In a previous blog article looking at radio technologies, we suggested that the winners in the race were likely to be based around Bluetooth, Zigbee and the emergent 5G technologies. Unsurprisingly, it turns out that life is more complicated than this, and there is a lot more going on within selected niches as well as elsewhere outside of the UK.

Whilst collaborating with a smart home energy saving business, OpenTRV, one of the things that becomes obvious is that it is super important in the home environment for devices requiring remote control to be able to communicate with a central/controller hub. There are number of ways of tackling this:

• Plug all the devices in, use Wi-Fi and hope that all devices can reach the home Wi-Fi hub
• Plug all the devices in, use Wi-Fi with range extender units e.g. using powerline technology
• Go battery powered and use a low power “mesh network” of devices based on Bluetooth or Zigbee technology and hope that this will help solve all nodes reaching the hub
• Go battery powered and use a low power wireless technology that has a better range in the first place e.g. sub-GHz radio based at 433MHz or 868MHz

There are different likelihoods of success and a number of pros and cons with each of these approaches: installation/wiring of sensors to an electricity supply, cost of extra connectivity units, battery replacement costs, data throughput, design margin/certainty of connections etc. In the home environment, product businesses have often tended to pick the last approach for the out of box certainty of connection and are big users of the sub-GHz radio technologies e.g. Lightwave & Mi|Home products.

Now “sub-GHz” wireless technologies may not be that familiar to people who know Bluetooth and Wi-Fi from their mobile phones, but they turn out to be surprisingly well supported by silicon vendors with a wide set of chipset offerings e.g. Texas Instruments CC1310, ST Microelectronics S2-LP, Nordic nRF-905, Silicon Labs EZR32WG, NXP MKW01Z128, Renesas RL78/G1H etc.

Silicon Labs sub-GHz evaluation board

Whilst the sub-GHz radio solutions for home sensors enjoy longer range e.g. 100m with low power, they do have the disadvantage of being unable to natively communicate with mobile phones or the internet. To do this, they need a compatible receiver box which has to be connected to the home router or Wi-Fi hub. This in itself is not a major issue as all home solutions currently rely on a physical “box” for providing the control element of the solution.

But could this box disappear into the cloud in the future? Certainly, but consumers may become worried if increasing numbers of their critical home systems lack the backup of local controls and they become totally dependent on both their broadband provider AND their home automation service’s cloud operation.