Bluetooth is a form of wireless communication that’s become ubiquitous. Since it’s backwards compatible up to version 3, it’s long-lived; as it updates, it gets faster; it’s pretty secure so long as you remember to turn it off once you’ve disconnected your devices from your other devices. What’s the magic trick? It works almost just like WiFi, but at such a small scale that almost any device can manage to broadcast on battery up to 30 feet, sometimes more, depending on the protocol.
So what is it? How does it work?
What Does the Symbol and Name Mean?
The name “Bluetooth” might read like just another brand name or tech term, the way WiFi does to most people now. BlueTooth doesn’t actually stand for anything in particular – it’s named after a king, King Harald ‘Bluetooth’ Gormsson. Because the king united two countries, Norway and Denmark, and Bluetooth technology was going to unite cellular and PC devices, the name was used as a placeholder. However, the other names the tech might have picked up were either already so heavily used it didn’t make sense from a marketing perspective, or couldn’t be fully vetted from a trademark perspective, so the placeholder was what made it to the reveal for marketing. Similarly, the Bluetooth symbol that looks like a letter ‘B’ is actually two runes smushed together, the runes being the initials of King Harald’s name.
Projection
Bluetooth works in much the same way as WiFi – waves are sent through the air from one of the devices, and then caught and decrypted by the other. It sits in the band of 2.4 to 2.48 Ghz, which might sounds familiar if you’ve ever had to look at routers – WiFi usually either functions on the 2.4 GHz to 5 GHz bands. To have short range wireless transmission able to officially use the BlueTooth name, it has to meet a set of SIG (Special Interest Group) standards. If it doesn’t, it can’t be called Bluetooth officially.
Bluetooth sends data packets over the air to a device that then unscrambles them into usable information, very similarly to how WiFi works with some tweaks for user convenience. You can quick pair to a router, for example, but it’s not designed to do that every time a new device needs to connect, and you can connect to internet devices without a password, but it’s not secure the way Bluetooth is, where most devices have to be added, and it typically only lets two devices talk directly to each other at a time.
Potential Problems
Bluetooth is meant to be back-and forwards-compatible since Bluetooth version 3 – whether your devices actually connect and behave as though this is the case? Different matter altogether! Third-party and off-brand products do not always cooperate nicely with name brand ones, and this problem gets worse the further apart in age they are. Sometimes, wireless network transfer that shouldn’t have been using the Bluetooth name sneaks in and uses it anyway, and the manufacturer just doesn’t get caught because the gadget they’re selling is five bucks and the consumers don’t really care enough to pursue it.
One potential problem for Bluetooth devices is lag. Gamers use corded mice because the bluetooth ones are ever-so-slightly slower than the corded ones. This is undetectable in most cases, but it connects to other problems with an independently powered device wirelessly connecting to another. A mouse with a battery that’s dying is going to behave oddly, and it might not be clear why until the battery goes totally dead. A Bluetooth MP3 player whose battery is going out might start jumping or jittering during songs. Speakers and other devices without screens tend to try and alert you that something is about to happen or that they’re losing battery, but if you don’t know it’s dying until it’s hitting 20%, you may have left your house with them at 21% only for them to start complaining the second you go to use them.
Another problem is a security one. Since Bluetooth connection requires both devices to handshake before they can start transferring data, it’s ordinarily pretty safe… until a fraudulent device detects a device looking for a connection, reads the name it’s looking for, and changes its own name to match, convincing it to connect. This is admittedly pretty tough to do, but not impossible! It’s the kind of thing that trips people up at hackathons, a tool high-security offices might have to worry about. A much more pressing issue is that this also drains the battery. Bluetooth is somewhat power-hungry if it’s searching for headphones that it can’t find, so it’s better to turn it off by default anyway!
Can You Connect Multiple Devices?
Small consumer objects can generally only connect to one other device, but this is not actually the limit – certain Bluetooth structures can connect up to seven other devices as long as they’re essentially ‘read only’ in that connection. The head device, the one doing the writing or transmitting, doesn’t actually broadcast – it switches rapidly between devices in a one-to-one to each.
Bluetooth uses profiles to divvie up how different devices will connect. There are profiles for biometric devices, audio connection devices, and video devices. Anything else is slotted into one of these three.
Connection is also not limited to 30 feet, although that’s usually what small consumer devices broadcast at. Devices in different classes (Class 2 being weaker, and Class 1 being stronger) can reach up to 300 feet, and given the power to do so, some can broadcast over half a mile! It’s possible you’ve seen videos of short-range receivers (like the kind car fobs use to connect to the car) being modified to broadcast longer ranges. One risk of this is that the more of these that can communicate, the higher the odds get of finding another device using the same band even though it should be one in XX thousand odds. Similarly, Bluetooth does not have a huge range to play in, and the odds once again get higher the more of them have to communicate – your 30 foot range is actually often playing into your favor. Imagine if every hundredth Bluetooth mouse was using the same band in an office building! They’d start drowning each other out. Bluetooth radio transceivers already have a version of this problem pretty frequently, where drivers in large cities are all trying to use a handful of empty radio bands, but the slots are being filled by other transceivers, so briefly they can hear other people’s music as their radio picks it up off of their Bluetooth broadcaster.
Troubleshooting
Unfortunately, as many Bluetooth devices don’t have screens, it can be tough to tell where a device is getting stuck. Even for the ones that do have screens, thanks to manufacturers using the term when they shouldn’t, it can be tough to tell where something is going wrong and preventing a car’s hands-free audio tools from connecting to an MP3 player when it can handle phones just fine.
The first thing is to make sure both devices are sufficiently charged. Broadcasting even 30 feet out can drain the battery of a device if it’s been on all day without a connection. This is a pretty easy mistake to make with headphones, and sitting and ‘looking’ for another device when none are available to connect is going to eat up battery faster than being connected or off! Mice are similarly tricky – a computer might warn you that the battery is getting low, but the mouse might simply start lagging and jumping instead. Most Bluetooth devices connectable to your phone or computer can at least give a status report on their charge levels so long as they’re able to connect.
Next, check to make sure both devices are in pairing mode. This is important: there are two modes a device can have, one of which is searching for what’s already connected to it before, and one looking for new devices. If it’s in the wrong mode, you won’t be able to find your device in the UI, and you can’t connect.
Similarly, if there’s a large swarm of Bluetooth devices all in one place, the odds are low that two devices might be trying to use the same band, but not impossible. Try stepping away and seeing if the devices can connect away from the ruckus. WiFi can sometimes also cause problems, as it can cross over the upper range of Bluetooth bands, but it’s a pretty uncommon problem to have, so try the other steps first. Microwave ovens (while on) can also interrupt WiFi data transfer, but it’s a much better bet to rule out, say, a router freezing first before worrying about EM radiation leaks!
As a last-ditch effort for basic troubleshooting, restarting both devices can give one or both of them time to do any background updating they might have queued. Not so applicable with non-internet devices, but restarting if either has been on for too long can help there too: devices with RAM can get stuck processing a program action without totally freezing.
Sources: https://www.bluetooth.com/about-us/bluetooth-origin/
(Psst – need help troubleshooting? Wish this was managed for you? Contact us! https://elixistechnology.com/contact/)
