alt

Adafruit_BME280.cpp

@@ -282,6 +282,18 @@ float Adafruit_BME280::readPressure(void) {
   return (float)p/256;
 }
 
+
+float Adafruit_BME280::readAltitude(float seaLevelhPa) {
+  float altitude;
+
+  float pressure = readPressure(); // in Si units for Pascal
+  pressure /= 100;
+
+  altitude = 44330 * (1.0 - pow(pressure / seaLevelhPa, 0.1903));
+
+  return altitude;
+}
+
 /**************************************************************************/
 /*!
 

Adafruit_BME280.h

@@ -141,8 +141,7 @@ class Adafruit_BME280
     float readPressure(void);
     float readHumidity(void);
 
-    //  float pressureToAltitude(float seaLevel, float atmospheric, float temp);
+    float readAltitude(float seaLevelhPa = 1013.25);
-    // float seaLevelForAltitude(float altitude, float atmospheric, float temp);
 
   private:
 

examples/bme280test/bme280test.ino

@@ -47,11 +47,15 @@ void loop() {
     Serial.print("Pressure = ");
     Serial.print(bme.readPressure());
     Serial.println(" Pa");
+
+    Serial.print("Approx altitude = ");
+    Serial.print(bme.readAltitude(1013.25)); // this should be adjusted to your local forcase
+    Serial.println(" m");
     
     Serial.print("Humidity = ");
     Serial.print(bme.readHumidity());
     Serial.println(" %");
     
     Serial.println();
-    delay(500);
+    delay(2000);
-}
+}