Let&rsquo;s face it, sometimes when you are riding a bicycle, gravity sucks.</p><p>Pedaling uphill can be a chore for anyone &mdash; with the possible exception of Lance Armstrong, of course.</p><p>On the flip side, heading downhill is wonderful, just so long as the brakes are working properly.</p><p>What if you could have the best of both worlds? </p><p>That&rsquo;s what the designers of the Copenhagen Wheel hope they&rsquo;ve achieved. The Copenhagen Wheel, which was unveiled in December, allows any bicycle to be turned into a hybrid: part bicycle, part electric bike. The wheel harvests the energy you input while braking and cycling and stores it for when you need a bit of a boost. You know, for those hills.</p><p>&ldquo;It uses a technology similar to the KERS (Kinetic Energy Recovery System), which has revolutionized Formula One racing over the past couple of years,&rdquo; said Carlo Ratti, director of the Senseable City Laboratory at the Massachusetts Institute of Technology. &ldquo;When you brake, your kinetic energy is recuperated by an electric motor and then stored by batteries within the wheel, so you can get it back when you need it.&rdquo;</p><p>Best of all, the Copenhagen Wheel can be retrofitted to the rear wheel of any bicycle.</p><p>&ldquo;The Wheel is a self-contained unit,&rdquo; Ratti said. &ldquo;It can be plugged into any bike without requiring additional electronics or wires. It is fully controlled by your feet: when you pedal forward, the motor supplements your torque; when you pedal backwards to brake, the motor starts regenerating electric energy while reducing your speed.&rdquo;</p><p>The red hub of the Wheel, which contains the motor and batteries, also has sensors that collect information on air and noise pollution, congestion and road conditions. Additionally, there is a meter that records distances and a GPS unit that can remember routes.</p><p>All of the data is sent via a Bluetooth to a smart phone mounted on the handlebars.</p><p>&ldquo;The bike wheel is an extension of your personal mobile device,&rdquo; said Assaf Biderman, associate director of the Senseable City Laboratory. &ldquo;Controlled through your smart phone, the wheel recognizes you as you approach. While you ride, you can switch gears and motor modes using your phone, and receive real-time alerts automatically.</p><p>&ldquo;The Wheel also has a smart security system: if someone rides away with it, the Wheel goes into a mode where the brake regenerates the maximum amount of power and sends you a text message with its location. So in the worst case, the thief will have fully charged your batteries before you get back your bike.&rdquo;</p><p>For more on the project, go to the MIT Senseable City Lab (senseable.mit.edu/copenhagenwheel/).</p><p><hr class="infobox-hr-separator" /> <div class="infobox"> </div>