Hello all,
I'm rather new to Arduino and I am working on my first project. I want to build a very basic altimeter however, I am having difficulty finding a suitable unit. I just want a simple device that will measure my elevation above sea level. This project is eventually going to be my altimeter for hiking.
Like I said, I'm very new to this. Any help would be greatly appreciated!
--hiremenow
This is a nice little pressure sensor board with high accuracy and works with either 3.3 or 5 V Arduino. Pololu - LPS331AP Pressure/Altitude Sensor Carrier with Voltage Regulator Pololu provides sample programs as well. SparkFun also has some offerings, but a unique feature of the LPS331 sensor from Pololu is the two programmable pressure alarm outputs.
Although the code provided by Pololu can calculate your altitude from the pressure reading, it assumes a standard atmosphere model and does not offer the opportunity to correct for changes in sea level barometric pressure (the reference altitude). You will need that for hiking, so consider it to be an interesting challenge.
Hi, the adafruit BMP085 is also a pressure unit you could try, adafruit have some good sketches for it and they include altitude calculation.
Tom.... 
I guess you will do several projects down the road.
Try search om ebay for "9DOF" / "10DOF"
several functions will be handy for future use