Altimeter | Technology Tutorials

In this video lesson we create a portable altimeter that measures altitude above a base reference location. The device uses an arduino uno R4 Wifi, a BMP180 pressure sensor which is on the GY-87 module. For your convenience, we present the circuit diagram used below:

Schematic for the Portable Arduino Altimeter

This is the code for this project, for your convenience.

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_BMP085.h>

Adafruit_BMP085 BP;
bool BMPconnected;
bool haveBase = false;

int butPin = 2;
int butVal = 1;
int butValOld = 1;

float basePressure;
float Height = 0;
float HeightNow = 0;
int feet;
int inches;


int screenWidth = 128;
int screenHeight = 64;
int oledReset = -1;
#define SCREEN_ADDRESS 0x3C
Adafruit_SSD1306 oled(screenWidth, screenHeight, &Wire, oledReset);

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(butPin, INPUT_PULLUP);
  delay(250);
  BMPconnected = BP.begin();
  if (BMPconnected == true) {
    Serial.println("BMP180 Found and Connected.");
  }
  if (BMPconnected == false) {
    Serial.println("BMP180 Not Found! Check Connections.");
  }
  oled.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS);
  oled.clearDisplay();
  oled.setCursor(0, 12);
  oled.setTextColor(WHITE);
  oled.setTextSize(1);
  oled.println("Place the Deluxe ");
  oled.println("HeightOmatic at");
  oled.println("Base Location, and");
  oled.println("Press Go!");
  oled.display();
}

void loop() {
  // put your main code here, to run repeatedly:
  butVal = digitalRead(butPin);
  if (butVal == 1 && butValOld == 0) {
    basePressure=0;
    oled.clearDisplay();
    oled.setCursor(0,12);
    oled.setTextSize(1);
    oled.setTextColor(WHITE);
    oled.println("WAIT . . .");
    oled.display();
    for (int i=1;i<=100;i=i+1){
      basePressure=basePressure + BP.readPressure();
    }
    basePressure = basePressure/100;
    haveBase = true;
  }
  butValOld = butVal;
  if (haveBase == true) {
    HeightNow = findHeight(basePressure);
    Height = .95 * Height + .05 * HeightNow;
    feet = Height;
    inches = (Height - feet) * 12; 
    oled.clearDisplay();
    oled.setCursor(0, 12);
    oled.setTextColor(WHITE);
    oled.setTextSize(1);
    oled.print(feet);
    oled.print(" Ft ");
    oled.print(inches);
    oled.println(" In");
    oled.setTextSize(1);
    oled.println("Place the Deluxe ");
    oled.println("HeightOmatic at");
    oled.println("Base Location, and");
    oled.println("Press Go!");
    oled.display();
    delay(10);
  }
}

float findHeight(float p0) {
  float d;
  float T0 = 288.15;
  float L = .0065;
  float R = 8.3144598;
  float M = .0289644;
  float g = 9.8;
  float pH;
  pH = BP.readPressure();
  float c = R * L / (M * g);
  d = T0 / L * (1 - pow((pH / p0), c));
  d = d * 3.28084;
  return d;
}

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#include <SPI.h>

#include <Wire.h>

#include <Adafruit_GFX.h>

#include <Adafruit_SSD1306.h>

#include <Adafruit_BMP085.h>

Adafruit_BMP085 BP;

bool BMPconnected;

bool haveBase = false;

int butPin = 2;

int butVal = 1;

int butValOld = 1;

float basePressure;

float Height = 0;

float HeightNow = 0;

int feet;

int inches;

int screenWidth = 128;

int screenHeight = 64;

int oledReset = -1;

#define SCREEN_ADDRESS 0x3C

Adafruit_SSD1306 oled(screenWidth, screenHeight, &Wire, oledReset);

void setup() {

// put your setup code here, to run once:

Serial.begin(9600);

pinMode(butPin, INPUT_PULLUP);

delay(250);

BMPconnected = BP.begin();

if (BMPconnected == true) {

Serial.println("BMP180 Found and Connected.");

}

if (BMPconnected == false) {

Serial.println("BMP180 Not Found! Check Connections.");

}

oled.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS);

oled.clearDisplay();

oled.setCursor(0, 12);

oled.setTextColor(WHITE);

oled.setTextSize(1);

oled.println("Place the Deluxe ");

oled.println("HeightOmatic at");

oled.println("Base Location, and");

oled.println("Press Go!");

oled.display();

}

void loop() {

// put your main code here, to run repeatedly:

butVal = digitalRead(butPin);

if (butVal == 1 && butValOld == 0) {

basePressure=0;

oled.clearDisplay();

oled.setCursor(0,12);

oled.setTextSize(1);

oled.setTextColor(WHITE);

oled.println("WAIT . . .");

oled.display();

for (int i=1;i<=100;i=i+1){

basePressure=basePressure + BP.readPressure();

}

basePressure = basePressure/100;

haveBase = true;

}

butValOld = butVal;

if (haveBase == true) {

HeightNow = findHeight(basePressure);

Height = .95 * Height + .05 * HeightNow;

feet = Height;

inches = (Height - feet) * 12;

oled.clearDisplay();

oled.setCursor(0, 12);

oled.setTextColor(WHITE);

oled.setTextSize(1);

oled.print(feet);

oled.print(" Ft ");

oled.print(inches);

oled.println(" In");

oled.setTextSize(1);

oled.println("Place the Deluxe ");

oled.println("HeightOmatic at");

oled.println("Base Location, and");

oled.println("Press Go!");

oled.display();

delay(10);

}

float findHeight(float p0) {

float d;

float T0 = 288.15;

float L = .0065;

float R = 8.3144598;

float M = .0289644;

float g = 9.8;

float pH;

pH = BP.readPressure();

float c = R * L / (M * g);

d = T0 / L * (1 - pow((pH / p0), c));

d = d * 3.28084;

return d;

}

In this video lesson I show you how you can create a project for measuring altitude using an arduino and a BMP180 Pressure Sensor. We go through the physics, math, circuit and coding to make this project work. For our example, we are using a GY-87 module, which has a BMP180 sensor on it. If you are using a BMP180 sensor directly, it should work the same. For your convenience, this is the circuit schematic we will be using:

For your convenience, the code we developed in the video lesson above is included below. Enjoy!

#include <Adafruit_BMP085.h>

Adafruit_BMP085 BP;
bool BMPconnected;
bool haveBase = false;

float basePressure;
float Height = 0;
float HeightNow=0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  BMPconnected = BP.begin();
  if (BMPconnected == true) {
    Serial.println("BMP180 Found and Connected.");
  }
  if (BMPconnected == false) {
    Serial.println("BMP180 Not Found! Check Connections.");
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  if (haveBase==false){
    Serial.println("Place Device at Base, Enter Go:");
    while (Serial.available()==0){

    }
    basePressure=BP.readPressure();
    haveBase = true;
  }
  HeightNow = findHeight(basePressure);
  Height= .95*Height + .05*HeightNow;
  Serial.print(5);
  Serial.print(",");
  Serial.print(-5);
  Serial.print(",");
  Serial.print(HeightNow);
  Serial.print(",");
  Serial.println(Height);

  delay(10);

}

float findHeight(float p0){
  float d;
  float T0 =288.15;
  float L =.0065; 
  float R = 8.3144598;
  float M = .0289644;
  float g = 9.8;
  float pH;
  pH=BP.readPressure();
  float c=R*L/(M*g);
  d = T0/L*(1 - pow((pH/p0), c ));
  d = d * 3.28084;
  return d;
}

#include <Adafruit_BMP085.h>

Adafruit_BMP085 BP;

bool BMPconnected;

bool haveBase = false;

float basePressure;

float Height = 0;

float HeightNow=0;

void setup() {

// put your setup code here, to run once:

Serial.begin(9600);

BMPconnected = BP.begin();

if (BMPconnected == true) {

Serial.println("BMP180 Found and Connected.");

}

if (BMPconnected == false) {

Serial.println("BMP180 Not Found! Check Connections.");

}

void loop() {

// put your main code here, to run repeatedly:

if (haveBase==false){

Serial.println("Place Device at Base, Enter Go:");

while (Serial.available()==0){

}

basePressure=BP.readPressure();

haveBase = true;

}

HeightNow = findHeight(basePressure);

Height= .95*Height + .05*HeightNow;

Serial.print(5);

Serial.print(",");

Serial.print(-5);

Serial.print(",");

Serial.print(HeightNow);

Serial.print(",");

Serial.println(Height);

delay(10);

}

float findHeight(float p0){

float d;

float T0 =288.15;

float L =.0065;

float R = 8.3144598;

float M = .0289644;

float g = 9.8;

float pH;

pH=BP.readPressure();

float c=R*L/(M*g);

d = T0/L*(1 - pow((pH/p0), c ));

d = d * 3.28084;

return d;

}

Making The World a Better Place One High Tech Project at a Time. Enjoy!

Technology Tutorials

Tag Archives: Altimeter

Portable Altimeter Project with Arduino

Measure Altitude with an Arduino Project

Making The World a Better Place One High Tech Project at a Time. Enjoy!