A T-shirt going on sale in the US this month could help geeks find a Wi-Fi hotspot without needing to turn on a laptop.

The Wi-Fi Detector Shirt, which the online store ThinkGeek will sell for $29.99 (£15), has glowing bars on the front that light up in waves when there's an IEEE 802.11b or 802.11g network in range. As with a network strength indicator on a mobile phone or PC, more bars light up as the signal gets stronger. A cartoon of a classic radio tower and the simple expression '802.11' say it all for people who are looking for this kind of thing. ThinkGeek employee Ty Liotta developed the shirt, which is only available in black.

Wi-Fi Detector t-shirt Until Power Over Ethernet (IEEE 802.3af, but you knew that) goes wireless, a glowing, network-detecting T-shirt still needs batteries. The three AAA cells for this one are concealed in a pocket sewn inside the shirt, according to ThinkGeek. When it's time to wash the shirt, you can take them out and then peel off the glowing decal, which is attached to the shirt with hook-and-loop fasteners. A ribbon cable concealed inside the shirt links the batteries to the decal, and it can go through the wash - as long as you hang dry the shirt.

One thing the shirt can't tell is whether the network in range is open or encrypted. It also can't detect the very latest certified Wi-Fi technology, 802.11n Draft 2.0, which is several times faster than 802.11b and 802.11g networks. There aren't enough of 802.11n networks yet, explained Jennifer Kuropkat, a spokeswoman for ThinkGeek.

Asked whether the Wi-Fi Detector Shirt will solve a critical problem for users, Gartner analyst Ken Dulaney said, "Probably for a very few people in the world, yes."

Related stories:

BT & Fon team on free Wi-Fi

Can BT turn free Wi-Fi hotspots into a reality?