As technology changes and we are able to connect to more and more devices wirelessly, new issues crop up that we hadn’t had to deal with previously. One of those problems in today’s factories is how to power some of the wireless monitoring devices that we use to gather information.
It’s reasonably common now to see wireless sensors and measurement devices in industrial applications. These small devices can drastically reduce wiring because they can be placed virtually anywhere to measure anything. Powering such small devices is also relatively simple. Or is it? As with consumer devices, battery power seems the most obvious solution. Batteries are cheap and readily available. Some battery types can source low-power devices for years, with lives of over 10 years claimed in some cases. But are these batteries really the answer and do they really last 10 years?
Batteries have interesting issues when it comes to battery life. While a battery may have a long, 10 year lifespan in a laboratory testing setting, the environmental changes that take place on the factory floor can drastically affect the lifespan of a battery, which can cause other problems by requiring that they be checked periodically and replaced costing many man hours and many dollars. There are, however, alternatives to batteries.
There are other options available, all of which reduce strain on the battery, or eliminate it altogether. Low-power wireless technologies, such as Bluetooth Low Energy or ZigBee, reduce the power required to transmit data in the first place. Some technologies also offer the option to mesh network devices in order to use a lower power network. This has issues in itself in that latency times can increase if the mesh network is sufficiently big. This isn’t an issue if data readings are only required every minute or so.
Of course, a significant way to reduce issues related to battery use is to remove the battery altogether. This can be done by energy harvesting, which can be achieved in a number of ways and works very well for low power devices such as sensors. Solar is definitely the most common harvesting solution. Solar panels are more efficient than ever and cost is constantly falling. Solar powered sensors can be implemented almost anywhere and with a long-haul radio solution can be put in the most remote of places.
Both of these are solutions to the battery problem. Both of these solutions have their own problems. Bluetooth Low Energy works well only if data need to be collected every minute or so. Solar requires the initial investment and has the potential to cause surges that can damage the wireless sensors they are supposed to be powering, unless a battery is implemented, which is what the solar power is supposed to be replacing.
It would seem that there are many drawbacks and costs that can be attributed to the introduction of data collection sensors. But, as with any technology, data collection can quickly become a source of savings in both time and money.
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