Poor Mans Vario

//**********************************
//*          BMP280 version        *
//**********************************
// This is the Poor Mans Vario code for the BMP280 sensor by BOSCH Sensortec
// connect BMP280 to .........
// Servo signal input, connect to Arduino pin D3
// Audio output to transmitter on pin D2
// V1 Hans Meijdam, April 2016:
//
//  ****** This is a customizable variable that acts as a switch *****
// choose "1" if you also want to hear the altitude in meters if you fly below 100 meters.
// choose "0" if you only want to hear the 10 meters rounded altitude at all times.
// Default is 0.
const byte altitude_per_meter = 0; // only altitude in 10 meters
// const byte altitude_per_meter = 1; // altitude in whole meters if below 100 meters


//  ****** This is a customizable variable (0 - 500 range) that defines how large the dead band is ******
// A dead band of "0" (= default) means that the vario will beep constantly, even with no climb or sink at all.
// A small dead band (e.g. value 25 - 50) means that with a small amount of climb or sink the vario will start beeping
// A medium dead band (e.g. value 50 - 100) means that the vario will be silent, unless it observes a medium rate of climb or medium rate of sink.
// A high dead band (> 100) makes the vario only active at high rates of sink or climb.
int deadband = 0;  // no deadband or deadband defined by potmeter
// int deadband = 25;  // small deadband
// int deadband = 75;  // medium deadband
// int deadband = 150;  // large deadband

//  ****** Alternatively the deadband can be dynamically set by connecting a 10K potmeter over pins 12, A1 (rocker) and A2 ******
// const byte deadbandpotmeter = 0;  // no deadband potmeter present
const char deadbandpotmeter = 1;  // deadband potmeter is present (10K potmeter over pins 12, A1 (rocker) and A2)

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BMP280.h>

#define BMP_SCK  6 // SCK/SCL on BMP280
#define BMP_MISO 9 // SDO     on BMP280
#define BMP_MOSI 7 // SDA/SDI on BMP280
#define BMP_CS   8 // CSB     on BMP280
#define BMP_GND  5 // GND     on BMP280
#define BMP_VCC  4 // VCC     on BMP280

//Adafruit_BMP280 bme; // I2C
//Adafruit_BMP280 bme(BMP_CS); // hardware SPI
Adafruit_BMP280 bme(BMP_CS, BMP_MOSI, BMP_MISO, BMP_SCK);

const byte led = 13; // define pin that has a led connected to it
const byte audiopin = 3; // define the pin the audio signal is provided to
const byte servopin = 2; // define the pin the servo signal is connected to
unsigned long time = 0;
float toneFreq, toneFreqLowpass, flpressure, lowpassFast, lowpassSlow ;
float p0; // this will be used to store the airfield elevation pressure
int altitude;
int ch1; // Here's where we'll keep our channel values
int ddsAcc;
int analogpin1 = 0;

void setup()
{
 // Wire.begin();
 
  pinMode(BMP_GND, OUTPUT);
  pinMode(BMP_VCC, OUTPUT);
  digitalWrite(BMP_GND, LOW); //Provide GND to BMP280
  digitalWrite(BMP_VCC, HIGH); //Provide 3,3v to BMP280
  delay (100);
  pinMode(servopin, INPUT_PULLUP); // Set servopin input enabling altitude command input from receiver
  pinMode(audiopin, OUTPUT); // set audiopin as output
  pinMode(A2, OUTPUT); // Prepare for high end of potmeter
  pinMode(12, OUTPUT); // Prepare for low end of potmeter
  pinMode(A1, INPUT_PULLUP); // Prepare for potmeter input
  digitalWrite(A2, HIGH); // High end potmeter to 5 volt
  digitalWrite(12, LOW); //Low end potmeter to 0 volt
  Serial.begin(9600); // start serial for output
  analogpin1 = analogRead(1);    // read the input pin A1 potmeter value
  Serial.print("Analog pin A1 value: ");
  Serial.println(analogpin1);
  Serial.println("Setting up BMP280");
  if (!bme.begin()) {
    Serial.println("Could not find a valid BMP280 sensor, check wiring!");
    while (1);
  }
  delay(250);
  flpressure =(bme.readPressure());// get field pressure and move into float type
  p0 = lowpassFast = lowpassSlow = flpressure;
  Serial.print(" p0 = ");
  Serial.println(p0);
}

void loop()
{
  flpressure = (bme.readPressure());// move long type pressure into float type flpressure
  altitude = (float)44330 * (1 - pow(((float) flpressure/p0), 0.190295));
  altitude = abs(altitude); // if flying from hills negative altitude becomes indicated as positive
  lowpassFast = lowpassFast + (flpressure - lowpassFast) * 0.2;
  lowpassSlow = lowpassSlow + (flpressure - lowpassSlow) * 0.1;
  toneFreq = (lowpassSlow - lowpassFast) * 50;
  toneFreqLowpass = toneFreqLowpass + (toneFreq - toneFreqLowpass) * 0.1;
  toneFreq = constrain(toneFreqLowpass, -500, 500);
  ddsAcc += toneFreq * 100 + 2000;

  if (deadbandpotmeter == 1)
  {
    analogpin1 = analogRead(1);    // read the input pin A1 potmeter value
    deadband = map(analogpin1, 0, 1024, 500, 0); // map potmeter value to deadband range from 500 - 0
  }

  if (toneFreq < 0 || ddsAcc > 0)
  {
    if (abs(toneFreq)>deadband)
    {
      tone(audiopin, toneFreq + 550);
      ledOn();  // the Arduino led will blink if the Vario plays a tone, so you can test without having audio connected
    }
  }
  else
  {
    noTone(audiopin);
    ledOff();
  }
  int ones = altitude%10;
  int tens = (altitude/10)%10;
  int hundreds = (altitude/100)%10;
  int thousands = (altitude/1000)%10;
  ch1 = pulseIn(servopin, HIGH, 25000); // Read the pulse width of servo signal connected to pin D3
if((map(ch1, 1000,2000,-500,500)) > 0) // interpret the servo channel pulse, if the Vario should beep altitude or send vario sound
  {
    noTone(audiopin); // create 750 ms of silence, or you won't hear the first altitude beep
    ledOff();
    delay(750);

    if(hundreds == 0)
    {
      tone(audiopin,900);                //long duration tone if the number is zero
      ledOn();
      delay(600);
      noTone(audiopin);
      ledOff();
    }
    else
      for(char a = 0; a < hundreds; a++)          //this loop makes a beep for each hundred meters altitude
      {
        tone(audiopin,900); // 900 Hz tone frequency for the hundreds
        ledOn();
        delay(200);
        noTone(audiopin);
        ledOff();
        delay(200);
      }
    delay(750);                            //longer delay between hundreds and tens

    if(tens == 0)
    {
      tone(audiopin,1100);                //long pulse if the number is zero
      ledOn();
      delay(600);
      noTone(audiopin);
      ledOff();
    }
    else
      for(char a = 0; a < tens; a++)          //this loop makes a beep for each ten meters altitude
      {
        tone(audiopin,1100); //1100 Hz tone frequency for the tens
        ledOn();
        delay(200);
        noTone(audiopin);
        ledOff();
        delay(200);
      }

    if (altitude_per_meter == 1 && hundreds == 0)
    {
      delay(750);                            //longer delay between tens and ones

      if(ones == 0)
      {
        tone(audiopin,1300);                //long pulse if the number is zero
        ledOn();
        delay(600);
        noTone(audiopin);
        ledOff();
      }
      else
        for(char a = 0; a < ones; a++)          //this loop makes a beep for each meter altitude
        {
          tone(audiopin,1300); //1300 Hz tone frequency for the ones
          ledOn();
          delay(200);
          noTone(audiopin);
          ledOff();
          delay(200);
        }
    }
  }
}


void ledOn()
{
  digitalWrite(led,1);
}


void ledOff()
{
  digitalWrite(led,0);
}

#include <Wire.h>

void setup() {
  Serial.begin (9600);

  // Leonardo: wait for serial port to connect
  while (!Serial)
    {
    }

  Serial.println ();
  Serial.println ("I2C scanner. Scanning ...");
  byte count = 0;
 
  Wire.begin();
  for (byte i = 1; i < 120; i++)
  {
    Wire.beginTransmission (i);
    if (Wire.endTransmission () == 0)
      {
      Serial.print ("Found address: ");
      Serial.print (i, DEC);
      Serial.print (" (0x");
      Serial.print (i, HEX);
      Serial.println (")");
      count++;
      delay (1);  // maybe unneeded?
      } // end of good response
  } // end of for loop
  Serial.println ("Done.");
  Serial.print ("Found ");
  Serial.print (count, DEC);
  Serial.println (" device(s).");
}  // end of setup

void loop() {}