Motivation
Functionality
Procedure
Step 1: Gathering things
Step 2: The Transmitter Unit
Step 3: The Receiver Unit
Step 4: Code
Durability
Thanks

Published September 20, 2020 © GPL3+

Wireless Water-Tank Level Meter with Alarm

This circuit measure the water level of a tank and wirelessly send it to a receiver where it is displayed using a LCD display and LEDs.

AdvancedShowcase (no instructions)32,072

Wireless Water-Tank Level Meter with Alarm

Things used in this project

Hardware components

Arduino Nano R3

SparkFun Ultrasonic Sensor - HC-SR04

HC-12 Wireless Module

5 mm LED: Red

5 mm LED: Yellow

5 mm LED: Green

Buzzer

Through Hole Resistor, 120 ohm

Resistor 220 ohm

Pushbutton Switch, Pushbutton

Adafruit RGB Backlight LCD - 16x2

Hand tools and fabrication machines

Soldering iron (generic)

Story

Motivation

I always wanted to have a meter which displays the water level of my 1000l water tank in my home. The meters in amazon cost about 70$ and their wireless sensors range is too short. So I build this. This only cost me about 15$ and it was a fun project.

Functionality

This meter sense the water level using an ultrasonic sensor placed under the lid of the tank and sends the data via a wireless transmitter to the receiver unit.

The LCD in the receiver unit displays the water level as a long bar.

The water percentage is calculated and displays in the LCD

A short message like "Low", "Normal", "Full" or "Overflowing", is shown in the display

The receiver contains 3 LEDs. Green, yellow and red which corresponds to the water level

The receiver also has a buzzer which buzzes when the water level is too low or when the tank is full, when refilling.

Receiver contains 2 buttons. The first button turns the back-light of the LCD. Second button mutes the buzzer.

The back-light of the LCD will turn on once the button is pressed and will turn off after 30 seconds.

When the water level is below 15% alarm buzzes, if it was muted it restarts again when the water level is below 10%, and 5%

You can build this by following this procedure.

Procedure:

Step 1: Gathering things

First gather all the parts listed above. Other than these items find some small plastic boxes to house the circuits. if you have a 3D printer you can print a case. I used a HC-12 wireless module for this project which has a 1000m range. If you want you could use a NRF24L01 module. But you might have to change to code.

Step 2: The Transmitter Unit

schematic of the transmitter

Transmitter unit

First build the transmitter unit. Figure out the pins of the parts and connect them to the Arduino. The schematic of the circuit is given below.

Step 3: The Receiver Unit

schematic of the receiver

Receiver unit

Then build the receiver. Carefully follow the pins and connect them to the Arduino. First you should build the circuit in a breadboard and later move to a circuit board. I used a prototyping board for the LEDs and the buttons.

Step 4: Code

Code for both receiver and transmitter are included. To calibrate the sensor edit the MinLevel and MaxLevel in the transmitter code. Use serial communication to get the 2 values.

Go through the code and edit it if needed. You might encounter some software errors while building the project, try to fix them and move on. Remember, "Never Give Up". So, with smart work and dedication, you can do anything!

The receiver display when using

Durability

I'm using this meter in my home for over a year now. The only problem I had was the ultrasonic sensor become rusted because of the high humidity inside the tank. So I had to change it into a waterproof ultrasonic sensor (JSN-SR04T).

Thanks

If any doubts Comment it below

Code

//  Created and Designed by Manusha Ramanayake 
//  Email   : ramanayakemanusha@gmail.com


//Transmitter and Sensor Unit

# include <SoftwareSerial.h>
SoftwareSerial HC12(4, 5);

//Change the values below to calibrate the meter
int MinLevel = 24; //This is the sensor reading when the tank is empty
int MaxLevel = 102; //This is the sensor reading when the tank is full

int power = 6;
long dist_1 = 0;
long dist_2 = 0;
int Time = 0;
int trig = 3; //trigger pin of ultrasonic sensor
int echo = 2; //Echo pin of ultrasonic sensor

void setup() {
//To calibrate the sensor delete the comment symbols in the following code
	//Serial.begin(9600);
 HC12.begin(9600);
 pinMode(trig, OUTPUT);
 digitalWrite(trig, LOW);
 pinMode(echo, INPUT);
 pinMode(power, OUTPUT);
 digitalWrite(power, 1);
}


void loop() {
 
  Time++;
 // Standerd code for getting value from the ultrasonic sensor
  digitalWrite(trig, LOW); 
  delayMicroseconds(5);
  digitalWrite(trig, HIGH); 
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  
  dist_1 = ( pulseIn(echo, HIGH))*0.034/2;   //this gets the value in centimeters
  
  if (dist_1 < MaxLevel+100){  //change if needed
  Send_data(dist_1);}
  
 //debuging code
	//Serial.print(dist_1);
	//Serial.print('\n');
  delay(500);
  
} 
void Send_data(int dist_1){
//maps the sensor values to a number between 0 and 100
 int sent = map (dist_1, MinLevel, MaxLevel, 100, 0);

 //This sends data every 100 ms
 if (Time == 100) {  
  HC12.write(sent);
  Time = 0;
 }
 //This sends data instantly when tank water level is changing
 if (dist_1 != dist_2) {   
    HC12.write(sent);
    dist_2 = dist_1;
 }
 
 //To calibrate the sensor delete the comment symbols in the following code
 
 /*
 Serial.print("    sensor read- ");
 Serial.print(dist_1);
 Serial.print("    sent value - ");
 Serial.print(sent);
 Serial.print('\n');
 */
}

//  Created and Designed by Manusha Ramanayake 
//  Email   : ramanayakemanusha@gmail.com
 
//        Reciver Unit

//Pins
/*  
 *   
 *   --LCD--
 *  RS: pin D12
 *  E: pin D11
 *  D4: pin D2
 *  D5: pin D3
 *  D6: pin D4
 *  D7: pin D5
 *  Vo: A4
 *  D13: gnd
 *  
 *  --HC 12--
 *  Tx: pin 7
 *  Rx: pin 8
 *  
 *  --Button--
 *  B1: pin 9
 *  B2: pin 10
 *  
 *  --LED pins--
 *  G_led: pin A1
 *  R_led: pin A0
 *  Y_led:pin A2
 *
 *  buzzer:A3
*/

// defining libraries
#include <LiquidCrystal.h>   //for LCD 
#include <SoftwareSerial.h>  //for HC-12 wireless module

SoftwareSerial HC12(7, 8);
LiquidCrystal lcd{12, 11, 2, 3, 4, 5};

int backlight_time = 30000;   //The time LCD backlight is turned on in miliseconds
int buzzer_freq = 1000;		//Frequenzy of the buzzer


int refill_time = 17000;    //delay time for the "refilling.." massege
int re_disp_time = 35000;   //"refilling.." massege display time


int refill_Maxtime = 0;
int button1 = 9;
boolean backlight_state = 0;
boolean button2_stat = 0;
boolean button_check = 0;
int button2_state[3] ={ 0, 0, 0};   // to check the button2 is pressed when level is low
int value1 =0;                     
int check1 = 0;
int value2 = 0;
boolean refill_check[3] = {0, 0, 0};  // to check the button2 is pressed when level is high
int data = 50;
int previous_data = 0;
int button2 = 10;
int red_led = A0;
int yellow_led = A2;
int green_led = A1;
int buzzer = A3;
int ground = 13;
int contrast = A4;
int backlight = A5;

// variablals for mult-tasking
long p3Mili = 0;    
long p1Mili = 0;
long p2Mili = 0;
long p4Mili = 0;
long p5Mili = 0;

//custom charachtors for the presantage bar
byte p10[8] = {B00000, B00000, B00000, B00000, B00000, B00000, B00000, B00000};
byte p20[8] = {B10000, B10000, B10000, B10000, B10000, B10000, B10000, B10000};
byte p40[8] = {B11000, B11000, B11000, B11000, B11000, B11000, B11000, B11000};
byte p60[8] = {B11100, B11100, B11100, B11100, B11100, B11100, B11100, B11100};
byte p80[8] = {B11110, B11110, B11110, B11110, B11110, B11110, B11110, B11110};
byte p100[8] = {B11111, B11111, B11111, B11111, B11111, B11111, B11111, B11111};

void setup() {
 //Serial.begin(9600);
  lcd.begin(16,2);
  HC12.begin(9600);

  pinMode(button1, INPUT);
  pinMode(button2, INPUT);
  pinMode(red_led, OUTPUT);
  pinMode(yellow_led, OUTPUT);
  pinMode(green_led, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(contrast, OUTPUT);
  pinMode(ground, OUTPUT);
  pinMode(backlight, OUTPUT);

  lcd.createChar(0,p10);
  lcd.createChar(1,p20);
  lcd.createChar(2,p40);
  lcd.createChar(3,p60);
  lcd.createChar(4,p80);
  lcd.createChar(5,p100);

  
  analogWrite(contrast,10);
  digitalWrite(ground, 0);

  // Boot-up message
  lcd.setCursor(0,0);
  lcd.print("    WELCOME     ");
  lcd.setCursor(0,1);
  lcd.print("       -Manusha-");
  
}

void loop() {
  unsigned long currentMillis = millis();       // Getinng the current timer for multitasking
  boolean button1_state = digitalRead(button1); //button for backlight
  backlight_on(button1_state);
  while(HC12.available ()){
    lcd.clear();

    data = HC12.read();
    if ((data<104) or (data>=0)){
      previous_data = data;
    }
    if ((data>103) or (data<0)){
      data = previous_data;
    }
    display_bar(data);
    miniNote(data);
    display_present(data);
  }
    button2_stat = button2_check(data);     //Button for muting
    level_1(data);                           //led control and alarm
    
   refill(data);                            
    value1 = data;
    if(value2 < value1){
      refill_check[0] = 1;
    }
    if((value2 != value1)&(value2 != (value1 + 1))) {
      refill_Maxtime = 0;
    }
    value2 = value1;

    if( (data > 90) & (data <110)){         //for muting the refilling alarm
        if (button_check == 0){
             button_check = digitalRead(button2);
        }
    }else button_check = 0;

}

int refill(int data){
  unsigned long currentMillis = millis();
  if(refill_check[0] == 1){     //Starting the timer for check a seconadry value.
     if(refill_check[1] == 0){
       check1 = data;
       p4Mili = currentMillis ;
       refill_check[1] = 1;     //starts the second condition
    }
    }

    if(refill_check[1] == 1){
     if(currentMillis - p4Mili > refill_time){      
       if(check1 < data){
        refill_check[2] = 1;    //start to display refilling message
        refill_check[0] = 0;
        refill_check[1] = 0;
        p4Mili = currentMillis ;
        }else {
          refill_check[0] = 0;
          refill_check[1] = 0;
          
        }
        }}

        
        if (refill_check[2] == 1){
          if((currentMillis - p5Mili < re_disp_time)&((data>=0) & (data<100))&(refill_Maxtime<12000)){  
              refill_Maxtime++;
              lcd.setCursor(0,1);
              lcd.print("Refilling..."); 
                  boolean button1_state = 1;      //turn the backlight 
                  backlight_on(button1_state);
                  button1_state = 0; 
          }else{
            refill_Maxtime = 0;
            refill_check[2] = 0;}

       }else p5Mili = currentMillis ;


        
    if( (data > 90) & (data <100)){ 
       if (button_check == 0){ //check for button press
       if (refill_check[2] == 1){ //check whether refilling is started
              if(currentMillis - p3Mili < 300){ //buzzer delay time
                 tone(buzzer, buzzer_freq);}
  
              else if (currentMillis - p3Mili > (map(data, 90, 100, 700, 300))){    //for lowering effect
               p3Mili = currentMillis;
    }
              else  noTone(buzzer);
     
       }
    }else  noTone(buzzer);
    } else  noTone(buzzer); 
    
    return refill_check;
  }

int button2_check(int data){
	//first alarm starts when the level is below 16%
  if ((data < 16) || (data > 200)){   //for low level alarm
    if (button2_stat == 0){
       button2_stat = digitalRead(button2);
    if (button2_state[0] == 0){   //turn the backlight whenever button is pressed.
     button2_state[0] = 1;        //only run once when limit is below 15
     boolean button1_state = 1;
     backlight_on(button1_state);
     button1_state = 0;
    }
       
  }
 //Second alarm starts when the level is below 10%
   else if((button2_state[1] == 0) & (data < 10)){
     button2_state[1] = 1;      //run once when limit is below 10 
     boolean button1_state = 1; //turn the backlight
     backlight_on(button1_state);
     button1_state = 0;
      button2_stat = 0;
    }
//Third alarm starts when the level is below 5%
   else if((button2_state[2] == 0) & (data < 5)){
     button2_state[2] = 1;    //run once when limit is below 5
     boolean button1_state = 1; //turn the backlight
     backlight_on(button1_state);
     button1_state = 0;
      button2_stat = 0;
    } } 
    
  else {
    button2_state[0] = 0;
    button2_state[2] = 0;
    button2_state[1] = 0;
    button2_stat = 0;
    }
 return button2_stat;
  }

//This function displays a messages
void miniNote(int data){
	
   if ((data < 8) || (data > 200)){
      lcd.setCursor(0,1);
      lcd.print("Almost Empty    "); //Keep 16 charachtors between ""
   }
   else if( (data > 7) & (data < 15)){
      lcd.setCursor(0,1);
      lcd.print("Refill          ");    
   }
   else if ((data >14) & (data < 95)){
      lcd.setCursor(0,1);
      lcd.print("Normal          ");
   }
   else if ((data>94) & (data<101)){
      lcd.setCursor(0,1);
      lcd.print("Tank Full       ");
   }
    else if ((data>100) & (data<110)){
      lcd.setCursor(0,1);
      lcd.print("Overfolwing     ");
   }
}

//For the LEDs
int level_1(int data){
  unsigned long currentMillis = millis();
  //turn red led and buzzer when level is below 15
  if ((data < 16) || (data > 200)){
    digitalWrite(red_led, 1);   
    digitalWrite(green_led, 0);
    digitalWrite(yellow_led, 0);
	
	//for the buzzer
    if (button2_stat == 0){
     if(currentMillis - p3Mili < 300){
      tone(buzzer, buzzer_freq);}
  
    else if (currentMillis - p3Mili > 600){
      p3Mili = currentMillis;
    }
     else {
      noTone(buzzer);
     }
      }
    else noTone(buzzer);     
  }
 //turn yellow led when level is between 15 and 30
  else if ((data > 15) & (data < 31)){
    digitalWrite(yellow_led, 1);//turn yellow led
    digitalWrite(green_led, 0);
    digitalWrite(red_led, 0);
    noTone(buzzer);
  }

 //turn green led  when level is between 30 and 100
  else if ((data > 30) & (data < 110)){
    digitalWrite(green_led, 1);//turn green led
    digitalWrite(yellow_led, 0);
    digitalWrite(red_led, 0);
    
  }
  else {
    digitalWrite(red_led, 0);
    digitalWrite(yellow_led, 0);
    digitalWrite(green_led, 0);
    noTone(buzzer);
  }
  if ((data > 16)&(data<90)){
    noTone(buzzer);   
  }
}

//turns the backlight on
int backlight_on(int button1_state){    //for lcd backlight
  unsigned long currentMillis = millis();
  if (button1_state == 1){
    p2Mili = currentMillis;}
  if(currentMillis - p2Mili < backlight_time){
        digitalWrite(backlight, 1);
      }
  else digitalWrite(backlight, 0);
  }
  
// displays the presantage
void display_present(int data) {
  //Serial.print('\n');
  //Serial.print(data);
  //Serial.print('\n');
  if(data<10){
    lcd.setCursor(14, 1);}  //for one digit values
  if((data<100) & (data>9)){
    lcd.setCursor(13, 1);   //for two digit values
  }
  if((data<1000) & (data>99)){
    lcd.setCursor(12, 1); //for three digit values
  }
    lcd.print(data);
    lcd.print("%");
  
}

//displays the water level as a bar
void display_bar(int data){
  if((data >= 0) & (data < 110)){
    int dplay = map(data, 0, 100, 0, 80);   
    if( dplay > 80){
      dplay = 80;
    }
    int qution = dplay / 5;     //for full blocks
    int reminder = dplay % 5;   //for partial blocks
    
    for(int x=0;x<qution;x++){
    lcd.setCursor(x, 0);
    lcd.write(5);
    }
    lcd.setCursor(qution, 0);
    lcd.write(int(reminder));


  }
}

Credits

Manusha_Ramanayake

0 projects • 18 followers

Wireless Water-Tank Level Meter with Alarm