Invented by Ericsson in 1994, Bluetooth was intended to enable wireless headsets. Bluetooth has since expanded into a broad variety of applications including Bluetooth headsets, speakers, printers, video game controllers, and much more.
Bluetooth is also important for the rapidly growing Internet of Things, including smart homes and industrial applications. It is a low power, low range, high bandwidth connectivity option. When Bluetooth devices connect to each other (for example, your phone and your wireless speaker), it follows the parent-child model, meaning that one device is the parent and other devices are the children. The parent transmits information to the child and the child listens for information from the parent.
A Bluetooth parent can have up to 7 children, which is why your computer can be connected via Bluetooth to multiple devices at the same time. When devices are connected together via Bluetooth, it’s called a “piconet”.
Not only can a device be a parent in one piconet and a child in a different piconet at the same time, but the parent-child relationship can also switch. When you put your Bluetooth device in pairing mode to connect it, it’s temporarily becoming the parent so that it can establish a connection and proceeds to connect as the child.
In contrast to WiFi, which we explored in the previous chapter, Bluetooth was meant for portable equipment and related applications therefore excels when you need to connect two devices with minimal configuration. Also, because Bluetooth uses weak signals, there’s limited interference and devices can communicate in “noisy” environments.
In the Industrial Internet of Things, machines often need to send short bursts of data in extremely noisy environments. With potentially hundreds of sensors and devices sending data, WiFi poses too much hassle to set up.
A drawback of Bluetooth is lower bandwidth, but for many industrial applications this higher bandwidth simply isn’t needed.
Bluetooth is also useful in a smart home setting. Again, many devices in the smart home don’t need high bandwidth connections and it’s much easier to set up Bluetooth.
Furthermore, newer versions of Bluetooth can create a self-healing mesh network which means that individual devices can still communicate even if one device runs out of power or is disconnected. If your door locks, HVAC system, washer, dryer, fridge, and lights are all connected, you certainly wouldn’t want them all to fail just because one goes down.
The Bluetooth Special Interest Group officially adopted Bluetooth 5 as the latest version of Bluetooth back in December 2016.
“With Bluetooth 5, Bluetooth continues to revolutionize how people experience the IoT. Bluetooth continues to embrace technological advancements and push the unlimited potential of the IoT.”
As is clear from Bluetooth SIG’s announcement, Bluetooth 5 is specifically aimed at the Internet of Things. It boasts quadruple the range, double the speed, and boosts broadcast messaging capacity by 800%. It also introduces the mesh networking capability mentioned above.
Bluetooth 5 is backwards-compatible with previous versions of Bluetooth, but new hardware is required to take advantage of the new benefits listed above. So it might be awhile until we see all the benefits that Bluetooth 5 has to offer, but it’s an exciting development as the Internet of Things continue to gain traction.
In addition to the capabilities explored above, Bluetooth can also provide indoor asset tracking by using multiple Bluetooth beacons and using their relative signal strengths to triangulate position. GPS is great for outdoor applications but has inherent accuracy limitations and fails indoors when sensors/devices can’t receive the signal from the GPS satellites.
Together with the advantages in noisy environments and the ease of setup, Bluetooth is therefore a strong option for many indoor Internet of Things applications.