What is Bluetooth?

Your phone has it, your computer has it, your car has it, it seems like just about everything nowadays has it. Bluetooth has become so ubiquitous that it seems a given for any electronic device to have it, but what is Bluetooth? I've been asked this many times, especially in how it's different from WiFi.

Hedy Lamarr. Bet you weren't expecting her in here, were you? This famous actress was actually one of the people that helped invent Bluetooth, though it wasn't called that at the time, and it certainly wasn't invented so you can control your toaster with your computer. She helped invent a way for radio signals to be sent in such a way that they couldn't be blocked or intercepted as part of the wartime effort, but the military simply filed the technology away.

Modern Bluetooth is, in the simplest terms, a way for a wireless signal to be sent in such a way that it "bounces around" various frequencies. Think of it as if you were trying to have a secret conversation over walkie-talkies. You'd hop on one channel, say a couple words, switch to another, some some more words, etc. for your whole conversation. Electronics do this using short-wavelength radio signals, and by using this technology, you can use multiple wireless devices at once with no ill effect.

Even if you have twenty Bluetooth devices turned on and working at once (you have a Bluetooth headset on your phone, wireless mouse and keyboard on your computer, wireless printer, etc.) you'll get no interference between them because they're jumping around on their signals enough that it's highly unlikely that any two objects will be using the same wavelength at the same time, and even if they do, they use it for such a short amount of time you won't notice it.

Practical Tip of the Day:

Most phones and computers that have Bluetooth capabilities have it turned on by default. Having this running if you're not using it can not only drain your battery, but can also be a security hazard. If you see the Bluetooth symbol (see right), go into your settings and turn it off until you do need it.

Why Does My Phone Make My Radio Buzz?

When I first started dating my now husband, I went down to his house to watch a movie, set my phone down by his computer, and all of a sudden his speakers starting making an odd sound. (Sample audio on this website) While it's most common to hear that sound caused by a cell phone and affecting speakers, I also have a friend who was stumped as to why her bedside FM radio was static-y when she sat in bed with her laptop in her lap... unless she held her left hand up.

These are both examples of interference- though two different kinds. I'll be discussing the cell phone/speaker interference first. So what causes it? If you've ever heard it happen, you may have noticed that it happens right before the phone receives a call, text, or an email. This is because what you're hearing is the cell phone "talking" to the cell phone tower and vice versa. Little radio transmissions flying through the air to get to the phone are also being picked up by the speakers.

Not all speakers do this though. More and more speakers nowadays are coming with shielding that blocks out those kinds of signals, but if you have older speakers, or, in our case, speakers whose cables have been chewed on by a kitten, you may still hear it.

And the left-handed radio/laptop interference? From what I could get of the situation, it sounded like her laptop was picking up/sending out signals (my guess is that she had a device plugged into her computer that gets the Internet the same way a cell phone does), and when she had both hands on the laptop, her body was being a sort of antenna. While this is a bit freaky sounding, keep in mind that our bodies are mostly salt water, which is a great conductor. As soon as she picked up her left hand she wasn't as good of an antenna, and therefor the radio couldn't "hear" the interference.

Practical Tip of the Day:
While there's no good, easy way to shield a speaker you already have, there is a very easy, simple trick to stopping interference between a cell phone and speaker- move the phone! Bet you were expecting a complicated technical answer weren't you? Nope, sometimes the best way is the simplest way. Moving the phone away just a foot or two often fixes the issue.