Comments: MPL3115A2 Pressure Sensor Hookup Guide

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  • Hi, with the suggested library, I was wondering if it would be possible to access both the altitude mode and barometer mode in the same sketch? Whenever I use a mode for one object, it overrides all other modes for different objects. I just want to be able to display pressure then altitude sequentially. Is anyone able to give me some suggestions? Thanks!!!

  • I've been using this with an Arduino Mega. The I2C is reading 4.9V, however it won't work with the resistors and actually works fine without them... Any thoughts? I don't want to damage the sensor.

  • Tried a sparkfun and uno board with suggested hookup. Not working. Getting the "Pressure(Pa):-999.00 Temp(f):-1766.20 Altimeter setting InHg:nan" thing. Tried running an I2C scan, and no success.

  • I'm having problems with the Arduino library on Linux. I've got a Weather Shield. (which uses this sensor and the MPL3115A2 library) I successfully built the sample code, and successfully made a few changes to send the readings inside with a set of Xbees. All that was, however, done using a Windows 7 machine. The Windows box is inconvenient for further development. (it's in a room full of ham gear & there's really no space for a set of weather sensors:) ) I have a Linux (Ubuntu) machine in a much larger room.

    But I can't get the code to build on the Linux box. I get a few dozen "MPL3115A2.h:619:9: error: stray ‘#’ in program" errors, and a dozen or two other errors of various types. I've tried re-downloading the library, both from the link on this guide and the one on the WeatherShield guide. (they point to two different URLs) I've tried simply copying the folder from the Windows machine. I've tried running "dos2unix" on the .h and .cpp files in case there was a line-ending disagreement. None of it has worked.

    The Weather Shield also uses the HTU21D humidity sensor. I downloaded that library from the link on the WeatherShield guide & it works fine. (at least, there are no compile errors citing that library)

    Again, the same sketch will build (and run) perfectly if I build it on the Windows box. I'm confused.

  • A friend of mine and I are trying to assemble a weather balloon, and we are using Arduino as a data logger. We bought most of our equipment on Sparkfun, including a pressure sensor (specifically the MPL3115A2). Following the instructions, we used the Sparkfun guide to hook up the sensor to the board, and used a template program on the website to run the sensor. We first used two resistors, then tried a level translator from sparkfun. Neither worked, if you have any questions for clarification please let me know. However, when watching the data log we were getting pressure and altitude readings of -999.99. This is clearly something we are doing wrong, and we are wondering if you guys have any ideas. On the website it says this is an "I2C timeout (512ms max)." What does this mean? Any ideas on how to fix it? Thanks

    • There have been a few discussions on the product page as well so be sure to check there. It's hard to say.

      What board are you hooking the sensor to? What voltage?

      What inline resistors (if any) are you using? The tutorial recommends 10ks but depending on what you're hooked to you might try 330s inline.


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