Two ideas occurred to me recently that I believe would be socially useful. The first is an air-conditioned bicycle helmet. In hot summer weather a foam lined crash helmet is unthinkably hot-it can overheat the brain and possibly damage it.
There should be many ways to manufacture a cold helmet without the foam. One could make a rechargeable battery pack that attaches to the handlebars to power a helmet fan or music player. Instead of styrofoam one could use blue ice packs that are frozen overnight before being worn in the helmet next day. There may need to be a new baffling structure to let it collapse or liquid to pop out with an extreme jolt. These were my first thoughts-good luck in visiting China to have manufactured.
The other is a camera sensor to watch for pedestrians in crosswalks to keep them from being run over by cars. When it sees an actual pedestrian in the crosswalk it could light a strobe visible to all drivers. Many drivers just ignore the walk-don’t walk signs and drive on through sometimes believing it empty. The strobe would let them know when someone actually is walking across the street.