Human being need eyes to see, ears to listen, nose to smell that is we need things to sense the outer world. Same is with Arduino, it needs the sensors to take sense inputs. But what are these Sensors?

They generate analog output values corresponding to real world’s action.

Here is a some brief list of some of the Sensors:

Accelerometer: They Detect tilting. They are also used in Mobile Phone’s (even in yours) for Playing games.

Magnetometers: They detect magnetic field (used for making digital Compass, can also be used as Metal detectors).

Infrared Sensor: They detect distance to the object.

Temperature Sensor: They can tell you about temperature.

As far you have read about Sensors you might be knowing their name. You need to Understand that they are nothing different than other electronics component. We may call them Sensors because they might be changing their Voltage corresponding to the outer world response. Likewise a Temperature sensors changes its resistance with change in Temperature.

It Resistance changes according to this Law:

R = Ro (1 + αT)

So we can get overview of change in temperature by calculating change in resistance.

Sensors sensitivity depends on How much Sensor’s Voltage due to outer world behavior changes. If a sensor changes it value very frequently corresponding to outer changes then its will be having high sensitivity.

Good Sensors:

  •  sensitive to the measured property,
  •  insensitive to any other property (like sound sensor insensitive to infrared light),
  •  doesn’t alter the measured quantity (like thermometer doesn’t lower the temp of thing you measure with it).

We will be using different Sensors to build our Projects So You need to get Familiar with some of these.