Gadgetwise: A Digital Camera From a Kit

A Digital Camera From a Kit

A cross-section of the Bigshot camera.

Learning toys often start as a collection of parts, which after the assembly â€" and presumably the learning â€" collect dust on a shelf (Visible Man model, anyone?)

But the Bigshot camera is an educational kit that, once built, is a usable digital camera with its own battery charging crank, 3-D lens and wide-angle and regular lenses, and online lessons about optics, electronics and imaging.

The camera says it is intended for children 8 and up, although it takes a lot of patience and careful attention to instructions to build the camera. It took me about an hour to complete the project.

The most challenging part was locking down various parts with the small screws that are included. It takes a fair amount of torque to tighten them properly â€" maybe more than an 8-year-old can muster â€" and it requires a deft touch not to strip the plastic sleeves the screws fit in. I had to use my own jeweler’s screwdriver, rather than the screwdriver provided.

As you might expect from a $90 camera you build yourself, the quality of the optics isn’t outstanding. Photos aren’t terribly sharp and the shutter is slow. That doesn’t mean you can’t take good pictures (just ask any photographer involved in the creative Lomography field, which relies on a toy camera).

The Bigshot falls short in two respects. One is the crude software used to import photos. It looks as if it belongs to a decade-old PC. The other is the explanation of the science behind the camera. Much of it is needlessly complex. An 8-year-old may be able to build the camera, but I defy one to understand what this explanation from the Web site means: “The freed electrons are collected in a bucket-like region known as the potential well.”

Gadgetwise: To Build a Better Lego Robot

To Build a Better Lego Robot

The TRACK3R robot from the Lego Mindstorms EV3 kit.

Lego is continuing to expand beyond bricks with its latest Mindstorms kit, which includes construction materials like studs, beams, girders and wheels that are used to build a robot. The only brick you will find here is the robot’s programmable brain.

The new kit, called Mindstorms EV3, is the third generation of Lego’s robotics platform, which was introduced in 1998 and has evolved over the years to include features like sensors, Bluetooth compatibility, USB ports and a remote control. The Mindstorms EV3 kit will be available on Sept. 1 at most major retailers for $350.

Over the years, Mindstorms has attracted a large community of hackers and hobbyists. To encourage those fans to show off their custom designs, Lego will unveil a new Mindstorms Web site on Sept. 1. A mobile app for iOS and Android devices that will include 3-D building instructions will also be released that day.

With more than 550 pieces, the Mindstorms EV3 kit may look a little daunting (it is intended for children and mad scientists aged 10 and above). But the printed step-by-step instructions and color-coded pieces make building the robot, called TRACK3R, much easier.

The instructions follow a modular approach, allowing you to measure your progress along the way. The process alerts you to potential mistakes, which happened to me when I bolted on a few pieces in the wrong direction. Patience and spatial visualization skills are helpful in building the robot, and I found that strong, nimble fingers are required to take it apart.

Once completed, TRACK3R can accomplish simple preprogrammed missions like turning in a circle. Downloadable software offers more advanced missions, help videos and instructions for building four other robots. And the inside of the Mindstorms EV3 packaging includes a mission pad that can be used as an obstacle course for TRACK3R.

Lego says the first robot takes about an hour to complete, but I spent about three hours bent over my coffee table to achieve that. But when I did, I was able to command my creation to rumble forward across the floor toward my cat, terrifying her. Next: world domination.

Gadgetwise: Mix Music Like a Master

Mix Music Like a Master

The EZ Pro DJ mixer from Jakks Pacific.

For anyone who has dreamed of being a D.J., Jakks Pacific makes it easy, even if you don’t have a turntable or records.

The EZ Pro DJ mixer from Jakks Pacific combines two turntables and a sound board in one gadget that connects to an iOS or Android device. Through a free mobile app, the mixer syncs with the music stored on the device. You can assign a song to each turntable and then use the crossfader to blend them together.

Once you get a feel for matching beats (the app can find the beats per minute for each song), you can add studio effects like echo. You can also create loops, add samples and even scratch. The mixer has an input for headphones, allowing you to cue up one song while another one plays. When you’re satisfied with your new sound, you can play it live or record it and save it to a playlist.

For all its features, the mixer is remarkably easy to use. After playing around for about 30 minutes, I was able to create a decent mash-up of Gotye’s “Somebody That I Used to Know” and Sam Taylor-Wood’s cover of “I’m in Love With a German Film Star.” I got a real kick out of blending seemingly disparate songs. The app also includes a few sample tunes than can add a high-energy beat to any song in your library.

The speakers don’t produce very good sound, but the mixer can also be connected to external speakers.

The EZ Pro DJ will be available this fall at retailers like Toys “R” Us and Target for $50. To add your own vocal track, Jakks Pacific will have an EZ Pro DJ microphone accessory for $20.

Gadgetwise: A Smartphone Case Delivers a Jolt

A Smartphone Case Delivers a Jolt

Roy Furchgott for The New York Times

To use the Yellow Jacket stun gun, you have to remove a safety cover from the electrodes, which need to touch skin to be really effective. Next, turn on the switch that arms the stun gun and press the illuminated blue button.

The Yellow Jacket smartphone case is meant to protect more than a phone.

The $140 smartphone cover conceals a stun gun.

Stun guns, of course, have been the subject of some controversy. There have been reports of deaths caused by some of these devices, and film and TV depictions often show people crumpling in a writhing mass when stunned.

After reviewing the specifications of the Yellow Jacket with Steve Tuttle, spokesman for Taser International, the leading manufacturer of stun guns, I was convinced that this case wouldn’t pack a huge punch. According to the spec sheet of Yellow Jacket, the stun gun has an output of 650,000 volts at 0.8 milliamps, which the company said should be painful, but not harmful.

So I tried the Yellow Jacket on myself.

I zapped myself on the inside of my forearm, which Mr. Tuttle had suggested because it has relatively few nerve endings. There was a stinging sensation and I felt an electrical shock travel to my wrist. The shock was really more startling than painful. It was no worse than when I have mistakenly bumped into an electric horse fence, or when as a child someone persuaded me to test a 9-volt battery by touching it to my tongue. Twenty-four hours after I zapped myself, there were small red marks where the electrodes touched me.

Using the stun gun requires some preparation. You have to remove a safety cover from the electrodes, which need to touch skin to be really effective. Next, turn on the switch that arms the stun gun, and then press the illuminated blue button.

Clearly this isn’t the defense of choice in a surprise attack. Perhaps the most effective deterrent for a would-be attacker is the stun gun’s loud buzz and blue arc between the electrodes.

For now, the large and hefty case is available for only the iPhone 4 and 4S. The company says that cases for the iPhone 5 and Samsung Galaxy S4 are in the works.

The Yellow Jacket’s 1800 mAh battery, which is slightly larger than the iPhone’s standard battery, works as backup to increase the phone’s talk time. So if you don’t think a shock will scare off an attacker, you should have plenty of battery reserve to call 911.