FreeIMU GUI

[martinferris]

EDIT: Solved connection problem. Managed to connect to the bluetooth serial port. But how do I access the USB com port?

I'm using the MPU9150_AHRS sketch and want to understand why there is a lot of drift before finding the IMU's absolute position between movements. I have calibrated the magnetometer value as advised in the comments, but I'm still getting a lot of drift before the IMU settles after movement.

I'm using an MPU9150 on a Nano Atmega328 and am pretty new to Arduino stuff so any help would be greatly appreciated, thanks!

[mjs513]

Hi Martin

Sorry for the delay in getting back to you - I haven't used a Nano before so I assume it works the same as all the other Arduino boards. Make sure you connect the Nano to usb port, get the COM# and use that in the GUI. Just remember you have to send the data to the serial port and the Bluetooth - not sure how you have that set up - usually its through telling the Arduino to send to SerialX instead of Serial. As for your drift issue make sure you have the 9150 board selected FreeIMU.h file - uncomment board and make sure you comment out all others. See what you get. If you are still getting a lot of drift try using Marg = 1 or Marg =4. If still you may have to tweak the tuning factors in the FreeIMU.h file. Make sure you call both the accel and mag.

Good Luck Mike

[martinferris]

Hi Mike,

No problem at all, thanks for getting back to me. I'll give all those a shot, but I'm in the process of trying to get the GUI working.

Unfortunately I only have 30kb of memory on the Nano Atmega328 given to me on this project so I'm trying to slim down the FreeIMU_serial_ARM_9150_3115A2 sketch. I'm looking through the cal_gui.py to see what functions are called from the IMU to see how much of the sketch i can cut out.

[martinferris]

Hi Mike,

I've managed to cut down the FreeIMU_serial_ARM_9150_3115A2, however global variables use 1,902 bytes (92%) of dynamic memory, leaving 146 bytes for local variables. When I run it, the nano seems to get stuck in the init() function. I have investigated the FreeIMU.cpp file, and everything seems to make sense but I can't figure out why it's getting stuck in that loop.

Any ideas?

[martinferris]

Must've been the lack of memory! Switched the Marg to 3 and the resulting dynamic memory used was only 67%.

Thanks again for your help Mike, it's greatly appreciated :)

[mjs513]

Yeah thats the way it sounds. You can try 4 as well which is a dcm implementation. Good luck