Learn about the difference between WiFi vs. Bluetooth, two of the most popular wireless communication methods.
Planning to start your first electronics design project? Chances are you’ll be including some wireless functionality to communicate with the web or other devices. While there are many ways to communicate wirelessly, the two leaders of the wireless world deserve some attention in your list: WiFi and Bluetooth. How exactly do these two technologies work, and how do you know which one to use in your first project? Let’s find out.
Sharing a common foundation
Before we even dive into the differences between WiFi and Bluetooth, it’s important to note that these technologies share a common foundation in the wireless electronics family through their use of radio waves. Radio waves are but one of many electromagnetic waves, including other family members like x-rays, gamma rays, infrared rays, and more. These waves can all defy even the toughest physical barriers, transmitting data, video, audio, and more through the vacuum of space at the speed of light.
On this electromagnetic spectrum, you can measure and classify radio waves that are used in Wifi, Bluetooth, and other applications in two ways:
- Frequency: This is the count of how many electromagnetic waves pass through a given point every second and is measured in Hertz.
- Wavelength: This is the measurable distance between two of the highest points in a radio wave, which can range anywhere from 100 meters to 1 centimeter, depending on the radio wave you’re observing.
Within the radio wave family, there are distinct bands separated by frequency and wavelength, providing specific channels that devices can use. Check out the table below to see how these break down:
|Extremely low frequency||ELF||3–30 Hz||105–104 km|
|Super low frequency||SLEF||30–300 Hz||104–103 km|
|Ultra-low frequency||ULF||300–3000 Hz||103–100 km|
|Very low frequency||VLF||3–30 kHz||100–10 km|
|Low frequency||LF||30–300 kHz||10–1 km|
|Medium frequency||MF||300 kHz – 3 MHz||1 km – 100 m|
|High frequency||HAF||3–30 MHz||100–10 m|
|Very high frequency||VHF||30–300 MHz||10–1 m|
|Ultra high frequency||UHF||300 MHz – 3 GHz||1 m – 10 cm|
|Super high frequency||SHF||3–30 GHz||10–1 cm|
|Extremely high frequency||EHF||30–300 GHz||1 cm – 1 mm|
|Tremendously high frequency||THF||300 GHz – 3 THz||1 mm – 0.1 mm|
WiFi and Bluetooth share their space in the Ultra high frequency (UHF) band between 300 MHz and 3GHz, along with other gadgets like baby monitors, cell phones, and more. In its most recent evolution, you’ll also find WiFi advancing into the Super high frequency (SHF) band between 3GHz and 30GHz.
It’s because of these separate bands that you can listen to things like your morning AM radio talk show while at the same time browsing the web on your smartphone. Connecting through WiFi on your phone uses the UHF band, whereas AM radio uses the lower frequency bands between 535 kilohertz and 1.7 megahertz.
The world wide web of Wifi
WiFi is the most popular method to allow devices to communicate across a local wireless network and connect to the internet. Like other two-way radio devices, WiFi shares some common similarities.
Picture this: Inside your laptop, you have a wireless adapter that can function as both a transmitter and receiver of information in the form of radio waves. Your adapter gets help from an antenna to send and receive information. On the other side of your home, you likely have a wireless router that has another transmitter and receiver that can also share data wirelessly, along with a physical connection to the internet via Ethernet.
Connecting your laptop and router together on the same radio frequency band allows them to communicate with each other and send data back and forth in the form of videos, audio, websites, and more.
2.4GHz and 5GHz
WiFi works on two bands at 2.4GHz (the UHF band) and 5GHz (the SHF band). Simple enough, right? If you need a way to connect a device to the web to communicate with services all around the world, then something like an embedded wifi module on a microcontroller — or even a wireless adapter that can play into a USB or PCI port — will be your best bet. But before you go running off to purchase a wireless adapter, you’ll need to know about the WiFI networking standards.
Fun Fact: WiFi doesn’t actually stand for anything like some people think it does. Its name was created by a brand consulting firm in 1999 when they needed a cooler name for IEEE 802.11b Direct Sequence. WiFi is definitely a bit more catchy!
The evolution of WiFi networking standards
WiFi has steadily evolved over the years to handle our growing needs for faster data transfer rates. It has also had to expand to deal with the increasing number of devices being used on our WiFi networks across the world, including video game consoles, smartphones, digital cameras, tablets, printers, and a whole lot more. Regardless of the device, all WiFi uses the same networking standard.
WiFi and interference
Like any radio wave signal, WiFi is susceptible to interface from other devices using the same frequency band. This can include microwave ovens, cordless telephones, and other Bluetooth devices. Because of this potential for interference, WiFi signals come with different channels, allowing these devices to jump at will. For example, there are 11 channels in the United States.
Keeping it low-key with Bluetooth
Unlike WiFi, Bluetooth is more concerned with small-area networks and connecting individual devices together without requiring an internet connection. The potential for interference with Bluetooth is a lot lower for two reasons:
- Weaker Signals: Bluetooth devices send a much weaker signal than other wireless devices, measuring only one milliwatt. This helps to create a small, isolated bubble of devices that don’t interfere with other wireless devices.
- Hopping Signals: Bluetooth also uses a nifty technology called spread-spectrum frequency hopping that allows it to jump around between 79 unique frequency channels up to 1,600 times per second. So even if two Bluetooth networks hang out in the same channel, it hardly matters since they’ll switch channels in the next second.
Connecting Bluetooth devices
How are Bluetooth devices able to connect, though? You’re probably used to the traditional pair, pin, and connect process. But let’s see what’s going on behind the scenes.
Suppose you just got a new car with built-in Bluetooth and want to stream music from Spotify. Both your car and your phone have a Bluetooth transmitter inside, and each comes with a unique Bluetooth address.
When you connect your vehicle’s Bluetooth to your smartphone, the car’s transmitter will send out a radio signal broadcasting its unique address and look for other transmitters with an address in the same range. Once it discovers the Bluetooth address on your smartphone, you’ll enter a few digits as the standard security process in Bluetooth, and the two devices will connect.
Once connected, this will create what’s called a personal-area network (PAN), also referred to as a piconet. What you’ve created here between your car and smartphone is a little mini-network for your device. The Bluetooth transmitter in your car and smartphone can then jump around from frequency to frequency to avoid interfering with any other piconet cars cruising around the streets.
WiFi and Bluetooth, side-by-side
As you can see, both WiFi and Bluetooth have some very specific functions. You’ll want to use WiFi in your electronics project if you need to connect your gadget to the internet. But if you need to connect devices together without needing an internet connection, then Bluetooth is your tool of choice. Let’s take a final look at some side-by-side comparisons of the technical limitations of both technologies:
Bluetooth has gone through several upgrades, from Bluetooth 2.0 to the latest Bluetooth 5.3. All of the evolutions come with enhanced data rates and low-energy protocols. WiFi has also seen a steady stream of updates, from 802.11b to the most recent WiFi 6, which provides higher data transfer rates and better security protocols.
Bluetooth works on a much lower frequency than WiFi. Many of today’s newest wireless devices take advantage of WiFi’s higher frequency, which isn’t nearly as congested as Bluetooth’s frequency and helps to reduce any potential interference between WiFi and Bluetooth networks.
WiFi can also transfer data at much higher speeds than Bluetooth. However, Bluetooth devices aren’t going to be downloading huge files, and their weaker data transfer speeds are still perfect for audio communications.
Here’s an important one that might affect your project. The range on a Bluetooth network gets cut off much sooner than WiFi. This will be important to keep in mind if you’re designing something like a drone, which will probably need that added range to keep flying.
Because of its greater range and added layers of security protocols, WiFi uses way more power than Bluetooth. If you need a lower-power device, go with Bluetooth, which only uses about three milliamps of current.
With Bluetooth, you can connect up to seven devices together in one personal area network (PAN). WiFi doesn’t have the same limitations, but how many devices a WiFi network can handle will be largely determined by the bandwidth of the router you connect to.
Ride the Wave
There you have it, all the finely combed details about the two most popular wireless technologies: WiFi and Bluetooth. One thing to keep in mind is that neither of these technologies is necessarily better than the other. They both fill very specific niches in the world of wireless electronics and will continue to evolve and advance as time goes on. And it’s not like you have to choose either or — maybe you need both!
Considering adding IoT to your device? Check out this guide.
Did you know that Autodesk Fusion 360 includes a ton of free microcontroller libraries with Bluetooth and WiFi already built-in? Try Fusion 360 for free today to check them out.