Go Down

Topic: HMC6352 compass in a vehicle? (Read 950 times) previous topic - next topic

kg4wsv

Has anyone tried using a HMC6352 compass mounted in (or on) a vehicle?  Does it compensate for all that metal, and how bad are the measurements when on an incline?

thanks.

-j


jluciani

You probably want to put the sensor in the front window right above the rear view
mirror. That is where the factory installed sensor is in my vehicle.

The HMC6343 (which has a third axis and accelerometers) does do a good job
at compensating for tilt.

(* jcl *)

kg4wsv

Quote
The HMC6343 (which has a third axis and accelerometers) does do a good job
at compensating for tilt.


I don't doubt it, but even the HMC6352 is more expensive than a cheap GPS; the HMC6343 is well out of the budget for my application right now.

The Garmin GPS units (especially the GPS18) do a pretty good job of maintaining a sane heading indication, even at low speeds or when stopped (got to allow for moving in reverse, though).  I'm not sure the expense ($US50) is even worth it for the HMC6352.

-j


jluciani

The HMC6343 is a lot of money. In the last project I did we needed the compass
and did not have time to develop or evaluate lower priced options. We required
the tilt compensation.

If you want to roll your own checkout the Microchip app-note AN996,
Designing a Digital Compass Using the PIC18F2520 --
http://tinyurl.com/cnnb2x

It looks like a very good note. Should not be too hard to port to ATmega
chips.

Honeywell is coming out with a 3-axis sensor for $40 -- HMC5843
If you added an accelerometer you could be in the $50 range. This was
the chip I was hoping to use in the last project but since it was a 3 week
project I could not wait 6 weeks for a compass ;)

(* jcl *)

kg4wsv

Thanks for the pointers to the app note and the new device.  I'm in no hurry, so it won't kill me to wait for it.  

The app note leads me to believe that the calculations are simpler than I would have guessed.  Not sure why, but I was envisioning some calculus.  :)

-j


Go Up