lock reminder / household

The lock reminder is designed for the aged people who may be forgetful to lock the door or some others. It consists of two chips and two lights. The lights are put in the two sides of the door, bike, or any other that needs to lock. Stick the chips to the lockhole and the lock cylinder, and it will give sign to the light when they were taken apart. Then the light will turn on to remind people of locking.