MPL3115A2 Pressure Sensor giving new altitude with reset

Hello Forum,

First time on here but I’m excited to see what all I can learn from some more experience folks.

Im making an altimeter/DAQ board for a high power rocket and am currently working on setting up the altimeter using the spark fun MPL3115A2.

I have the sensor connected as per spark funs set-up tutorial and have the temperature and altitude from the sensor being output on an attached LCD screen.

My only problem with the system right now is that the altitude is terribly off but the temperature is correct nearly every time. When I power cycle the system the altitude will stay constant at a wrong value but then I can come back a few days later after its been sitting on my desk and power on to find a different value being reported. Im currently at approximately 350’ above sea level and the sensor has reported correctly before but sometimes will jump to as high as 550’ and then down to 160’ and in-between.

Has any one seen anything like this or have any thoughts on what I could try to remedy the problem?

Thank you,