Laser Spoke (LS) is a novel technology to measure power produced by cyclists. Our laser-based technology provides an accurate and affordable method to monitor power during riding. The technology allows our systems to work on any bicycle, enabling their use on racing and recreational bicycles as well as on BMXs and tandems.
Our universal power-monitoring sensor is also distinct in that it is inexpensive and delivers a level of accuracy similar to that obtained with most sofisticated systems available on market.
In operation, when you press on the pedals, all parts of the bikes displace (deform) slightly under the load. The power from your body flows through the propulsion system from pedals to a driving wheel and produces the traction force in the contact between the wheel and the ground. The power can be measured on any moving element of the system, starting from the crank through the chain to the spokes.
Having a certain level of flexibility, the rear wheel operates as a torsion spring twisted proportionally to the applied torque. Deformations of the hub, the rim and the tire are negligible due to their construction and rigidity and the twisting occurs in the spokes region. The power monitoring system invented in our company is based on monitoring of this deflection with precise laser system. The laser and the position sensitive detector are mounted on the hub and an optical right-angle prism is attached to the rim. In operation, a beam is projected from the laser and forms a light spot on the detector surface. The sensor, in turn, produces an electrical signal, which is proportional to the position of the light spot, the beam deflection and as a result to the applied torque. If the wheel is not loaded, the signal is equal to zero or has a minimal value.
Simply put, Laser Spoke is a technology that enables you to use the wheel installed on your bike as defined torsional spring to measure power output.