Home Tech: In Your Pocket, a Lost-and-Found

I did not know the cab’s medallion number. I hadn’t collected a receipt. And because I had just gotten off a plane, the iPad in my bag was turned off, so I couldn’t track it using Apple’s location app.

When I asked the concierge at my hotel if there was anything I could do, she shot me a look I’d see on many New Yorkers’ faces over the next few days. It was a look that told me to cut my losses — the grimace a compassionate doctor might make when telling a man he’s got a month to live.

“There’s nothing to be ashamed of — we are all losers,” said Pooya Kazerouni, a Canadian entrepreneur who has thought a great deal about how to avert this sort of absent-minded, kick-yourself-later experience.

Unlike phone-tracking apps, which will help you find your device only once it’s gone missing, Mr. Kazerouni’s system, called Linquet, is meant to prevent you from mislaying things in the first place.

Linquet is a thin, Post-it-size gadget that you can attach to your keys or stuff in your purse or wallet. The device wirelessly connects to your smartphone. Then, when Linquet and your phone move out of range of each other, both devices emit a disquieting ring. If a Linquet had been attached to my bag that terrible night, my phone, which was in my pocket, might have alerted me as I got out of the cab.

The device is also meant to help find stuff at close range. For instance, if you lose your Linquet-tagged keys around the house, you can page them with your phone.

Mr. Kazerouni is just one of several inventors trying to bring incidents of loss down to zero. It’s a big task. Americans lose an average of one cellphone per year, according to a study conducted by Lookout, a mobile security company. A survey by Esure, an insurance firm in Surrey, England, found that Britons spend 15 minutes each day looking for their phones, keys, wallets, sunglasses and other household items.

I suspect I’m a bigger-than-average loser. In addition to big-ticket items like iPads and laptops, I misplace my keys and wallet at least once a day. I frequently forget my credit card at restaurants. I’ve lost so many iPhone headphones that I’ve had to purchase them in bulk. My losses are compounded by the activities of my 2 ½-year-old son, who, like a malicious librarian, routinely misfiles things around the house. Once, after a three-day search, I found the TV remote in the spice cabinet.

After trying Linquet and a half-dozen other gadgets meant to track down lost objects — not just electronics but also keys and wallets — I’m optimistic that one day people will be able to hang on to their possessions. At some point, all our stuff will be networked and mapped, findable with a push of a button. But that time is not yet here. For the most part, the gadgets I tested, including Linquet, were not quite ready for mainstream deployment.

Their main problem is size and battery life. Linquet uses a Bluetooth wireless radio to stay connected to your phone; this requires power, which means you have to recharge the device about once a week. The battery also makes for a bulky design. Linquet is as fat as a stack of six credit cards; I found it uncomfortable to carry around in my pocket.

What’s more, Linquet works only with Android phones, and it requires a monthly fee. You can order a device from the site for a $15 shipping charge, and then you pay $2.99 per month to use it. (Mr. Kazerouni is working on an iPhone-compatible version of Linquet. That version, which I did not test, is significantly smaller and skinnier than today’s model, and it will last a year between charges, he said.)

Other finding-stuff devices I tested suffered similar problems. The Cirago iAlert ($34), Cobra Tag ($43) and Treehouse Labs’ Bikn ($129.99 for a starter kit) all work according to the same principle as Linquet: each has tags that connect wirelessly to your phone, and when the tags are separated from the phone, both devices ring. But I found this did not work very well with the iAlert; it rang inconsistently, sometimes issuing a false alarm when phone and tag were still connected, and sometimes neglecting to make a sound when they were apart.

The Cobra Tag, meanwhile, was even fatter than Linquet, and its battery seemed to require charging every second day.

Then there’s Bikn, the most stylish of the bunch, but also the most cumbersome. In addition to attaching tags to your keys, you must wrap your phone in Bikn’s phone case. Currently, that case works only on iPhone 4 and 4S, not on the current model, the iPhone 5, and not on any other phones. Treehouse Labs is said to be working on a more widely compatible system for Bikn, but until then, its current version is restricted.