3-D compasses

Also - forgot to ask one other thing: Does anybody have any idea how much a compass module would be affected by motors nearby? Over last summer I worked on a UAV that had an onboard compass module. The compass was within about 30cm of a motor that was taking, if my memory is serving me correctly, something around 5A at 28V. (but I could be completely off on the amperage there - but it was very high). Amazingly

- the compass still seemed to work ok.

In my application I plan on having a compass module in between 18 motors. All of the 18 will be turning on at different times for different amounts of time. They will be about 10-15cm from the module. They consume about 50-300ma at 6V. Will this be a problem? At first I was thinking that it would be, but then I started thinking about the compass onboard the UAV, and I figure that if it wasn't effected by that huge goliath of a motor, that a bunch of small motors would similarly not have much effect.

What do you all think?

-M. Noone

I believe it was Circuit Cellar which published some articles on this.

Here's a link. Proto boards and sensors.

Honeywell, available from digikey IIRC, $100 per.

I'm currently planning on their 'micromag' board at $50. Their other ones range from about $650-1600, which puts them well out of my price range.

-M. Noone