Reserve Fuel Tank Monitor and Transfer

1// set variables needed to translate button states and delay timer
2#include  <U8g2lib.h> //Include library for 128x64 OLED 2.42 display
3#include <Wire.h>
4
5U8G2_SSD1309_128X64_NONAME0_F_HW_I2C  u8g2(U8G2_R0, /* reset=*/ 10);
6int fuelPin = A0;
7int fuelValue = 0;
8int  level = 0; //29 represents the tank displaying as FULL
9int pumpState = 0;
10int  gallons = 0;
11float volume = 0;
12byte onPin = 9;
13byte modePin = 11; //selects  transfer screen with on button
14const byte enterPin = 12;  //Starts pump with  momentary button
15byte enterState = 0; //state of button for committing pump start
16byte  sensorPin = 2; //flow meter signal input and initiates interrupt
17byte upButton  = 4;//Up botton to incement fuel volume request
18byte downButton = 3;//down button  to decrement fuel volume request
19int counter = 0;
20const byte pumpPin = 13;  //output pin to BOB for relay
21int dt = 100;
22byte sensorInterrupt = 0;  //  0 = digital pin 2 flow meter input
23float pulseFactor = 2.5; //milliters per pulse
24float  gallonFactor = 0.26417; //amount of gallons/Liter
25
26volatile int pulseCount;  //variable must be volitile when used in interrupt routine
27
28float flowRate;
29unsigned  long int flowMilliLitres;
30unsigned long totalMilliLitres;
31
32unsigned long  previousTime;
33unsigned long elapsedTime;
34
35void setup() {
36
37Serial.begin(9600);
38u8g2.begin();
39u8g2.clearBuffer();
40
41pinMode  (pumpPin, OUTPUT);
42pinMode (onPin, OUTPUT);
43pinMode (modePin, INPUT_PULLUP);  //just need to ground pin to activate (LOW is active)
44pinMode (enterPin, INPUT_PULLUP);  //just need to ground pin to activate (LOW is active)
45pinMode (upButton, INPUT_PULLUP);  //just need to ground pin to activate (LOW is active)
46pinMode (downButton, INPUT_PULLUP);  //just need to ground pin to activate (LOW is active)
47digitalWrite(pumpPin, LOW);
48  
49  pinMode(sensorPin, INPUT);
50  digitalWrite(sensorPin, HIGH);
51
52  pulseCount        = 0;
53  flowRate          = 0.0;
54  flowMilliLitres   = 0;
55  totalMilliLitres  = 0;
56  previousTime      = 0;
57
58  // The Hall-effect sensor is connected  to pin 2 which uses interrupt 0.
59  // Configured to trigger on a FALLING state  change (transition from HIGH
60  // state to LOW state)
61 attachInterrupt(sensorInterrupt,  pulseCounter, FALLING);
62}
63
64void loop() {
65checkEnterButton();
66
67if(digitalRead(modePin)  == LOW)
68{
69  calculateAndDisplayFlow();
70  checkUpDownButtonCount();
71}
72else
73{  
74  readAndDisplayLevel(); //run subroutine when pump switch is off 
75  }
76}//end  loop
77
78void readAndDisplayLevel()
79{
80  fuelValue = analogRead(fuelPin);
81  level = map(fuelValue, 510, 119, 0, 29); //510 and 119 represent full and empty  levels through voltage divider
82  if(level < 0){                           //29  represent toal number of bars (|) for full on display
83    level =  0;
84  }
85  if(level > 29){
86    level = 29;
87  }
88  gallons = map(fuelValue, 510, 119,  0, 40); //Map same levels to gallon levels in a 40 gallon tank
89  if(gallons <  0){
90    gallons =  0;
91  }
92  if(gallons > 40){
93    gallons =  40;
94  }
95  counter = 0; //set trasfer volume and target back to zero if transfer operation  switched back to fuel level
96  totalMilliLitres = 0;
97  u8g2.sendBuffer();
98  char buffer[32] = "";
99  for(int i=0; i<=level;i++) //this for loop will string  indicator bars together to match level set by mapping tank float resistance 
100   {  
101    strcat(buffer, "|");   
102    }
103  digitalWrite(onPin, LOW);
104  u8g2.clearBuffer();
105  u8g2.setCursor(1, 10); //position display cursor for  first line of text
106  u8g2.setFont(u8g2_font_t0_13_mf); //set font size to 13
107  u8g2.print("Fuel Level Reserve");
108  u8g2.setCursor(2, 30); //position display  cursor for second line of text
109  u8g2.setFont(u8g2_font_helvB08_tf); //set font  size to 11 bold
110  u8g2.print(" E---------1/2---------F");
111  u8g2.setCursor(4,  40); //position display cursor for third line of text
112  u8g2.setFont(u8g2_font_4x6_tf);
113  u8g2.print(buffer); //print the level bars
114  u8g2.setFont(u8g2_font_t0_13_mf);  //set font size to 13
115  u8g2.setCursor(40, 60); //position display cursor for  forth line of text
116  u8g2.print(gallons); //print fuel level in gallons
117  u8g2.print("  Gal.");
118  u8g2.sendBuffer(); //send buffered text to display
119  delay(2000);  
120};//end readAndDisplayLevel
121
122void pulseCounter()  //Measure the number  of pulses for 1 second into pulse counter
123{
124  pulseCount++; 
125}//end pulseCounter
126
127void  checkEnterButton()
128{
129 // read the state of the pushbutton value:
130  enterState  = digitalRead(enterPin);
131
132  // check if the enter button is pressed to start  pump.  Flow sensor will then pulse interrrupt pin 2
133  if (enterState == LOW)  {
134    digitalWrite(pumpPin, !digitalRead(pumpPin));
135    // debounce:
136    delay(300);   
137  }
138} //end checkEnterButton
139
140void calculateAndDisplayFlow() //  if on switch latched, transfer mode screen displayed
141{
142  if((millis() - previousTime)  > 1000)    // Only process counters once per second
143      { 
144        detachInterrupt(sensorInterrupt);
145        digitalWrite(onPin, HIGH);
146        flowMilliLitres = (pulseFactor * pulseCount);  //flow volume (mls) during sampling imperval
147        flowRate = flowMilliLitres/((millis()  - previousTime)/1000); //flow milliliters/sec
148        flowRate = flowRate * 0.016;  // conversion factor to gallons/min.
149        previousTime = millis();
150        totalMilliLitres  += flowMilliLitres;
151        volume = (totalMilliLitres/1000)*gallonFactor;
152        volume = (totalMilliLitres/1000)*.26417; //Convert milliters to Gallons
153        u8g2.clearBuffer();
154        u8g2.setFont(u8g2_font_t0_13_mf);
155        u8g2.setCursor(4,  33);
156        u8g2.print("Target Vol: ");
157        u8g2.print(counter);
158        u8g2.print(" Gal");
159        u8g2.setCursor(4, 50);
160        u8g2.print("Flow:  ");
161        u8g2.print(flowRate,1); // print to one decimal
162        u8g2.print("  Gal/min");
163        u8g2.setCursor(4, 18);
164        u8g2.print("Volume: ");
165        u8g2.print(volume);
166        u8g2.print(" Gal");
167        u8g2.drawFrame(1,1,126,60);  //draw a frame around displayed data
168        u8g2.sendBuffer(); 
169        //  Reset the pulse counter so we can start incrementing again
170        pulseCount  = 0;
171        
172        if(volume >= counter)//turn off pump if pumped volume  is greater than set counted volume
173        {
174          enterState == LOW;
175          digitalWrite(pumpPin, LOW);//turn off pump
176        }
177    
178        //  Enable the interrupt again now that we've finished sending output to display
179        attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
180      }
181}  //end calculateAndDisplayFlow
182
183  void checkUpDownButtonCount() // read the  up and down pins:
184  {
185  byte upState = digitalRead(upButton);
186  byte downState  = digitalRead(downButton)*-1;
187
188  if (upState == 0) {
189    counter++;
190    delay(400);  //delay to prevent bounce from momentary switch
191  }
192  else  if (downState == 0) {
193    counter--;
194    delay(400);
195  }
196  if (counter  < 0){
197    counter = 0;
198  }
199  else if(counter >= gallons) {  //turn off  pump when transferred volume reaches request volume
200    counter = (gallons -  1);
201  }
202} //end checkUpDownButtonCount