Battery-free lights

[LockH]

Battery-free lights are powered by the flexing of the tires:
https://www.sciencenewsforstudents.org/article/teens-invention-could-help-light-bikes-night

Starts:

LOS ANGELES, Calif. — A battery-free light invented by a teen from Georgia could replace the reflectors on a bike’s spokes. Its power comes from a flexing of the tires as a bike is ridden. The new device could save plenty of lives, its inventor suggests.

Only one in five bicyclists ride at night, says Thomas Dorminy. But in 2014, a whopping half of cyclist deaths occurred at dusk, dawn or nighttime, notes this 12th-grader at Sola Fide Home School in McDonough, Ga. (That statistic come from the National Highway Traffic Safety Administration.) One way to decrease the number of fatal bike accidents, the 19-year old thought, would be to make bikes more visible to other vehicles.

... includes:

The teen decided to make a device that doesn’t depend on a car’s headlights. It glows on its own. Better yet, it never needs a battery because it’s powered by small bits of a piezoelectric (PEE-eh-zoh-eh-LEK-trik) material. When such materials flex, electrons move inside them to generate an electric current. (The “piezo-” prefix comes from the Greek word piezein. It means “to squeeze” or “to press.”)

8) 8)

... Ends:

The device’s strip of LEDs measures about 5 centimeters (2 inches) long. When sitting still, the strip is only about one-fifth the size of a standard bicycle reflector, Thomas points out. But when the bike’s wheel is rotating, the strip of glowing LEDs creates a bright swath of light that measures almost 150 square centimeters (23 square inches). That’s about six times the area of a reflector. Moreover, this glow would be brighter than a standard reflector. So Thomas says it’s almost certain that his device would be seen more easily than the reflectors used on bikes today.

 

[Chalo]

Bicycles have been using generator lighting for generations. Newer hub dynamos and LED lighting make this a better option than ever before-- no need to mess with the tires just to get feeble safety illumination.

For wheel lighting, something along the lines of the Reelight system, but with the light and coil on the wheel and the magnet mounted on the frame, would be a good approach.