Wireless Tech and the Energy Harvesting Conundrum
by Mike Fahrion
I’ve been neck deep in wireless technologies for the last few months. And because the world of wireless is changing pretty quickly, I thought I’d share some of the more interesting bits and pieces.
The changes in the wireless world are driven by increased technological capabilities and the need to “connect” more and more of our stuff in the ongoing quest to improve processes, increase uptime and efficiency, and meet ever growing compliance requirements. We’ve progressed beyond asking, “Will wireless work?” The question has now become, “Which wireless tech should I use?” A number of truly rugged and reliable wireless technologies have become available, and there are a lot of applications that can put these technologies to good use.
Here are a few interesting trends:
Cellular data networking continues to grow and evolve. In the US, where our 3G networks were a bit of an embarrassment in comparison to the European networks, the carriers have been very aggressive in building out LTE. This has been much appreciated by iPhone users everywhere. But it has not yet been terribly significant in the world of M2M, where we rarely need huge bandwidth. In fact, the push towards LTE adds hardware cost to M2M routers and modems.
But the cellular industry isn’t blind to the M2M market. Overage charges from Instagramming teens isn’t enough to feed the growth of this industry, so the cellular industry has a roadmap that addresses both people and machines.
On the machine side, watch for the emergence of new categories of LTE that are, ironically, slower. Slower, lower power and lower cost radios will be a good thing for the world of machine-to-machine and industrial Internet of Things applications.
B+B SmartWorx will keep an eye on these trends for you, and we’ll continue to expand our line of LTE routers to stay current with whatever the carriers come up with.
Low-Power Wide Area Networking
Another trend to watch is low power, long range wireless. Some of the buzzwords are “Lora”, “Sigfox” and perhaps “Weightless”. While these technologies differ, their end goal is the same – enabling Low Power Wide Area Networking (LPWAN). LPWAN is about wirelessly transmitting small amounts of data across long ranges, and it will be extremely valuable in applications like M2M networking, smart cities and the Industrial IoT in general.
The very high volume technologies will surely have their roles to play. Bluetooth, for example, started to get interesting when the Low Energy extension was released. A number of different vendors have layered bits of software on top of that, giving Bluetooth devices the ability to listen to and repeat “advertising” data from their neighbors. These Bluetooth devices can then form ad hoc networks that allow for a wider area deployment of radios than you would normally associate with Bluetooth. It’s not terribly sophisticated, and I’m not sure whether it will open up new use cases outside of the consumer world, but the sheer numbers of Bluetooth nodes (phones) and the price point (a bargain) makes Bluetooth worth watching.
The SmartMesh IP wireless sensor mesh technology used in our Wzzard wireless sensor platform continues to impress me. As we deploy Wzzard in more and more sites and environments, we are increasingly impressed by how resilient the technology is. Wzzard doesn’t just work in difficult environments; it does so with zero data loss. And that’s just one benefit. Because the wireless technology is so effective, it makes Wzzard installation a breeze in comparison to its less sophisticated cousins.
The Power Harvesting Conundrum
I was out in California a couple of weeks ago, where I imbibed some of their increasingly rare and precious water and attended the Sensor show. I had a few conversations with energy harvesting technology providers, mostly people who wanted to sell me something to use in our Wzzard platform. Power harvesting and low power wireless sensor tech seem like a natural fit.
But power harvesting continues to be a conundrum for me. I love the concept, but get tripped up by the obvious flaws.
Here’s the question. Today I have a wireless sensing product with multiyear battery life. The batteries in my Wzzard nodes will last as long as 5 or 6 years, depending upon your configuration. If I add an energy harvesting technology – let’s say solar, to keep things simple — I still need a backup battery or a capacitor to keep me going when my source of harvested power falters. In this case it’s the lack of sunlight every night. I’ll also need a second little battery to get me started up when I do the initial installation. (Nobody likes a product that says “You have to put me in the sun for two hours before using me”.) So now I have two batteries, even though my device can harvest energy. And the batteries (or caps) still won’t last forever – they wear out – especially when you install them in the nasty, hot and cold places where our Wzzard goes. So, by adding energy harvesting, I have merely created a more complicated, more expensive product that still needs service. If I’m lucky, I may have doubled the service life, but that’s all. Doesn’t seem worth it.
But energy harvesting is still a very cool idea. In some cases it’s a perfect fit. For example, at the Sensors show I saw some nice little wireless limit switches that were powered by the actuation of the switch. That’s something we’ve seen in the consumer world for a while, but now it’s making its way to industrial. Great use of harvesting technology, and I look forward to seeing more like it. But, for most purposes, we still haven’t figured out how to get along without batteries.
That’s my brain dump for today. Talk back and let me know your thoughts about today’s wireless technologies – and if you have a solution to my harvesting conundrum, I’d love to hear it.
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