The Micro Lever Switch is very useful for a variety of robot projects. When the lever makes contact with a surface the small microswitch is pushed. These can be used to make bumpers for your robot so that it can detect when it has crashed into walls or other objects. They can also be used as limit switches for a variety of other projects.
These tiny SPDT Single Pole Double Throw snap action type micro switches can be wired as either NO Normally Open or NC Normally closed.