Bob Rudis reviews Kensington's WiFi Finder and finds it wanting: Bob wrote in with some information about his earlier experience with the credit card sized device from Kensington that reports with one, two, or three green LEDs the signal strength of nearby 802.11b or g networks. I asked him if I could share his thoughts, and he agreed.
Just received a Kensington WiFi "Finder" in the post today. I usually am not too disappointed being an "early adopter," but in the case of this product, I wish I had put the money in the iPod piggy bank instead.
The package comes with a tiny, 11-page instruction booklet, a keychain ring and the WiFi "Finder" itself. The WiFinder (easier to type and a better name) is one of the flimsiest gadgets I own now. I would not attach it to my keychain, let alone put it in my pocket. It's the size of a very thick credit card with no quick, consumer-friendly access to the internals (e.g. for changing the battery).
I immediately tried it, since I have an open AP at home. At the time, there were no clients on the network, just the AP happily sending out beacon packets. The WiFinder didn't detect anything. I double-checked the settings of the AP and tried it again. Still no signal registering on the WiFinder.
On a hunch, I started up a couple WLAN clients and had them stream some music and d/l some game demos in order to create a good amount of 802.11b traffic. The WiFinder eventually did pick up the activity, but as soon as the traffic stopped (leaving the AP beacon only), the WiFinder couldn't find anything.
I was going to give their support organization some time to answer a few questions I submitted before contacting you and others, but when I was told that it would be 2 days before I would hear something, I had to start spreading the news.
I checked the Kensington web site support forum for other posts and two others have had problems with WLAN detection. The answers so far (from Kensington) indicate that this device will have trouble picking up anything but strong, open 802.11b AP's (they really backtrack on 802.11g support) with many operational clients. They explicity state that it will not detect WLAN's that have been "designed to be hidden" (whatever that means).
My recommendation is that folks save their money, buy an old iPAQ (or a Zaurus), get a WiFi card for it and run linux + kismet. It may be more expensive, but it will be worth the functionality.