Hands on with the AR.Drone iPhone-controlled quadrocopter

Thanks to the App Store, you can use your iPhone or iPod touch as a handheld controller for many other devices: iTunes; the Apple TV; TiVo; Logitech, Sonos, and Roku media players; home-automation systems; and many more. But Parrot’s $299 AR.Drone kicks iPhone-app control up a notch, turning your iOS device into the primary—nay, the only—way to control this four-propeller, flying gadget. We’ve been testing the AR.Drone and its free companion app, Free Flight. Here’s a taste of the geeky fun we’ve been having.

The hardware

The AR.Drone with outdoor hull

Parrot calls the AR.Drone a “quadricopter,” the company’s name for a quadrotor or quadrocopter—a rotor-based aircraft that uses four independent rotors. While quadrotors may seem more complicated than traditional helicopters, the design is actually both simpler and more economical: Instead of complex mechanics that control the aircraft by varying the pitch of each rotor blade as it spins, a quadrotor uses fixed-pitch rotors. You control the aircraft by simply varying the relative rate of rotation of each rotor.

The main body of the AR.Drone consists of a styrofoam shell containing the vehicle’s main circuitry and battery compartment. Four metal arms jut out of the shell in an X pattern, the end of each hosting a motor, a flexible-plastic rotor, and a plastic landing foot. On the bottom of the body are two ultrasound altimiter sensors that, along with an internal “inertial unit,” help the AR.Drone maintain its bearings relative to the ground.

Also inside is a CPU running Linux, and a wireless access point that creates a network for controlling the AR.Drone, letting you play games with other AR.Drone owners, and even uploading firmware updates to the AR.Drone’s built-in FTP server (more on those features in a bit). Finally, the AR.Drone features not one, but two onboard video cameras: one in the front, facing forwards, and the other on the bottom, facing straight down. This isn’t your parents’ RC plane.

Before flying the AR.Drone, you must attach one of two included hulls. For indoor use, you slip on the larger hull, which surrounds each rotor with flexible styrofoam. This hull provides a moderate degree of protection for the rotors when you bump—or crash—into things. And you will crash into things when you first start flying the AR.Drone. For outdoor use, once you’ve gotten the hang of flying, you can swap the protective hull for a minimalist version that covers only the main body of the vehicle. The AR.Drone weighs only 11.7 ounces with the indoor hull and just 10.6 ounces with the outdoor version.

Also included with the AR.Drone are a lithium-ion battery, a battery charger and AC adapter, and several bright stickers to help you keep track of which vehicle is which when multiple AR.Drones are flying together.

The software

The hardware is impressive, but what really makes the AR.Drone unique is that instead of controlling the vehicle using a dedicated hardware remote control, you download a free iPhone app, Free Flight, and then use your iPhone, iPad, or iPod touch as the controller.

When you connect the AR.Drone’s battery, the ‘copter automatically creates a standard wireless network with a range of approximately 50 meters. You set your iOS device to join that network—it’s an open network, so no password is required—and then launch the Free Flight app. The wireless network’s name—in the case of our review unit, ardrone_000752—should be obvious enough, but you can change it later using the iPhone app. (Note that once you use a particular iOS device with the AR.Drone, if you later want to use a different iOS device to control the vehicle, you must first manually “unpair” the original iPhone or iPod touch from the AR.Drone using a button on the bottom of the vehicle. This procedure is noted in the setup guide, but it’s easy to overlook.)

Parrot recommends against using the AR.Drone in an area with other Wi-Fi networks. Here in the San Francisco Bay Area, finding a place with no wireless networks is nearly as difficult as hunting unicorns, but thankfully the AR.Drone worked fine even indoors in a room blanketed by multiple networks.

Once you launch First Flight, you’re presented with a horizontal view that looks much like the screen of a dual-thumb iPhone-app game. Tap the small launch button at the bottom of the screen, and after a few seconds of spin-up time, the AR.Drone elevates to approximately two to three feet off of the ground. Once airborne, a four-direction thumb-pad in the lower-right of the screen controls the AR.Drone’s altitude (slide up to elevate, down to descend, continuously or in tap-increments of approximately 10cm) and the rotation of the vehicle (slide left to turn the AR.Drone counter-clockwise, right to turn it clockwise). Press and hold the control button in the lower-left and you can propel the AR.Drone in any direction by simply tilting the iPhone: left to fly to the left, right to fly to the right, forward to move forward, or back to move backwards.

The view from the Free Flight app while controlling the AR.Drone

(In reality, the left and right buttons aren’t limited to the corners of the screen. You can place your thumbs anywhere on their respective halves of the screen—except for where other buttons reside, of course—and the app immediately repositions the onscreen controls under your thumbs. This is a welcome interface decision, because it lets you concentrate on the movements you’re making with your thumbs rather than on whether or not your thumbs are placed precisely over the onscreen buttons.)

As cool as it is, this accelerometer-based control isn’t the Free Flight feature that generates the most oohs and aahs. That would be the fact that the app’s buttons and controls float over a live view from the AR.Drone’s front-facing camera—you see whatever is directly in front of the vehicle. Tap the camera-cycle button on the left side of the screen, and the view switches to that of the AR.Drone’s bottom-mounted camera. These views aren’t high-resolution—especially the one from the bottom-mounted camera, which is considerably inferior to the camera in front—and they don’t refresh quickly enough to let you “fly blind,” but they’re nevertheless fun, especially when the AR.Drone is flying high above you. (I’d love to be able to tap an onscreen button to save the current camera view—minus the onscreen buttons and displays—to your photo library.)

Besides providing an “I’m in the future!” feeling, the iPhone-app approach to remote control lets Parrot do things you can’t easily do with a dedicated hardware controller—at least not without charging as much for the controller as, say, an iPod touch. For example, you can change many aspects of the AR.Drone’s behavior: You can adjust the trim, pitch, roll, and yaw settings; tweak the sensitivity of the app’s accelerometer control; limit the vehicle’s altitude; switch to a one-thumb controller mode; and change the vehicle’s performance based on which hull you’re using and whether you’re flying indoors or outdoors.

The app also lets you install new firmware on the AR.Drone itself: Whenever you launch Free Flight and connect to your AR.Drone, the app checks the AR.Drone’s firmware and installs a newer version, if available. (Where do you get new versions of firmware? Via updated versions of the Free Flight app, downloaded via iTunes, of course.) When I tested this firmware-update feature, the app twice lost its connection with the AR.Drone, but the third try worked like a charm.

The AR.Drone with indoor (a.k.a., protective) hull

Finally, Parrot will be releasing iPhone-app games for the AR.Drone. The first, AR.Flying Ace, is scheduled for later this year and will let you have onscreen dogfights with other AR.Drones connected to the same AR.Drone wireless network. The company is also providing a software development kit (SDK) for third-party developers to create their own games.

The experience

I have to admit that as much as I tried to be objective while testing the AR.Drone, more than once I was having such a good time that I forgot to take notes, mental or otherwise. Although flying the AR.Drone can be frustrating at first—it takes practice to master the controls and how the ‘copter reacts to them—once you get the hang of it, it’s a heck of a lot of fun. As I noted on Twitter last week, the 14-year-old version of me would have done just about anything for a “toy” like this.

(Although you can use the Free Flight app on an iPad, I found that the iPad’s larger size, while providing a larger camera view, felt clumsier. I much preferred using an iPhone or iPod touch.)

The AR.Drone is surprisingly responsive to your gestures, and it can be made even more so by tweaking the Free Flight app’s settings. After a couple flying sessions, I felt comfortable enough with the AR.Drone to start trying more-complex maneuvers: changing altitude while banking, rotating while flying backwards…buzzing the patio table. But even with practice, accidents happen.

When the AR.Drone is in the air but you’re not actively using the controls, the ‘copter enters a hover mode (Parrot calls it “auto-pilot”) where the brains of the AR.Drone automatically compensate—within limits—for gusts of wind or minor bumps. However, once you’re actively controlling the vehicle, this auto-correction feature is limited—bump into the corner of a chair and you’re unlikely to be able to pull out of the resulting nose dive

Perhaps the trickiest part of flying the AR.Drone is when you’re not directly behind it. For example, when the AR.Drone is facing you, tilting your iPhone to the right will cause the vehicle to bank to your left. I also found that whenever I flew over an object—a chair, a table, or similar—higher than the ground, the AR.Drone responded by quickly increasing its altitude, which sometimes led to difficult flying situations.

The aforementioned hover mode comes in handy more than you might think. For example, whenever you release the accelerometer-control button, the AR.Drone automatically levels out and then remains in place until you use the controller again. If the AR.Drone flies out of range of your iPhone, the ‘copter automatically stabilizes and, if higher than 15 to 20 feet off the ground, descends to around 15 feet. And if you receive a phone call while flying the AR.Drone, the ‘copter automatically switches to hover mode and then gently lands.

You can see the AR.Drone in action in this video from our IDG News Service colleagues:

Two of my biggest beefs with the AR.Drone relate to its battery. A full charge of the battery provides only 10 to 15 minutes of flying time, which is often frustratingly short, and it takes about an hour and a half to recharge the battery. If you want longer flying sessions, you’ll need to pungle up for an extra battery or two ($30 each), so you can swap out a dead battery for a fresh one without having to wait for a charge.

To be fair, the AR.Drone’s battery has to be small enough to fit inside the body of the ‘copter, and light enough for the ‘copter to be able to get off the ground, all the while powering quite a bit of gear: four rotors, the CPU, a bunch of sensors, a camera or two, and a wireless access point. But knowing that doesn’t stop you from wishing you could fly for longer periods.

At least keeping track of the current battery level is easy: The Free Flight app displays a battery meter to help you keep track of the remaining charge, and you get a warning on the screen once the battery dips below a particular level. If you don’t land the AR.Drone soon after, the vehicle will automatically land itself.

The other battery frustration is that in order to charge the battery, you must remove the AR.Drone’s hull, disconnect the battery from the vehicle, and then connect the battery to the charger. And depending on the convenience of your electrical outlets, it may end up being easier to remove the battery from the AR.Drone completely. It would be great if you could just plug the charger into a jack on the exterior of the AR.Drone. Similarly, the AR.Drone has no On/Off switch; to turn of the unit, you must disconnect the battery.

We can rebuild him…

As I mentioned, you will crash the AR.Drone, no matter how careful you are. Even with the protective (indoor) hull, bumping into something can cause the AR.Drone’s rotors to simply stop—a safety feature, according to the company—so the vehicle falls, usually onto its side or upside-down. I made it through most of my testing period without inflicting much serious damage beyond scratches and a small dent to the plastic top of the hull, but the last day of testing didn't go so well. While flying the AR.Drone outdoors—using the outdoor hull, as recommended—a gentle gust of wind pushed the 'copter into a tree branch about seven or eight feet off the ground. The rotors stopped and the AR.Drone fell onto a chair, snapping one of the rotor arms in half. Our colleagues at IDG News Service also damaged their AR.Drone—two of the rings on their test unit's indoor hull broke during indoor crashes.

The parts you can purchase for a damaged AR.Drone

At a Glance
  • Parrot AR.Drone

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