Project26.Reed Switch
============================

Description
------------
The KY-021 Magnetic Reed Switch module is a switch that is normally open and gets 
closed when exposed to a magnetic field, sending a digital signal. Commonly used 
in mechanical systems as proximity sensors.

Specification
--------------
- Operating Voltage	3.3V ~ 5V
- Output Type	Digital
- Board Size	18.5mm x 15mm

Connect
--------
.. image:: /img/connect/26_bb.png

Code
-----
.. code-block:: c

    int Led = 13;      //define LED interface
    int buttonpin = 3; //define magnetic ring sensor interface
    int val;           //define digital variable val
    void setup()
    {
        pinMode(Led, OUTPUT);      //define LED as output interface
        pinMode(buttonpin, INPUT); //define magnetic ring sensor as output interface
    }
    void loop()
    {
        val = digitalRead(buttonpin); // read and assign the value of digital interface 3 to val
        if (val == LOW)            
        {
        digitalWrite(Led, HIGH);
        }
        else
        {
        digitalWrite(Led, LOW);
        }
    }

Phenomenon
-----------

.. image:: /img/phenomenon/26.jpg