Arduino ESP32 DIY Water Level Sensor and DIY Level Indicator

1/*
2  This code for a WaterLevel sensor and a WaterLevel Indicator has  been developed and produced by Pierre Pennings (December 2018)
3  This application  can be used for various situations where information about the level of water in  a reservoir tank is required
4  e.g. in automatic plant watering systems or in  caravans or campers where there is no direct visibility on the water reserve in  the tank.  
5  The DIY WaterLevelSensor uses 6 pieces of copper electricity wire  connected to a ladder network of 680K Ohm resistors
6  The DIY WaterLevel Indicator  is made with 5 (Neopixel) SMD5050 LEDs with WS2812B controller chips powered with  5 V
7  Every individual LED is adressed from one ARDUINO output pin and the control  adress determined by the measured WaterLevel
8  The WaterLevel is measured periodically  (during only 200 mili seconds, to avoid corrosion due to electrolysis effects)
9  The WaterLevel Indicator is set to the measured water level
10  The measured  WaterLevelValues are not distributed linearly but follow a second grade polynomial
11  Reference values for the measurements are stored in an Array called LEVELarray[]  consisting of 6 positions
12  The actual measured WaterLevelValues are compared  with the values in the Array and consquently the Water level is determined
13  For  this Project, which is part of a bigger plan, an ESP 32 (NodeMCU) is used with 12  Bits ADCs, however an normal ARDUINO UNO (or almost any other model) will do the  job
14  (of course the settings in the code will need to be adjusted, e.g. due  to 10 Bits ADC and different Pin allocations
15  The ESP 32 device works at 3.3  Volt levels, while the WaterLevel Indicator runs on 5 V
16  The 5 Level LEDs have  been built in a separate indicator Display (indicating 1%, 25%, 50%, 75% and 100%  levels)
17  The ESP 32 is fed with 5 V power (from a 5V adaptor or 5v powerbank),  it has an on-board 3.3V voltage regulator
18  The 5 indicator LEDs get the 5V supply  directly from the 5 volt pin of the ESP 32 
19    
20  This code is licensed under  GPL3+ license.
21*/
22
23#include <Adafruit_NeoPixel.h>
24#define NUM_LEDS  5
25
26
27/////////////////////////////////////////////////  initialise the GPIO pins
28const int output27 = 27;                       // pin  27 sends a "0"  or "1" (0 -3.3 V) to the waterlevel measurement circuit
29const  int LevelSensorPin = 34;                 // 12 bits ADC pin 34 senses the voltage  level of the waterlevel sensor (values 0 - 4095)
30const int IndicatorPin = 16;                   // pin 16 sends the control data to the LED WaterLevel Indicator
31
32int  WaterLevelValue = 0;                        // Variable to store the value of the  Waterlevel sensor
33int level = 0;                                  // Variable  of the WaterLevel
34
35//                      0    1    2    3    4    5
36int  LEVELarray [6] = {1125,1245,1450,1720,2080,2630} ;    // Array with the level reference  values to determine the waterlevel
37                                                          //  the "0" level is applicable when there is no water in the reservoir
38                                                          //  the "5" level is applicable when the reservoir is full 
39
40byte color_scheme[]  = {
41  0, 0, 0,                  // no color/ off
42  0, 200, 0,                //  green
43  100, 200, 0,              // yellow
44  250, 150, 0,              //  orange
45  0, 0, 200,                // blue
46  200, 0, 0                 //  red
47};
48
49Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, IndicatorPin,  NEO_RGB + NEO_KHZ800);
50
51///////////////////////////////////////////////////  the setup code that follows, will run once after "Power On" or after a RESET
52void  setup() {
53  Serial.begin(115200);                   
54 
55  pinMode(output27,  OUTPUT);                    // Initializes the power output pin (3.3 V) for the  WaterLevel Sensor circuit
56  digitalWrite(output27, LOW);                  //  Set output27 to LOW; this will send 0 V to the measuring circuit
57
58  pinMode(LevelSensorPin,  INPUT);               // Initializes the water level sensorpin
59  pinMode(IndicatorPin,  OUTPUT);                // Initializes the output pin for the WaterLevel Indicator
60
61  strip.begin();                                 // Initialize all LEDs to "off"
62  
63  for (int t = 0; t < 5 ; t++)
64    {
65    strip.setPixelColor(t, 100,  100, 100);       // After Power On the WaterLevel Indicator LEDs are tested once
66    strip.show();                                // note that the order of colors  of the WS2812 LED strip is R,G,B 
67    delay (200);
68    strip.setPixelColor(t,  0, 0, 0);             // And back to off
69    }
70  for (int k = 4; k > -1 ;  k--)
71    {
72    strip.setPixelColor(k, 100, 100, 100);       // blink for 0,2  seconds going top down and then off
73    strip.show();
74    delay (200);
75    strip.setPixelColor(k, 0, 0, 0);             
76    }
77}
78
79///////////////////////////////////////////////////  the loop code that follows, will run repeatedly until "Power Off" or a RESET
80void  loop(){
81
82  MEASUREWATERLEVEL ();
83  INDICATEWATERLEVEL ();
84  delay(1000);                            // Check for new value every 1 sec;
85                                          //this  value is just for demonstration purposes and will in a practical application be  far less frequent
86}
87//////////////////END of LOOP////////////////////////////////////////////////////////////  
88
89
90/////////////////////////////////////////////////// Hereafter follows  the Function for measuring the WaterLevel (called from within the loop)
91
92void  MEASUREWATERLEVEL ()  {
93  digitalWrite(output27, HIGH);           // make pin  27 HIGH
94  delay(200);                             // allow the circuit to stabilize
95  WaterLevelValue = analogRead(LevelSensorPin);  //Read data from analog pin and  store it to WaterLevelvalue variable
96
97   for (int i = 0; i < 6 ; i++)
98    {
99      if ((WaterLevelValue > (LEVELarray[i] * 0.96)) && (WaterLevelValue  < (LEVELarray[i] * 1.04)))              // allow a margin of 4% on the measured  values to eliminate jitter and noise
100      {
101      level = i;
102      }  
103   digitalWrite(output27, LOW);           // make pin 27 LOW
104   Serial.print("  LEVELarray: "); Serial.print(level); Serial.print(" = "); Serial.print(LEVELarray[level]);Serial.print("   WaterLevelValue: "); Serial.print(WaterLevelValue); Serial.print("  Level:  "); Serial.println(level);
105   // uncomment this code for determining the values  to be put in the LEVELarray [] using the serial plotter and/or serial monitor or  the ARDUINO IDE
106   }
107  }
108
109///////////////////////////////////////////////////  Hereafter follows the Function for Indicating the WaterLevel (called from within  the loop)
110
111void INDICATEWATERLEVEL ()  {
112
113for (int t = 0; t < 6 ; t++)
114    {
115    strip.setPixelColor(t, 0, 0, 0);           // turn off all LEDs on  the WaterLevel Indicator
116    strip.show();                                  
117    }
118    
119int redVal, greenVal, blueVal;                // Set the WaterLevel  Indicator LED with a color defined in the Array color_scheme
120    redVal = color_scheme[level*3];
121    greenVal = color_scheme[level*3 + 1];
122    blueVal = color_scheme[level*3  + 2];
123    
124    strip.setPixelColor(level-1, strip.Color(redVal, greenVal,  blueVal) ); 
125    strip.show();
126    }
127
128