EARLY ON with Internet of Things projects, choosing IoT hardware meant selecting inexpensive sensors and similar devices that varied little from vendor to vendor. That’s no longer true today, so picking sensors and the supporting edge devices can get complicated. Your checklist for IoT hardware decisions, therefore, must include project requirements, power source, connectivity, and, as always, security.
When it comes to the sensors themselves, there are many manufacturers and a wide range of prices and functionality. For instance, air quality sensors for smart city use cases can start at $50 and go up to $10,000. "The $50 one tells you enough to decide to exercise inside or out, but the $10,000 unit provides reports you can use as evidence in court," says Benson Chan, senior partner at consulting firm Strategy of Things.
Functionality is a key consideration, but so is ease of use for some projects. Gary Russell, owner and president of LiveSmart Technologies, based in the Orange County, Calif., area, says his customers prefer simple, one-touch, one-function command buttons. "Now buttons are complex with eight functions or more, and I have a hard time finding the simple ones," he says.
Another consideration when choosing sensors is the power source. Will AC power be available? If it must be powered by a battery, how often will that battery need to be replaced? Is solar an option? Some small sensors, like those from Everactive (formerly PsiKick), can "harvest" energy from heat or radio waves and don't need a battery; these are well suited for Industrial IoT use cases.
The available network often dictates the endpoint chosen. Russell prefers Z-Wave for home automation, because "it runs at 928 MHz, meaning better penetration than other networks, it uses a strong mesh protocol, and we have very few problems. Almost any Z-Wave device works with any Z-Wave gateway." He also prefers wired to wireless when possible, to get faster speeds and avoid interference issues.
Project size is another factor. On a large scale, such as campuses or cities, LoRaWAN, cellular data, or cell plus LoRaWAN are all reliable network options. Wi-Fi remains popular, and cellular data over 5G will soon become viable too in most cities. Chan says large projects bring extra decisions. "Do you buy one sensor for city use and a different one for the country because of different networks, supporting two device types, or use one network so one device works in both locations?"