I’m currently working on a research project which involves triggering a relay at a certain altitude on a weather balloon. What I am currently using as an altimeter is a BMP180 Barometric Pressure Temperature and Altitude Sensor, as well as this tutorial and library. I currently have my Arduino Uno wired up to the BMP 180, as well as an LCD display to show the results. However, though the sensor does seem to read the temperature and barometric pressure of the surrounding area, the “pressure.altitude(P,p0);” always returns the initial given altitude. I have gone to different altitudes with the sensor and Arduino still running to see if the value would change, but it never did. Am I doing something wrong? What else can/should I try?
Note: The only changes I have made to the code are the inclusion of the LiquidCrystal library, a reduction of the delay between readings to once every 0.25 seconds, and simple print functions to output the values of P, p0, and a to the display. I have attached my .ino file as well.
alt_test.ino (4.19 KB)