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Sat, 03 Feb 2007
WiFi SRV-1 update

A number of SRV-1 users have been waiting on 802.11 interfaces for the robots, and things have not gone according to plan. We originally expected to have a WiFi radio module for the SRV-1 in November, but that slid to January because of firmware issues, and the latest firmware update has actually pushed things out some additional number of months, so we're now looking at alternatives. At this point, we have 4 viable WiFi module candidates:
  • Lantronix WiPort - we tested these 802.11b/g modules back in September - see http://www.surveyor.com/cgi-bin/robot_journal.cgi/2006/09/02#047. They worked well in a hierarchical network and were easy to configure, but there were some issues:
    • 3.3V supply, requiring additional regulator
    • power consumption was fairly high, though we didn't fully explore the power management options
    • external antenna only
    • limited to 468kbps (though spec'd for 921kbps)
    • fairly expensive if you add up the cost of the module ($120), antenna ($10), switching regulator ($10), special connector ($10) and a PCB to mount everything
    In its favor, we know that the WiPort works, so it remains a viable candidate.

  • DPAC Airborne - similar in specs to the WiPort, though limited to 802.11b speeds. Interface spec is 921kbps, though this has to be tested. Likewise 3.3V, so we need another voltage regulator. Also uses external antenna. List price is $129, so cost probably works out to be comparable to the WiPort.

  • DataHunter Mini-b - much lower cost ($79), built-in antenna option, 5V supply (no extra regulator needed), but UART spec is only 115kbps. We've contacted the manufacturer to see if the interface can be run at higher speeds. If so, this is a very attractive candidate.

  • EZURio WISM - we haven't been able to get much hard data on these radios, but they are really small and the pictures look nice. We should have info in a few days.
The goal now is to get samples of everything, and complete an evaluation within 2-3 weeks so that we can start to provide a WiFi alternative to Zigbee in March. The delays are unfortunate, but we are aware of the need, and should be able to get this back on track.

Posted Sat, 03 Feb 2007 14:25 | HTML Link | see additional stories ...