Four Types of Sensors Used in Smart Buildings
Since the advent of automatically regulated heating and air conditioning systems, buildings have possessed some rudimentary form of intelligence. While simple on/off control is useful to keep internal temperatures at the correct level, today’s smart building technology has progressed to the point where inputs far beyond the temperature can be used to control how a building operates. Such inputs can even be used for predictive maintenance to keep building infrastructure functioning properly.
Temperature, Humidity and Environmental Sensors
Mechanical thermostats are useful for rudimentary temperature control, but today we have many other options. As of July 2022, Arrow offers 3,481 temperature and humidity sensors, which include discreet components and devices integrated onto a breadboard with supporting hardware. Such devices can be used in smart thermostats to regulate overall temperature in a more intelligent manner than was previously possible (e.g., automatically adjusting settings when the building is unoccupied).
Environmental sensors, such as air quality sensors and water quality monitors, could be used to help control purification systems. Such sensors might also be used for predictive maintenance to sense when filters need to be changed. Room occupancy numbers could potentially be estimated using an environmental sensor that measures CO2 levels or could even be accomplished via humidity sensing.
Infrared Detection Sensors
Infrared sensors are used to detect human presence, turn on lights or activate an alarm when unauthorized personnel are in an area. One advanced IR sensor on the market today is the Panasonic AMG8833 Grid-EYE Infrared Array. This device combines 64 IR sensors in an 8x8 grid, in an 8.0 x 11.6mm surface-mount package. I was able to try out one of these devices in late 2020, and found that it has just enough resolution to see a finger directly in front of it.
While detecting a finger is interesting, with its 7-meter range, combined with advanced processing, this resolution should be good enough to pick up moving humans, or potentially even gestures. The very low pixel resolution, however, acts to preserve a subject’s anonymity. These sensors could also be used for predictive maintenance, observing how different machinery zones are functioning thermally.
Cameras and Microphones
While IR sensors can give an overall picture of an area, cameras and microphones can get much more specific, either to sense personnel movements or to receive specific commands. Assistant devices like Alexa/Siri/Google Home use audio for robust input capabilities. Certain sounds, like a window breaking, could indicate conditions automatically.
While vision does have tremendous capabilities, and can even be used to identify specific people, in some instances a system needs to know what a person is doing, while keeping the person’s actual identity unknown. One technique is to use a grating instead of a focusing lens to keep the image ambiguous. Purposeful blurring may be further developed in the future to expand where cameras–or perhaps more accurately here, “vision sensors”– can be appropriately applied.
Current Monitoring in Smart Buildings
Current monitoring sensors can be used to show when building equipment is pulling too much power, or to make users aware of how much energy plug-in appliances require. In the case of building equipment, intelligent current monitoring can be useful for predictive maintenance, which could theoretically extend to plug-in appliances as well if the profile is either input or sensed by the system.
Such monitoring could be used to help intelligently manage power usage. During peak energy rates, a system with current sensing could prioritize energy usage to certain appliances over others, or even use stored power, if available.
The Future of Smart Building Sensors
While the current state of smart buildings is impressive, development is always in progress. One might see accelerometers used to monitor building health, and to detect when other systems are vibrating in such a way that they indicate the impending need for maintenance. We may also see capacitive sensing implemented in different input methods, such as walls that respond to touch, or for automatic detection of hands or feet.
However things shake out in the future, it’s certain our buildings will continue to become smarter and more efficient. We’ll certainly see new sensors come onto the market, and the creative application of these technologies with the power of AI and advanced computing resources.
