Karen Tay, Singapore's Smart Nation director, was recently in Washington D.C. to run a workshop for the World Bank on how to develop “smart cities." She says: “'Smart cities' is honestly a buzzword... when I get invited to speak, most people expect me to start with cool tech like AR, VR, AI, modeling and simulation, blockchain and the like. The fact is that cities are complex ecosystems with very established ways of operating. If we want to disrupt them with technology in a way that benefits the masses (i.e. not just the upper middle class), we need dedicated work from the ground-up, coupled with political commitment." Karen Tay's five tips for smart city efforts come from conversations and projects with smart city leaders around the world.
Th Barcelona City Council designed Sentilo to monitor noise and air pollution, starting out in a large public square in the city. It has since rolled out its deployment further. It is an open source project whose name is derived from the Esperanto translation of ‘sensor.’ The source code is freely available from its website and is mirrored on GitHub and Sentilo has also been deployed in Reus and Terrassa.
In terms of the system architecture, Libelium Waspmotes transmit the data they collect back to the Sentilo platform via ZigBee and 802.15.4 in 868MHz and 900MHz, as well as using Wi-Fi, BLE and 3G/GPRS. The data is backhauled by the Meshlium hub, which can be linked to Sentilo by Ethernet, Wi-Fi or 3G/GPRS. The Meshlium gateway stores the collated data locally in case it loses its connection with the cloud software. It is driven by Power over Ethernet (PoE), which can be delivered from an AC power line, DC battery or solar panel, or even a car cigarette lighter plug. The gateway uses an Atheros AR5213A IEEE 802.11b/g or 802.11 a/b/g chipset and runs an open source Linux OS called the Manager Meshlium System.
Environmentally rated at IP65 (waterproof and dustproof level), each Meshlium can operate in a temperature range of -20C to +50C and should prove capable of keeping the Waspmote sensor nodes connected to the cloud in most of the weather conditions that Barcelona is likely to see in the future.
The Meshlium can be used in other implementations as a ZigBee to Ethernet router, ZigBee to 3G/GPRS router, Wi-Fi access point, WiFi mesh node (hence the name), Wi-Fi to 3G router, Bluetooth scanner and analyzer, a GPS-3G real-time tracker and a smartphone scanner to detect iOS and Android devices by their MAC addresses. This sort of device, with its many deployment possibilities, is key to building a sustainable and flexible IoT network architecture – especially a network that could be rolled out across an entire city and support multiple simultaneous device deployments.