Calibrating the HMC6352 Compass...

CumQuaT

I've calibrated this thing a few times now, but it still will make jumps of 10 or 15 units at certain points during its rotation. They're consistent, too. I'll get the readings as I slowly turn, and it goes something like:

76, 77, 78, 79, 91, 92, 93, 94... etc

Anyone had this experience? There is nothing metal or magnetic near it...

deaks

I have 2 that are doing the same thing. I suspect that during calibration, I tilted it and the EEPROM got loaded with bad data. I also found that this module is terrible as far as tilt goes. A 10 degree tilt changes the heading by 30 degrees. Way too unstable except for the most level applications. Time to look for a different one. I used the HM55B before and it was pretty good, but it stopped working and seems to be obsoleted. I think I'll try the LSM303DLH next.

deaks

I guess I was premature with my prior post. The problem is the Parallax software. There is a bug with the I2C timing and memory read. See: http://forums.parallax.com/showthread.php?130937-Help-with-hmc6352-compass-module.-Is-this-normal&p=1015256#post1015256

Bill Henning

Hi,

I fixed that bug as I use HMC6352's on some of my RoboProp based bots, however as my obex account does has not worked since the forum upgrade, I could not upload my fix to OBEX.

I am attaching it here... enjoy!

Bill

deaks wrote: »

I guess I was premature with my prior post. The problem is the Parallax software. There is a bug with the I2C timing and memory read. See: http://forums.parallax.com/showthread.php?130937-Help-with-hmc6352-compass-module.-Is-this-normal&p=1015256#post1015256