Altimeter

Guru (talk) 18:03, 12 October 2015 (IST)

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Components/Boards Used

1	Explore Atmega32 for Arduino
2	OLED Display Module 128X64
3	Pressure Sensor - BMP180

Arduino code for Altimeter

	#include <SFE_BMP180.h>
	#include <Wire.h>
	#include <SPI.h>
	#include <Adafruit_GFX.h>
	#include <Adafruit_SSD1306.h>
	#include <Button.h>
	#include <EEPROM.h>
	#include "EEPROMAnything.h"
	// If using software SPI (the default case):
	#define OLED_MOSI 9
	#define OLED_CLK 10
	#define OLED_DC 11
	#define OLED_CS 12
	#define OLED_RESET 13
	#define BUTTON1_PIN 4
	#define HPA 0
	#define METER 1
	#define DEG 2
	Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
	/* Uncomment this block to use hardware SPI
	#define OLED_DC 6
	#define OLED_CS 7
	#define OLED_RESET 8
	Adafruit_SSD1306 display(OLED_DC, OLED_RESET, OLED_CS);
	*/
	extern uint8_t Font24x40[];
	extern uint8_t Symbol[];
	extern uint8_t Spash[];
	SFE_BMP180 pressure;
	Button button1 = Button(BUTTON1_PIN,BUTTON_PULLDOWN);
	boolean longPush = false;
	int value, etat = 0;
	double QNH, saveQNH;
	double temperature, pression, altitude = 0;
	double baseAltitude, saveBaseAltitude = 0;
	double altiMin = 9999.0;
	double altiMax = 0.0;
	double lastValue = 0.0;
	int eepromAddr = 10;
	#define MAX_SAMPLES 20
	double samplesBuffer[MAX_SAMPLES];
	int indexBfr = 0;
	double averagePressure = 0;
	boolean bufferReady = false;
	int screen = 0; // numero d'ecran
	#define NB_SCREENS 5
	String debugMsg;
	/* ------------------------------------ setup ------------------------------------------ */
	void setup() {
	button1.releaseHandler(handleButtonReleaseEvents);
	button1.holdHandler(handleButtonHoldEvents,2000);
	display.begin(SSD1306_SWITCHCAPVCC);
	// init QNH
	EEPROM_readAnything(eepromAddr, QNH);
	if (isnan(QNH)) {
	QNH = 1013.25;
	EEPROM_writeAnything(eepromAddr, QNH); // QNH standard
	}
	saveQNH = QNH;
	display.clearDisplay();
	display.drawBitmap(0, 0, Spash, 128, 64, 1);
	display.display();
	delay(1000);
	display.clearDisplay();
	display.setTextSize(1);
	display.setTextColor(WHITE);
	display.setCursor(0,0);
	if (!pressure.begin()) {
	display.println("Init fail !");
	display.println("Turn OFF");
	display.display();
	while(1); // Pause forever.
	}
	button1.isPressed();
	screen = 1;
	}
	/* ------------------------------------ loop ------------------------------------------ */
	void loop() {
	char status;
	button1.isPressed();
	// get pressure and temperature and calculate altitude
	status = pressure.startTemperature();
	if (status != 0) {
	delay(status);
	status = pressure.getTemperature(temperature);
	if (status != 0) {
	status = pressure.startPressure(0);
	if (status != 0) {
	delay(status);
	status = pressure.getPressure(pression, temperature);
	if (status != 0) {
	savePressureSample(pression);
	averagePressure = getPressureAverage();
	if (bufferReady) {
	altitude = pressure.altitude(averagePressure*100, QNH*100);
	setAltiMinMax();
	}
	}
	}
	}
	}
	if (etat == 0) {
	// init baseAltitude
	if (baseAltitude == 0) {
	baseAltitude = round(altitude);
	saveBaseAltitude = baseAltitude;
	}
	// calculate QNH
	if (baseAltitude != saveBaseAltitude) {
	QNH = pressure.sealevel(pression, baseAltitude);
	saveBaseAltitude = baseAltitude;
	}
	// Save QNH in EEPROM
	if (QNH != saveQNH) {
	saveQNH = QNH;
	EEPROM_writeAnything(eepromAddr, QNH);
	}
	switch (screen) {
	case 1: // Altitude
	if (lastValue != altitude) {
	showScreen("ALTITUDE", altitude, METER);
	lastValue = altitude;
	}
	break;
	case 2: // Altitude Max
	if (lastValue != altiMax) {
	showScreen("ALTITUDE MAX", altiMax, METER);
	lastValue = altiMax;
	}
	break;
	case 3: // Altitude Min
	if (lastValue != altiMin) {
	showScreen("ALTITUDE MIN", altiMin, METER);
	lastValue = altiMin;
	}
	break;
	case 4: // Pression
	if (lastValue != pression) {
	showScreen("PRESSION", pression, HPA);
	lastValue = pression;
	}
	break;
	case 5: // Temperature
	if (lastValue != temperature) {
	showScreen("TEMPERATURE", temperature, DEG);
	lastValue = temperature;
	}
	break;
	}
	}
	else { // Settings
	// Settings
	display.clearDisplay();
	display.setTextSize(1);
	display.setCursor(0,0);
	display.println("CALIBRATION");
	display.setCursor(0,15);
	display.print("QNH : ");
	display.print(QNH,2);
	display.println(" hPa");
	//display.print("Debug : ");
	//display.println(debugMsg);
	//display.print("Etat : ");
	//display.println(etat);
	if (etat == 1) drawSymbol(100, 40, 3); //UP
	if (etat == 2) drawSymbol(100, 40, 4); // DOWN
	if (value != 0) {
	baseAltitude += value;
	value = 0;
	// recalcule le QNH
	QNH = pressure.sealevel(pression, baseAltitude);
	}
	display.setCursor(0,45);
	display.print("Alti : ");
	display.println(baseAltitude, 0);
	display.display();
	}
	delay(50);
	}
	/* -------------------- fonctions -------------------- */
	// Affiche les données d'un ecran
	void showScreen(String label, double value, int unit) {
	display.clearDisplay();
	display.setCursor(0,0);
	display.println(label);
	drawFloatValue(0, 20, value, unit);
	display.display();
	}
	// Enregistre un echantillon de pression
	void savePressureSample(float pressure) {
	if (indexBfr == MAX_SAMPLES) {
	indexBfr = 0;
	bufferReady = true;
	}
	samplesBuffer[indexBfr++] = pressure;
	}
	// Retourne la moyenne des echantillons de pression
	float getPressureAverage() {
	double sum = 0;
	for (int i =0; i<MAX_SAMPLES; i++) {
	sum += samplesBuffer[i];
	}
	return sum/MAX_SAMPLES;
	}
	// Enregistre les altitudes Min & Max
	void setAltiMinMax() {
	if (altitude > altiMax) altiMax = altitude;
	if (altitude < altiMin) altiMin = altitude;
	}
	void resetAltiMinMax() {
	altiMax = altiMin = altitude;
	}
	// Gestion du bouton relaché
	void handleButtonReleaseEvents(Button &btn) {
	//debugMsg = "Release";
	if (!longPush) {
	if (etat != 0 ) { // Settings
	if (etat == 1) value = 1;
	if (etat == 2) value = -1;
	}
	else { // Change screen
	screen++;
	if (screen > NB_SCREENS) screen = 1;
	lastValue = 0;
	}
	}
	longPush = false;
	}
	// Gestion de l'appui prolongé sur le bouton
	void handleButtonHoldEvents(Button &btn) {
	//debugMsg = "Hold";
	longPush = true;
	screen = 1;
	value = 0;
	if (screen == 1 && ++etat > 2) {
	etat = 0;
	delay(500);
	}
	else if (screen == 2 || screen == 3) {
	resetAltiMinMax();
	}
	}
	// Affiche un caractére en x, y
	void drawCar(int sx, int sy, int num, uint8_t *font, int fw, int fh, int color) {
	byte row;
	for(int y=0; y<fh; y++) {
	for(int x=0; x<(fw/8); x++) {
	row = pgm_read_byte_near(font+x+y*(fw/8)+(fw/8)*fh*num);
	for(int i=0;i<8;i++) {
	if (bitRead(row, 7-i) == 1) display.drawPixel(sx+(x*8)+i, sy+y, color);
	}
	}
	}
	}
	// Affiche un gros caractére en x, y
	void drawBigCar(int sx, int sy, int num) {
	drawCar(sx, sy, num, Font24x40, 24, 40, WHITE) ;
	}
	void drawDot(int sx, int sy, int h) {
	display.fillRect(sx, sy-h, h, h, WHITE);
	}
	// Affiche un symbole en x, y
	void drawSymbol(int sx, int sy, int num) {
	drawCar(sx, sy, num, Symbol, 16, 16, WHITE) ;
	}
	// Affiche un nombre decimal
	void drawFloatValue(int sx, int sy, double val, int unit) {
	char charBuf[15];
	if (val < 10000) {
	dtostrf(val, 3, 1, charBuf);
	int nbCar = strlen(charBuf);
	if (nbCar > 5) { // pas de decimal
	for (int n=0; n<4; n++) drawBigCar(sx+n*26, sy, charBuf[n]- '0');
	drawSymbol(108,sy, unit);
	}
	else {
	drawBigCar(sx+86, sy, charBuf[nbCar-1]- '0');
	drawDot(78, sy+39, 6);
	nbCar--;
	if (--nbCar > 0) drawBigCar(sx+52, sy, charBuf[nbCar-1]- '0');
	if (--nbCar > 0) drawBigCar(sx+26, sy, charBuf[nbCar-1]- '0');
	if (--nbCar > 0) drawBigCar(sx, sy, charBuf[nbCar-1]- '0');
	drawSymbol(112,sy, unit);
	}
	}
	}

view raw Explore Altimeter hosted with ❤ by GitHub

Downloads

• Complete Arduino code

References and Credits

• http://electro.olganet.com/