Somtimes, we need to measure the level of water in a recipient, or if you want to see the level of water in a tank, it is a requirement to measure the levels of water that it has; so in this section, we will explain how to do this.

The sensor is Normally Open. When the water is over the limit, the contact opens, and it sends a signal to the Arduino board. We use pin number 2, which is a digital input:

We declare the variables and const in the program:

const int buttonPin = 2;     // the number of the input sensor pin 
const int ledPin =  13;      // the number of the LED pin 

We also define the states of the digital signals:

// variables will change: 
intbuttonState = 0;         // variable for reading the pushbutton status 

We configure the signals of the program, inputs, and outputs:

void setup() { 
  // initialize the LED pin as an output: 
pinMode(ledPin, OUTPUT); 
  // initialize the pushbutton pin as an input...