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By Ryan Sheldon
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Introduction to IEEE 802.15.4 Communications

Video Introduction to Computer Controlled Relays
IEEE 802.15.4 Troubleshooting Video

This video will help you troubleshoot your IEEE 802.15.4 Relay Controller and get communications up and running.

Undoubtedly, this is one of the coolest technologies I have EVER worked with.  It's wireless, FCC Approved, FAST, Easy to Use, and is surprisingly reliable.  With built in error checking and networking, its very easy for your computer to communicate to large array of devices with minimal effort.


What is IEEE 802.15.4?

Lets back up a bit.  You probably know what a serial port is.  Most computers use to have them built into the motherboard.  If you were to make your serial port wireless you would have IEEE 802.15.4.  Here's how it works.  You need a device called a IEEE 802.15.4 Modem connected to your computer.  Our IEEE 802.15.4 Modems connect to the USB port of your computer, and mounts as a COM port (a standard serial port).  Once plugged in, you are ready to communicate wireless serial data to remote devices from your computer.

Beyond Wireless Serial

IEEE 802.15.4 is actually a lot more than you may think. Based on the IEEE 802.15.4 specification, IEEE 802.15.4 makes provisions for devices to talk to each other or to a computer. What this means for you is that our IEEE 802.15.4 modem may be used to talk to many IEEE 802.15.4 devices (weather they were designed by us or not), and you can choose which device you want to talk to at any time.
By default, your IEEE 802.15.4 modem will be broadcasting data to ALL devices within range (and they will ALL be replying to your data).  If you are new to using IEEE 802.15.4, you may want to start with just having one wireless device talking to your modem. 
Once the remote device is powered up, your computer is ready to communicate to the remote wireless device.  There are NO configurations that you have to go through.  You just start sending ProXR compliant commands to the wireless device, and you will be activating relays (or reading inputs) in no time.  While this wireless serial port is expectedly slower than a real serial port, its speed will NOT disappoint.

Two Levels of Communications

Now that you have your IEEE 802.15.4 modem plugged in and your computer talking to our IEEE 802.15.4 devices.  You may want to talk to Multiple devices in the same location.  There are essentially two levels of communications.  By default, your programs are sending wireless data to our controller.  But you can also take advantage of the extensive command set of the IEEE 802.15.4 modules to choose which device you are talking to.  We will offer some tutorials on how this is done in the future, but just so you get an idea, this process involves sending AT commands (terminal style commands) to the IEEE 802.15.4 modules.  These commands will allow you to choose which remote device you want to talk to.
When talking to multiple devices, you will need to know the Serial Number of the IEEE 802.15.4 module of the remote devices.  Simply power down the remote devices, remove the Blue IEEE 802.15.4 modules from the boards, and note the serial numbers printed on the bottom side.  Reinsert the IEEE 802.15.4 module into our controller while the controller is powered down.  You can now send AT commands to choose which device you want to talk to, specifying the serial number as part of the command.  We will have a tutorial that shows this procedure in full.  But for your convenience, I have posted a photo of a Visual Basic 6 program (below) that shows how I was able to switch between devices.  I am still working on making this easy for my customers, but this has the information you need.

ZB ZigBee Mesh Networking

Soon, we will be supporting IEEE 802.15.4 Series 2 Modules.  We are currently offering Series 1 Modules.  Series 1 and 2 modules will NOT work together.  You will need a IEEE 802.15.4 Series 2 Modem to talk to IEEE 802.15.4 Series 2 devices.  IEEE 802.15.4 Series 2 offers a new feature call mesh networking.  Mesh networking allows your computer to talk to devices that are out of range by talking to devices that are in between the distant device and your computer.  It's like telling your neighbor to tell his neighbor to turn on his lights.  Mesh networking is capable of passing data through other devices to "find" the device it is trying to talk to, all without actually having to be within range of the remote device.  This is a very exiting and promising new technology that takes an already superior device, and makes it even better.  We will be offering more information on Mesh networking as we integrate these features into our product line.
Advantages of IEEE 802.15.4 Communications Disadvantages of IEEE 802.15.4 Communications
FCC Approved Wireless Protocol No Disadvantages, But I do have some comments.
Up to 1 Mile Range  It is all that you can hope for in a wireless technology, but like all wireless technologies, there are distance limitations.  These and all other wireless devices work better when antennas can see each other without obstructions.
Very Fast Communications In comparison to Bluetooth, IEEE 802.15.4 does require an external modem for communications.  This really isn't a fault of IEEE 802.15.4 as much as it is a fault of our computers.  In my opinion, IEEE 802.15.4 wireless communications should be everywhere Bluetooth is.  Not in place of Bluetooth, but in addition to Bluetooth.
Error Checking Built In Bluetooth is faster than IEEE 802.15.4, but for the same money, IEEE 802.15.4 goes up to a Mile where Bluetooth is limited to about 328 feet.
Supports Communications with Multiple Devices  
Very Easy to Implement Wireless Protocol is 100% Transparent to a Direct Wired Serial Connection  
Series 2 Modules Support Mesh Networking  
VERY COST EFFECTIVE, Cheaper than Running Wires!!!!  
If you have any questions about this article, please feel free to contact me at or call our office at (417) 646-5644.  Our business hours are 9:00AM to 4:00PM Central Standard Time.

Quick Sample:

Visual Basic 6 Examples Shows Switching Between IEEE 802.15.4 Devices.  The window on the left is the "main" program.  The window on the right contains various subroutines we are developing.  The program puts the IEEE 802.15.4 modules into Command mode, then tells the IEEE 802.15.4 device which module it wants to talk to, calling the device by its serial number (the long numbers shown on the Left window).  These numbers are different for EVERY IEEE 802.15.4 module, remove the module from the controller (with no power applied) to obtain the serial number of the IEEE 802.15.4 devices.  We will have a formal tutorial later on, but this has enough information to get you started.