Arduino® sensors are small devices that can be attached to an Arduino® board to provide the device with information from a physical source. Sensors come in many varieties and are particularly useful for robotics projects, although they can be used for other types of projects as well. Examples of non-robotics projects that use Arduino® sensors include home security systems, remote weather stations, and dishwashers controlled by an Arduino® device.
One of the most basic Arduino® sensors is a light sensor. Unlike a camera, the light sensor cannot produce an image, but instead detects the presence or absence of a certain threshold of light. Using a light sensor, an sensor controlled car could automatically turn headlights on when entering a dark room.
Motion sensors detect changes in light over time to determine if anything within their field of vision is moving. These Arduino® sensors do not provide information about where the moving object is, how large it is, or how fast it is moving. One simple use of motion sensors is turning on lights when someone walks into a room. As with other sensors, motion sensors could be used to trigger any action that the invention is capable of carrying out.
Another type of Arduino® sensor is an audio sensor. Audio sensors detect the presence of sound and can usually provide additional information, such as pitch and amplitude. These sensors are especially useful for devices that have to respond to human actions, such as talking, or actions of other machines, such as beeping.
Tilt and pressure sensors each have particular use in robotics. A tilt sensor allows an Arduino® device to determine when its angle, relative to the ground, has changed, assuming that the tilt sensor is mounted directly to the main body of the device. Alternatively, a tilt sensor could be mounted to a controllable arm and give the Arduino® board constant information about its position. Pressure sensors are critical whenever a robot is dealing with anything that is potentially fragile, such as a glass or egg. Without a pressure sensor, a robot would have no way to determine how hard it was holding something, and could potentially break it.
Robots that move around almost always need some way of determining their distance from other objects. Several sensors exist for this purpose. Infrared distance sensors bounce low power lasers off nearby objects to determine their distance. Sonar sensors use a high tech form of echolocation to determine their position in an environment.