEEE 802.15.4 radio operating in the license-free 2.4-GHz frequency band.