Explaining Wireless Sensor Nodes: ZigBee vs. WiFI
This is a great video that is short and to the point when comparing some of the technical aspects of Zigbee and WiFi wireless communication. After you watch the video let’s go over the info and put some Controls Freak-speak to it to better understand the comparisons and some of the technical jargon.
This video brings up three great points about these two types of wireless communication. Let’s take a look at those three items.
Power and Battery Life
In most cases we don’t think twice about the amount of battery power our WiFi enabled phones and laptops consume because our chargers are always just a wall socket away to delivering a fresh stream of recharge juice. However, ya really can’t plug that space temperature sensor into the nearest outlet each day.
The way ZigBee gets such long battery life is in the way the radio of the transmitter works. It has a sleep mode that it goes into when not required to ‘listen’ or ‘talk’. This is the heart of the ZigBee 802.15.4 standard.
Bit Rate or Throughput
In the video, if you were paying attention, you prolly noticed that the amount of data that a ZigBee transmitter can spit out is 250 kb/s. To put that in perspective for those of you not hip to the whole MEGA-bit Flip Chip terminology, the WiFi transmitter spits out a whopping 54,000 kb/s.
The thing ya gotta ask yourself is… Do you need all that speed and bandwidth? No, not at all. We are talking about small devices like temperature, pressure and current sensors that only need to send a few bits of information to allow you to see a simple 3 or 4 digit number on the computer screen.
Range of Communication
Here we see another comparison where ZigBee shines. Zigbee device can reach up to 1000 meters of distance with a good line of sight. Typical WiFi reaches 100 meters or 300 feet. These distance are pretty relative when dealing with the radios inside of a building with walls, ceilings, concrete and metal all around.
Some closing thoughts though… ZigBee mesh networks still rely on wired Ethernet as its backbone or trunk to get all the gathered information from the many sensors and devices back to your front end or computer. The main points of this video is not to show how ZigBee replaces computer network connectivity, but sensor and device connectivity. I think you would be hard pressed to find common, inexpensive WiFi sensors and devices for Building Automation System applications. They just don’t make sense when talking about individual points.
Then again I haven’t actually installed any ZigBee or other wireless devices myself and I wanted to learn some more as I will be utilizing my first wireless devices here in the next couple of months on a truly large project.
Have YOU had any experience with ZigBee or some other brand of wireless devices? I’d like to hear about it in the comments below.