Popular Science February 2013

44 The Genius of Erik Demaine Could the secret of breakthrough science be as simple as having fun? By Daniel Engber 30 How to Build a Hero Engineers are making robots that go where humans shouldn't—into disaster. By Erik Sofge 38 Staying Power Severe storms stress the U.S. grid to its breaking point. Here's how to fix it. By Kalee Thompson 50 Derailed Why do American railroads still use 19th-century technology? By Dan Baum 04 From the Editor 05 Peer Review 06 Megapixels: An airbag for cyclists 66 FYI: What's the worst pollutant? 76 The Future then What's New 09 The most accurate digital fitness coach 10 The Goods: A quieter vacuum, and more 12 The first steer-by-wire car 14 Wireless lighting controlled by phone 15 Snow cleanup without the…

IN 2010, I had the pleasure of writing our cover story about CHARLI-L, the first bipedal, self-contained robot built in the United States. It was rickety, cheap, and extraordinary. Engineering such a thing is incredibly hard. Dennis Hong and his team at Virginia Tech were working from the premise that the best way to adapt a robot to a human environment is to mimic the human form. That way it can reach our cabinets and move fluidly through our homes. Now Hong and his team are trying to make something far more complex. This December, as you'll read in our cover story, CHARLI-L's descendant, a bulked-up, ruggedized prototype called THOR, will attempt the eight disaster-response tasks that make up the DARPA Robotics Challenge. No humanoid has managed these tasks before.…

In the United States, only 1 percent of trips are made by bicycle. In the Netherlands, which has only 1/18 of the U.S.'s population, that number is close to 26 percent. With so many bikes on the road, Dutch company TNO is working on a car airbag that deploys outside the vehicle to reduce bicyclist injuries. Upon impact, the airbag, housed under the hood, inflates to cover parts of the windshield and cushion a biker. In tests last November, engineers drove a track-guided car into a dummy on a bike at 25 mph, the average speed of a crash. Accelerometers in the dummy's head and neck and pressure sensors embedded in its limbs indicated brain damage and broken bones. Dummies in collisions with the air-bag had fewer and less severe…

Every January, millions of people resolve to get more exercise. Health-club memberships spike as does interest in fitness trackers, which use accelerometers to record activity. The trouble with those devices, though, is that they rely on binary tracking algorithms—moving or not—so they generally can't tell the difference between a steady jog and vacuuming the living room. The Amiigo is the first tracker that can discriminate between exercises, tally reps, and accurately tabulate calories burned. The device consists of a shoe clip and a Bluetooth-enabled bracelet, each with a three-axis accelerometer, microcontroller, battery, and enough flash memory to store up to five days' worth of data; the band also contains an infrared blood-oxygen and pulse sensor. When the wearer opens the Amiigo smartphone app, it prompts the bracelet to transmit its…

When full-size foosball is hard to find, players can snap an iPad into the Classic Match Foosball table and boot up a game. Each of the eight rods has an optical sensor that relays direction and spin info through the iPad's connector. New Potato Technologies Classic Match Foosball $100 The minibru is a coffeepot and mug in one. A user adds coarse ground coffee and hot water to the 12-ounce French press and then inserts a filter that pushes particles to the bottom. The filter, which doesn't have the usual plunger, doubles as the mug's lining. ThinkGeek minibru $25 The Alize is the most efficient and quietest vacuum of its size. A sensor in the head detects the type of surface, so the 12-pound vacuum can tailor suction strength to…

VASTLY OVERSIMPLIFIED FLY-BY-WIRE EXPLAINER For decades, aircraft engineers have used electronic fly-by-wire systems rather than mechanical connectors and hydraulics to link the pilot's joystick to the wings. This year, Infiniti becomes the first carmaker to deploy the automotive equivalent—steer-by-wire. Infiniti's system, expected to debut on the 2014 G sedan, uses an electronic actuator to measure the movement of the steering wheel. Electronic control modules then relay instructions to another set of actuators, which pivot the steering rack (and, thus, turn the wheels). The computer-controlled system can instantly vary steering ratio and power-steering assist for low-speed maneuvers or high-speed stability. And with no mechanical connection, the system can filter out steering-wheel-tugging “noise” such as rough-road vibration and impacts. Steer-by-wire also improves Infiniti's current lane-departure system. Today, when the windshield-mounted camera senses…