Irresistible, Cool, Fun Apps

You know your smartphone doubles as a computer, GPS and video player, but did you know it can also be a metal detector, medical monitor and radio station — if you download the right app.

The sensors, screens and connections on modern phones and tablets are great for staying in touch digitally, but with the right program they can do so much more. Cameras can track your heartbeat, digital compasses might help you find hidden treasure and microphones can measure the ripeness of fresh fruit.
 
Of the thousands of fun apps to supercharge your phone, I’ve picked 10 of the most fascinating and surprising. While all offer some everyday usefulness, they’ll never replace your phone’s raison d’être (um, making phone calls). But if you enjoy exploring the weirder side of digital life — or just want to be the hit of the party — these transformative apps will dial up the possibilities.
 
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10 Unusual yet Practical Apps
 
1. Metal Detector
Platform: Android phones (free)
The compasses built into most smartphones rely on tiny sensors that measure the earth’s magnetic field. Extend the premise just a little and you’re off on a treasure hunt. The same technology can be used to find a pirate’s sunken chest of doubloons or, more prosaically, a set of keys lost in the vicinity of the sofa. This free app displays a simple visual readout of magnetic field strength, and the numbers increase as you get closer to your metal target. It could be particularly useful in do-it-yourself projects, when you want to find (or avoid) metal pipes and wires in walls. 
 
2. Chihuly Glass Blowing
Platform: Apple phones and tablets (free)
Blowing glass is a delightful, creative hobby but it is hard to learn (let alone master), expensive to practice and comes with the risk of inhaling molten sand. Now you can blow glass safely, if virtually, with this artistic app from master glassblower Dale Chihuly of Seattle. Just select a template then blow into your iPhone’s microphone to inflate the glass sculpture. Use your fingers to mold the “hot” on-screen glass into the shape you want, add colors and textures, then upload the design to an online gallery.
 
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3. Leafsnap
Platform: Apple phones and tablets (free)
A walk through the woods is generally restorative, but it can be even more satisfying when you know whether that oak you’re picnicking under is a black jack, chinkapin or sawtooth variety. Let this app from Columbia University be your virtual park ranger. Just grab a fallen leaf, place it on a plain background and snap an image with your phone’s camera. The app then identifies the tree and shows a picture of its flower and fruit. At present it only covers northeastern U.S. species but will soon be rolling out to the entire country. Speaking of trees, the Dogsnap app (also free) works in a similar way to identify dog breeds.
 
4. Mixlr
Platform: Apple phones and tablets (free)
Ever fancied yourself as a DJ or newscaster? This surprisingly simple app lets you start hosting your own live radio show online in minutes. Invite friends over social media or send the link via Web and email; built-in messaging gives two-way communication with your listeners. It’s a great way to start your own talk radio podcast, report breaking news or just share favorite tunes from your phone. A fun feature: You can even save your broadcasts online in perpetuity, also for free.
 
5. 3D Sun
Platform: Apple phones (free)
Obviously your phone can tell you what the weather is like in Phoenix or Jakarta, but it can have far greater reach. With this high-tech app, you can get reports from the surface of the sun. This heliocentric app lets you watch flares, solar “tsunamis” and other eruptions moments after they occur, thanks to directs link from NASA spacecraft. It’s the perfect tool for anyone hoping to catch the northern lights. As the app itself claims, “When the sun explodes, your phone rings.” Fingers crossed you don’t get too many alerts.
 
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6. Instant Heart Rate
Platform: Android phones and some tablets (free)
One of the more useful services today’s smartphones can perform is to track your health. Put your finger over your Android’s camera and this app will pick up the tiny fluctuations in skin color that happen every time your heart beats. (Each beat makes your skin ever so slightly redder.) You won’t want to rely on it for a medical diagnosis, but it can help people check their resting and active heart rates. A similar app for iPhones, Vital Signs Camera ($.99) uses the phone’s front camera to detect breathing rate as well as heartbeats.
 
7. Virtual Zippo Lighter
Platform: Android phones and tablets (free)
At concerts, nothing beats the atmospheric effect of a flickering flame to express your appreciation of a band’s soulful power ballad. But these days, pulling out a real cigarette lighter is likely to get you a security-escorted trip outside. That’s where this virtual lighter comes in handy. It opens with a twist of the wrist, “lights” with your thumb and will sway along with your hand. It will even flutter (although not extinguish) when you try to blow it out. Bonus: You can also sign up for alerts and listings for local bands and DJs.
 
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8. Sonar Ruler
Platform: Apple phones ($.99)
Bats and dolphins augment their vision with echo location: high-pitched squeaks that bounce off potential dangers or prey. This app works in a similar way, emitting little clicks from your phone’s speaker and listening for subtle echoes with the microphone to calculate distance. It’s not as accurate as a laser range finder — in fact, sometimes it’s not even as accurate as gauging the distance by eye — but it’s a great illustration of science in action and could come in handy should the need ever arise to track a shoal of herring in the watery deep.
 
9. Melon Meter
Platform: Apple phones and tablets ($1.99)
Farmers, moms and produce department managers all have tricks for telling whether a watermelon is sweet and ripe or tough and dry. Looking at the color of the stripes is said to work, as is hunting out melons with yellowy bottoms. But why rely on folk wisdom when technology can save the day? Just start this app, place your phone’s microphone on the melon and knock repeatedly. The app listens for the telltale hollow sound of a perfectly ripe melon and displays the results as a “melon meter.” There’s no money-back guarantee if you buy a dud, but the app, which has gotten good reviews, has to work only once to pay for itself. 
 
10. Instructables
Platform: Android and Apple phones and tablets (free)
Despite the preceding, there’s still plenty of cool stuff out there that even the most tricked-out smartphone can’t replace, like hanging moss gardens, electric harmonicas and wooden catapults. But at least your phone can now help you make them for yourself. Instructables is an app and website that tells you how to construct the aforementioned gizmos and 100,000 other do-it-yourself projects, including some of the weirdest inventions, furniture, gadgets, electronics and recipes known to humanity. It’s easy to search and navigate them in the app, which offers step-by-step tutorials complete with photos and helpful text. Just think, you could be just minutes away from your very own disco-ball bike helmet.
 
Mark E. Harris is an award-winning British science, technology and lifestyle journalist based in Seattle. He also writes for The Economist, The Sunday Times, Wired UK and Next Avenue. He tweets from @meharris.