Acoustic Variometer (Ultra Sensitive Barometer)

1/*
2  This sketch act as Variometer for paragliding, by Marco Zonca,  2020
3  Arduino MiniPro 3.3 as CPU, GY-63 (MS5611) barometric pressure sensor,  8 x dipswitch, buzzer,
4  Mux 4051, lipo 1s 3.7v 350mA, 3.7v -> 5v voltage stepup  + lipo usb charger;
5
6  DipSwitch: 1= not used
7             2= hw low/high  buzzer volume
8             3= \sink alarm: OFF -1.0 -2.0 -3.0 m/sec
9             4=  /
10             5= \frequency beeps: +1.0 +1.5 +2.0 +3.0 Hz
11             6=  /
12             7= \sensibility: +0.0 +0.1 +0.2 +0.5 m/sec
13             8=  /
14 */
15
16#include <MS5611.h>
17#include <NewTone.h>
18
19const int muxIOpin  = 15;
20const int vbattPin = 14;
21const int muxbit0 = 4;
22const int muxbit1  = 5;
23const int muxbit2 = 6;
24const int buzzerPin = 7;
25const int DIPSWinterval  = 5000;
26const int BATTinterval = 10000;
27const int PrexInterval = 500;
28const  boolean isDebug = false;
29
30float sensibility[5];
31float frequency[5];
32float  sinkalarm[5];
33long n=0;
34boolean dipswitch[9];
35String dips;
36unsigned  long prevDIPSWmillis = 0;
37unsigned long prevBATTmillis = 0;
38float n1=0;
39float  n2=0;
40float SensorVBatt=0;
41double referencePressure = 0;
42unsigned long  prevPrexMillis = 0;
43unsigned long currPrexMillis = 0;
44double realPressure  = 0;
45float absoluteAltitude = 0;
46float relativeAltitude = 0;
47float avgAltitude  = 0;
48float avgPrevAltitude = 0;
49long PrexCounter = 0;
50float PrexTotal =  0;
51float PrexVario = 0;
52boolean isFirstCalc = true;
53
54MS5611 psensor;  // pressure sensor
55
56void setup() {
57  Serial.begin(9600);
58  pinMode(muxbit0,  OUTPUT);
59  pinMode(muxbit1, OUTPUT);
60  pinMode(muxbit2, OUTPUT);
61  pinMode(buzzerPin,  OUTPUT);
62
63  sensibility[4]=0;
64  sensibility[3]=0.5;
65  sensibility[2]=0.2;
66  sensibility[1]=0.1;
67  sensibility[0]=0.0;
68
69  frequency[4]=0;
70  frequency[3]=3.0;
71  frequency[2]=2.0;
72  frequency[1]=1.5;
73  frequency[0]=1.0;
74  
75  sinkalarm[4]=0;
76  sinkalarm[3]=-3.0;
77  sinkalarm[2]=-2.0;
78  sinkalarm[1]=-1.0;
79  sinkalarm[0]=-999.9;
80
81  readDIPswitch();
82  psensor.begin();
83  referencePressure = psensor.readPressure();
84  if (isDebug == true) Serial.println("Vario is on");
85  NewTone (buzzerPin,4);
86  delay(750);
87  noNewTone();
88}  // end setup()
89
90void loop() {
91  readPSensor();
92  if ((prevDIPSWmillis+DIPSWinterval) < millis()) {
93    readDIPswitch();
94    prevDIPSWmillis=millis();
95  }
96  if ((prevBATTmillis+BATTinterval) < millis())  {
97    checkBATT();
98    prevBATTmillis=millis();
99  }
100}  // end loop()
101
102void  readPSensor() {  // read Pressure Sensor
103  // Calculate average altitude and  vario
104  realPressure = psensor.readPressure();
105  absoluteAltitude = psensor.getAltitude(realPressure);
106  relativeAltitude = psensor.getAltitude(realPressure, referencePressure);
107  PrexCounter  = PrexCounter + 1;
108  PrexTotal = PrexTotal + relativeAltitude;
109  currPrexMillis  = millis();
110  if (currPrexMillis - prevPrexMillis >= PrexInterval) {
111    avgAltitude  = PrexTotal / PrexCounter; // average
112    if (isFirstCalc == true) {
113      avgPrevAltitude=avgAltitude;
114      isFirstCalc=false;
115    }
116    PrexVario=(avgAltitude-avgPrevAltitude)  * (1000/PrexInterval);  // vario mSec
117    if ((PrexVario <= sensibility[4]) &&  (PrexVario >= sinkalarm[4])) {
118      noNewTone();
119    }
120    if ((PrexVario  > sensibility[4])) {  // lift beep beep +
121      NewTone (buzzerPin,((int)(PrexVario+frequency[4])));
122    }
123    if ((PrexVario < sinkalarm[4])) {  // sink beeeeeep -
124      NewTone  (buzzerPin,0.1);
125    }
126    avgPrevAltitude=avgAltitude;
127    prevPrexMillis  = currPrexMillis;
128    PrexTotal=0;
129    PrexCounter=0;
130
131    if (isDebug  == true) {
132      Serial.print("Vario=");
133      Serial.println(PrexVario);
134    }
135
136  }
137}  // end readPSensor()
138
139void readDIPswitch() {  // read  dipswitch 1-8 for settings
140  int s=0;
141  for (n=1; n<9; n++) {
142    dips="0000"+String(n-1,  BIN);  //leading zeros at left, compose 3 bits selection
143    dips=(dips.substring(dips.length()-3,dips.length()));
144    if (dips.substring(2,3) == "0") digitalWrite(muxbit0, LOW);  // port selection  (1-8)
145      else digitalWrite(muxbit0, HIGH);
146    if (dips.substring(1,2)  == "0") digitalWrite(muxbit1, LOW);
147      else digitalWrite(muxbit1, HIGH);
148    if (dips.substring(0,1) == "0") digitalWrite(muxbit2, LOW);
149      else  digitalWrite(muxbit2, HIGH);
150    if (analogRead(muxIOpin) > 512) dipswitch[n]=false;  // read selected port
151      else dipswitch[n]=true;
152    if (isDebug == true)  {
153      if (dipswitch[n]==false) Serial.print("0");
154        else Serial.print("1");
155    }
156  }  // end for
157  if (isDebug == true) Serial.println("");
158  s=0;
159  if (dipswitch[7]==true) s = s + 2;
160  if (dipswitch[8]==true) s = s + 1;
161  sensibility[4]=sensibility[s];
162  if (isDebug == true) {
163    Serial.print("Sensibility=");
164    Serial.println(sensibility[4]);
165  }
166  s=0;
167  if (dipswitch[5]==true)  s = s + 2;
168  if (dipswitch[6]==true) s = s + 1;
169  frequency[4]=frequency[s];
170  if (isDebug == true) {
171    Serial.print("Frequency=");
172    Serial.println(frequency[4]);
173  }
174  s=0;
175  if (dipswitch[3]==true) s = s + 2;
176  if (dipswitch[4]==true)  s = s + 1;
177  sinkalarm[4]=sinkalarm[s];
178  if (isDebug == true) {
179    Serial.print("SinkAlarm=");
180    Serial.println(sinkalarm[4]);
181  }
182}  // end readDIPswitch()
183
184void  checkBATT() {  // check lipo/liion battery voltage
185  n1 = analogRead(vbattPin);
186  n2=(((6.60 * n1) / 1023.00));
187  SensorVBatt=(n2 + ((n2 * 0.0) /100));  // arbitrary  correction (not active = 0.0%)
188  if (SensorVBatt <= 3.4) {
189    NewTone (buzzerPin,6,1000);
190  }
191  if (isDebug == true) {
192    Serial.print("VBatt=");
193    Serial.println(SensorVBatt);
194  }
195}  // end checkBATT()
196
197