Sensors and accessories for increased safety. You can equip your electric garage door according to your individual needs. With the help of a light sensor, your electric roller garage door automatically detects obstacles. This is an important feature particularly for people with children. It is often advisable to install a warning light in order to avoid accidents. Every time the door moves, a light signal, or an acoustic signal if desired, is emitted as a warning. If you are worried about a power failure, a hand crank ensures that you'll still be able to operate your garage door.