Whale / bicycle sensor

When we ride the bicycle, we always can't pay attention to our back.It's very dangerous.The bicycle sensor can arise the rider and driver to pay
attention and keep safe distance.
It's can be ring to remind the user,and lighting to warnning who too close.
The power use the solar cell,the outer shell can collect the solarenregy.
The shape reference is the whale,and just assign name to.