Hello,
I am having trouble using this library with Particle Core: https://github.com/pkourany/Adafruit_9DOF_Library with the PitchRollHeading example. We used this library for a hackathon project a few months ago, but we are trying to rebuild our product now and having some trouble because everytime we add the library the Core breaths green. We had this working a few months ago. Could our issues be due to a firmware update?
@horatiothomas, if you are recompiling on the new Core firmware, many things have changed which may affect your application. The breathing green indicates the Cloud connection has been dropped and this is caused by code not allowing the background process to run. You will need to post your application code for me to advise you on whether the issue is in the libraries or your code. 
@peekay123 Thanks for the response!! I am actually just running your unmodified example here: https://github.com/horatiothomas/Adafruit_9DOF_Library/blob/master/examples/pitchrollheading/pitchrollheading.ino, and I am getting the error.
@horatiothomas, you’re going to have to give me a little more info! Like what messages are you getting on the serial port? When does the Core go into blinking green and did it start out connecting to the cloud. The more info, the better I can help!
The following is the only message I am getting from the serial port: “Adafruit 9 DOF Pitch/Roll/Heading Example”, however I am not sure if our IMU is connected properly. The core connects to the cloud briefly and then starts breathing green. Please don’t hesitate to let me know if you need more information.
@horatiothomasm, can you give me details on your hardware, any links to the devices, ect.
We are just using a Particle Core connected to an Adafruit 9-DOF IMU, but even if we disconnect it from the IMU we still get the same problem.
Hey if you need any other information, can you let me know? Also if you think you have an idea of what the issue is can you point us in the right direction, so I can mod the library?
@horatiothomas, which version of the firmware are you compiling the code to in the IDE. Based on the message you saw via Serial, it looks like the I2C is not responding when the devices are being initialized. Can you post a picture of your setup and have you checked your wiring carefully? How are you powering the breakout?