How sensors communicate with the internet is a key aspect when conceiving of a connected project. There are a number of ways to connect your sensors to the internet dependent upon the needs and limitations of a particular project.
Key aspects when considering network connectivity:
Here is a matrix of common communication technologies that you can choose from including their tradeoffs.
LoRaWAN or Long Range Wide Area Network, is based on Semtech?s LoRaTM PHY chip, specifically designed and optimised to provide low-power WANs with features to support low-cost mobile secure two-way communication in IoT. LoRaWANs use of sub-GHz ISM bands also means the network can penetrate the core of large structures and subsurface deployments within a range of 2km. LoRaWAN is quickly gaining traction with IoT businesses due to its low cost with a number of initiatives and hardware companies adopting it.
Hubs are supplied by companies such as Multi-Tech and public networks from The Things Network are maturing.Neul
Operating in the sub-GHz band and utilising aspects of the TV White Space spectrum, Neul is comparable to NWave. Based on the WeightlessTM protocol. Can be a good neighbour to other spectrum technology incumbents through use of alternate Whitespace spectrum, reducing channel blocking.
Similar to Sigfox, NWave is a proprietary technology that also forms the basis of the Weightless protocols below. NWave have multiple virtualised hubs allowing for multiple public and private streams. NWave is described as a VPN within public traffic using the Weightless-N standard.
Sigfox uses a technology called Ultra Narrow Band (UNB) and is only designed to handle low data-transfer speeds. An early contender technology, Sigfox already has a large network covering tens of thousands of devices and is currently rolling out across Europe and North America.
Based on a simpler implementation of the NWave technology, -N uses utilises the UNB spectrum however is unidirectional, uplink only. Weightless -P is an improvement upon -N featuring bidirectional capability.
Projects requiring long distance operation can take advantage of GSM/3G/4G+ networks. GSM is ideal for low bandwidth projects that send small messages over the internet, however high power consumption and cost can be problematic for long term remote deployments. Cell networks are a key competitor to low-power WANs.
With near ubiquity on mobile platforms, BLE is a well supported and reliable technology for short-range communications. Bluetooth is designed for transmission of small chunks of data at low energy and is widely used by fire and forget deployments looking to cheaply overlay physical context to digital applications such as Estimote iBeacons.
WiFi is an obvious choice due to its near-universal adoption. As a result, there is expansive existing infrastructure supporting fast data transfer and high quantities of data. However, WiFi requires considerable power.
Realised as a complement to WiFi, in that whilst WiFi has ubiquity, it has clear limitations for use in home automation with regards to security and power usage. Existing IEEE802.15.4 enabled devices can easily upgrade to Thread. Thread provides banking-class security in addition to robust mesh networking designed specifically for home automation.
Like Bluetooth, ZigBee has a number of active deployments albeit in more traditional industrial settings. ZigBee is based on IEEE802.15, an industry standard wireless networking protocol targeting applications requiring infrequent low data-rate exchanges between node and basestation. ZigBee has a number of advantages over BLE, in that is more robust, has a rugged security offering with a high scalability potential due to high node counts.
Operating in the sub-GHz band, Z-Wave is impervious to interference from WiFi and other wireless technologies in the 2.4GHz range such as BLE or ZigBee. It supports mesh networks without the need for a coordinator node and is scalable up to 232 devices on one base. Z-Wave?s protocol is simpler than others, which can enable quicker, simpler development, but is not often used as a comparator to other IoT protocols.