Proximo lets you use your iPhone to find your keys

Macworld - Kensington will formally unveil its new Proximo product this week at the Consumer Electronics Show in Las Vegas, but the company shared a $60 Proximo Starter Kit with MacworldA early. I've spent a few days with the device, which is meant to help you monitor the whereabouts of your iPhone 4S or iPhone 5, along with your keys and potentially other valuables.

I'm in the target audience for Proximo, I think. I lose my keys inside my house with alarming frequency. I rarely abandon my valuables in public places, but even if Proximo could help prevent it from happening just once, that would seemingly be worth it. Proximo is meant to help you stay close to your keys and other valuables, and find them again if you do become separated.

Here's how it works. The Starter Kit includes a key fob and a tag. The fob is about 2 inches long, 1 inch wide, and 0.25 inches thick; it unsurprisingly sports a small metal loop with which you can snugly affix it to your keyring. The fob sports one big button.

While the fob is oval-shaped, the tag is instead a circle, about 1.5 inches in diameter. It too can be attached to a keyring with its slim metal loop. The main difference between the tag and the fob is that the tag lacks a button. Both dongles include tiny integrated speakers.

The two devices work in tandem with a free iOS app also called Proximo. Both the tag and the fob connect to your iPhone via Bluetooth. (They work only with the iPhone 4S and newer because of their use of Bluetooth 4.0 and Bluetooth Smart.)

Once you've paired your devices with the app, you can configure a few moderately confusing settings. You can name each fob/tag, tweak its icon (including using a photo of your choosing), and configure a slew of sounds: the sound the fob/tag makes when it's found by the iPhone, the sound your iPhone should make if it gets too far away from the fob/tag, the sound the fob/tag should make when it gets too far from the iPhone, and "proximity alarm sensitivity."

That last setting is meant to dictate how far apart your iPhone and your fob- or tag-bearing devices can be before the alarm sounds on each. Though there are several options to choose amongst regarding how broad a range the Proximo app should allow before it sounds its alarm, none were broad enough in my testing: With my keys safely on the hook by my garage door, and the family sitting around the kitchen table one room over--a distance of slightly more than 23 feet--my iPhone and the key fob kept sounding the alarm.

Now, I'm rarely in danger of forgetting my keys; I tend to need them when I leave the house or return to my car. But I did consider attaching the tag to my wallet somehow, so that my iPhone could harass me if I tried to leave the house without it. That's a no-go; there's no setting broad enough to make that a feasible option. I've disabled the alarms on both the fob and the tag.

That doesn't render them useless, though. The Proximo app can still page either device: You launch the app, find the device you're after in the Dashboard, and tap Find; seconds later, the fob or tag will start beeping. And when you have the fob in hand but not your iPhone, pushing the button on the fob will make the iPhone sound an alert, provided it's within range.

When a fob/tag isn't in range, the Proximo app's Find buttons change to Last Seen. Tap that button, and you'll see your fob or tag geolocated on a map, plotting its last known location.

Bluetooth Smart is meant to consume little energy. It's hard to test this stuff scientifically, but I felt like my iPhone 5's battery drained roughly 10 percent more quickly than I would otherwise expect it to. That's neither ideal nor terrible. Frankly, the ability to find my keys quickly when they're lost in the house is probably worth the battery impact to me. The battery inside the fobs and tags should last up to six months, depending on how often the devices' speakers are engaged.

Bottom line

The Proximo products and app are clever, and they work. I really wish that the built-in alarm could work with a broader range, so that my iPhone and fob wouldn't sound their alerts until they were a bit further apart; as is, it's too limited for me to use that feature. But Proximo means I can use my iPhone to find my keys, and that's mighty useful when my keys go missing.