Electronic Design

ZigBee Kits 5

Checking out Digi’s $499 Drop-in-Networking Starter Kit (Fig. 1) took a bit longer than I thought but this was due to the number of options available to a developer within the kit. It is literally designed to be dropped into an existing environment with a minimal amount of work.

The heart of the system is the ConnectPort X8 ZigBee Ethernet router/gateway (Fig. 2). It provides a gateway between wired and wireless networks plus support for VPN and scripting applications. Some ZigBee systems can operate in a standalone fashion but ones used with Digi’s hardware will likely be linked to a conventional network. The ConnectPort X8 can be programmed using Python allowing it to poll ZigBee devices and forward information to nodes on the wired network.

The kit also includes some XBee modules (check out Hopping On ZigBee) and prototype boards (Fig. 3). The latter includes the XBee module that is typically plugged into a proprietary design. The prototype board provides access to the XBee module interfaces. The XBee modules utilize an AT-style command set for programming via the serial port.

The kit comes with an XBee RS-232 adapter, sensor adapter and Watchport/T temperature sensor. The RS-232 adapter can be plugged directly into a serial device. The serial device can be accessed by the adapter via the ZigBee network.

Not included in the kit was the XBee router (Fig. 4). This is a handy device for building larger mesh networks. It plugs into a 110-V ac outlet. The outlet powers the router but it is not a power line networking product. Instead, the router can link ZigBee nodes within range including other XBee routers. It can be used to fill in a hole in a fixed network or it can maintain a mesh where nodes move in and out of the area. Otherwise, the moving nodes would have to be in position to maintain the mesh and that is not always easy when you do not have control over a node’s position.

The wall routers have only an LED and a button. The button is used to link to a network and the LED provides status information. The status of the router can be obtained via the mesh network and the ConnectWare program.

Getting Started
Opening the large box was fun and the first thing in the PC was the CD with the development tools, Python scripts, docs, etc. This includes a 30-day trial version of ConnectWare, Digi’s network management system, which proved invaluable and relatively easy to use (Fig. 5). It runs on a Linux or Windows PC and works in conjunction with the ConnectPort X8 router. The modules can be used without ConnectWare but it is very handy when setting up or managing a network. The CD includes docs for all the components including the XBee modules and plenty of programming samples.

Firing up the various modules and having them connect to the ConnectPort X8 is a relatively trivial exercise. A manual walks you through each step. The modules are designed to start up and run in the network after they are linked to it, typically with a couple button presses. Nodes within the network can be displayed and controlled via ConnectWare.

Loopback plugs are provided to test the RS-232 node. A terminal program interface can be provided via ConnectWare to the node’s serial connection. The X-CTU program allows Windows to map the serial ports from various XBee nodes to COM ports available to Windows applications.

The one area that took a little work was using Python with the ConnectPort X8. The PDF file documentation is on the CD but you need to find it. The Python support is not extensive and debugging can be a chore but the facility allows easy management of scripts including the ability to automatically start scripts.

Overall, I found that the kit will allow ZigBee evaluation and testing with serial devices including nodes based on the XBee modules. More advanced applications can be built using the XBee modules instead of the more complete devices such as the RS-232 nodes.

Digi
www.digi.com

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