Using Wi-Fi DAQ with a Wireless Ad Hoc Network

Publish Date: Oct 01, 2012 | 0 Ratings | 0.00 out of 5 |  PDF

Overview

A wireless ad hoc network is defined as “a temporary close range connection between wireless devices." An ad hoc Wi-FI network allows you to communicate between two wireless devices without the need for a router or access point. For wireless data acquisition applications, this means you can communicate directly with a WLS-9xxx Wi-Fi DAQ device from your laptop or other wireless host.

The following tutorial provides step-by-step instructions for configuring your computer and wireless DAQ device to use an ad hoc network configuration.

Table of Contents

  1. Step 1 - Configure the Host for a Static IP Address
  2. Step 2 - Configure the Host to Broadcast an SSID
  3. Step 3 - Connect WLS-9xxx to the Host Computer over Ethernet
  4. Step 4 - Configure the WLS-9xxx for Wireless Ad Hoc
  5. Step 5 - Disconnect the Ethernet Cable
  6. Additional Resources

1. Step 1 - Configure the Host for a Static IP Address

The first step is to set your Wireless Network Connection Properties to use a static IP. You can accomplish this by going to:  Control Panel » Network Connections. From here you will change the “Internet Protocol (TCP/IP)” to be similar to Figure 1 below.  You can select any private IP address following the RFC 1918 guidelines.


Internet Protocol TCPIP.png
Figure 1. Wireless Network Connection Properties

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2. Step 2 - Configure the Host to Broadcast an SSID

The second step is to configure your laptop to broadcast an SSID. For Windows XP refer to: Making the Wireless Home Network Connection in Windows XP without a Router and for Windows Vista: Set up a computer-to-computer (ad hoc) network. (Note that if your computer is not set up to use the Windows Wireless Zero Configuration service, these steps may vary.)


Figure 2. Windows VISTA Ad Hoc SSID Configuration


Figure 3. Windows XP Ad Hoc SSID Configuration


If you complete the tutorials in Vista, you will see your connection in a state: “Waiting for users to connect” (Figure 2) and in XP: a red “x” next to the SSID name you just set (Figure 3).

Note: Some computers have a wireless configuration utility created by the manufacturer of the computer or the wireless hardware. These utilities typically run as a background process and may take control of some features of your wireless card, such as power, IEEE 802.11 channel, available networks, etc.

The default behavior of some of such wireless configuration utilities is to automatically connect to any available network in range (ad hoc or otherwise). This may keep you from connecting to your WLS-9163 after the ethernet cable is unplugged, because you configuration utility may already be connected to another wireless network.

Solution: Disable any wireless utility running on your computer and make sure that on your dialog window for: "View Available Networks" in XP and "Connect to a Network" in Vista, your are disconnected from all networks and your new SSID is showing up on the list. The default configuration utility for Windows XP is the Wireless Zero Configuration Utility (WZC).


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3. Step 3 - Connect WLS-9xxx to the Host Computer over Ethernet

The third step is to connect the WLS-9xxx to your computer. You can use a regular Ethernet cable to connect the WLS-9xxx to your computer (no cross over is needed). From here, you can configure the device using Measurement and Automation Explorer (MAX): 

  • Right click on “NI-DAQmx Devices”
  • Select from the list “Find Network NI-DAQmx Devices”
  • Select from “Available Devices”,  the device you want to add
  • Click on “Add Selected Devices"


Figure 4. Find Network NI-DAQmx Devices Dialog

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4. Step 4 - Configure the WLS-9xxx for Wireless Ad Hoc

Now that your wireless DAQ device has been configured in MAX over an Ethernet connection, you must configure the wireless connection.

  • Click the “Wireless Configuration” tab
  • Select your “Country” on the drop down menu (Note: this only appears if the device has been factory-reset)
  • Click on “Radio On” check box (Note: this only appears if the device has been factory-reset)
  • Select “Static” from the “Obtain IP Address Through” pull-down menu
  • Enter an IP address for the Wi-Fi DAQ device that is on the same subnet as your host computer
  • Select the SSID created in Step 1.
  • Select "Ad Hoc" from the “Wireless Mode” drop down menu
  • Select your channel from the “Wireless Channel” drop down menu
  • Click “Save Settings” at the top of the MAX window
  • Click “Yes” for the warning question  of changing the wireless settings




Figure 5. WLS-9xxx Wireless Ad Hoc Configuration in MAX



Figure 6. Successful Ad Hoc Connection in Windows

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5. Step 5 - Disconnect the Ethernet Cable

The last step is to disconnect the Ethernet cable. You can ensure the wireless connection is active by pressing “Refresh" in MAX. The "Link Status (Wireless)" should look like Figure 7 below.

  • Disconnect the WLS-9xxx from the ethernet
  • Press "Refresh" button in MAX



Figure 7. Successful Wireless Ad Hoc Configuration in MAX

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6. Additional Resources

NI ENET/WLS-9xxx User Guide and Specifications

Wi-Fi Data Acquisition Frequently Asked Questions

National Instruments Wireless Data Acquisition

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