recent development related to wheelchairs is the handcycle. They come in a variety of forms, from the road and track racing models to off-road types modelled after mountain bikes. While dedicated handcycle designs are manufactured, clip-on versions are available that can convert a manual wheelchair to a handcycle in seconds. The general concept is a clip-on front-fork with hand-pedals, usually attaching to a mounting on the footplate. A somewhat related concept is the Freewheel, a large dolley wheel attaching to the front of a manual wheelchair, again generally to the footplate mounting, which improves wheelchair performance over rough terrain. Unlike a handcycle, a wheelchair with a Freewheel continues to be propelled via the rear wheels. There are several types of hybrid-powered handcycles where hand-pedals and used along with the electrical motor that helps on hills and large distances. The most recent generation of clip-on handcycles is fully electrical wheelchair power add-ons that use lithium-ion battery, brushless DC electric motor and light-weight aluminium frames with easy to attach clamps to convert almost any manual wheelchair into electrical trike in seconds. That makes long-distance journeys and everyday tasks much easier and keeps wheelchair users hands clean. There have been significant efforts over the past 20 years to develop stationary wheelchair trainer platforms that could enable wheelchair users to exercise as one would on a treadmill or bicycle trainer. Some devices have been created that could be used in conjunction with virtual travel and interactive gaming similar to an omnidirectional treadmill. This convergence of virtual reality and a treadmill have been used for pediatric and adult rehabilitation to regain walking skills. In 2011, British inventor Andrew Slorance developed Carbon Black the first wheelchair to be made almost entirely out of carbon fibre Recently, EPFL's CNBI project has succeeded in making wheelchairs that can be controlled by brain impulses. Interest in electric-powered wheelchairs that are able to climb stairs has increased over the past twenty years. Therefore, many electric wheelchairs with the ability to climb stairs have been developed. Electric-powered wheelchairs with climbing ability need to be stronger and have greater movement in comparison to an electric-powered wheelchair that cannot climb stairs. They must also be stable in order to prevent injury to the wheelchair user. There are currently a number of electric powered wheelchairs that are able to climb stairs available to purchase. Technical developments are continuing in this area. Experiments have also