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So frustrated with my Hitachi® HM55B Compass Module — Parallax Forums

So frustrated with my Hitachi® HM55B Compass Module

nonameherononamehero Posts: 9
edited 2010-04-19 09:14 in Accessories
This Compass Module is uncalibratable!
I am not using a basic stamp microcontroller, but I don't think that's the problem.
I am able to get the x and y value.
However the x and y value are so unstable that they keep on changing after awhile for no reason at all even when i m staying in the same place, and values even change when i lift the compass up a little bit.
As I spin the compass on my table, the value changing for x and y doesnt even make sense.
the Data sheet says the compass can discern 64 or more angle, how is that possible when the value of my x and y doesnt even change more than 20 values in one 360 spin.

However on this forum, everyone seems to have no problem with it.

I don't understand, am I sitting next to a moving magnet field or something.
please help.

Post Edited (nonamehero) : 11/13/2009 2:13:11 AM GMT

Comments

  • FranklinFranklin Posts: 4,747
    edited 2009-11-13 02:10
    If it is not the right part you should see if you can return it. As you said others don't have problems so it probably is how you have it connected or the program you are trying to run. Check out the site for the processor you are using.

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    - Stephen
  • James LongJames Long Posts: 1,181
    edited 2009-11-13 02:44
    First,

    I would ask do you have any large metallic objects close? Magnetic objects can affect a compass module. Even large non magnetic object can affect the compass module.

    The compass values will change in motion. Any tilt and the value will change.

    Are you sure you are actually talking to the unit, or could you be getting some kind of garbage input?

    I noticed in the BS2 program the results from the compass module is a word variable.

    Also there is a specific routine to get the data out, by the BS2 programming.

    Each time they go to get the information they Reset, start the measurement command, and do not get the values until the ready is relayed. Then they get the values.

    Could this possibly be a programming sequence issue?

    You said, you are not using a BS2. Could it possibly be your version of the communications is faulty?

    I'm not saying it is. I'm just asking to see if you think there is a possibility.

    James L

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    James L
    Partner/Designer
    Lil Brother SMT Assembly Services

    Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!
  • nonameherononamehero Posts: 9
    edited 2009-11-13 03:24
    James Long said...
    First,

    I would ask do you have any large metallic objects close? Magnetic objects can affect a compass module. Even large non magnetic object can affect the compass module.

    The compass values will change in motion. Any tilt and the value will change.

    Are you sure you are actually talking to the unit, or could you be getting some kind of garbage input?

    I noticed in the BS2 program the results from the compass module is a word variable.

    Also there is a specific routine to get the data out, by the BS2 programming.

    Each time they go to get the information they Reset, start the measurement command, and do not get the values until the ready is relayed. Then they get the values.

    Could this possibly be a programming sequence issue?

    You said, you are not using a BS2. Could it possibly be your version of the communications is faulty?

    I'm not saying it is. I'm just asking to see if you think there is a possibility.

    James L

    hi, i m pretty sure it is communicating with the unit, or else the x and y values wont change when i move the compass.
    I doubt the compass is capable to even output other garbage outputs.
    It seems to be pretty straight forward in the datasheet.

    And yah, one of my partner is very good at programming, did the logic for reset, start measurement command and everything.
    Cant be 100% it is correct, but it seems correct, if the programming is wrong, i still dont see how we can be getting any value at all.

    I am not sure, maybe it is the code, but it seems like this compass just doesnt work.

    ·
  • James LongJames Long Posts: 1,181
    edited 2009-11-13 03:45
    nonamehero said...
    hi, i m pretty sure it is communicating with the unit, or else the x and y values wont change when i move the compass.
    I doubt the compass is capable to even output other garbage outputs.

    It seems to be pretty straight forward in the datasheet.



    And yah, one of my partner is very good at programming, did the logic for reset, start measurement command and everything.

    Cant be 100% it is correct, but it seems correct, if the programming is wrong, i still dont see how we can be getting any value at all.



    I am not sure, maybe it is the code, but it seems like this compass just doesnt work.

    What I'm thinking is that the response you're seeing is not actual data, but more of a status code, or partial data.

    The HM55 is pretty slow to respond by the code I've looked at, and a different processor maybe trying to get the data too fast.

    Have you looked around to see if there is anyone else who has used your processor with the HM55B from Parallax?

    I looked and found quite a few different programs for several different sources, for different processors. You may want to try that, just to insure the unit is faulty.

    James L

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    James L
    Partner/Designer
    Lil Brother SMT Assembly Services

    Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!
  • blankkblankk Posts: 15
    edited 2010-04-19 09:14
    Im using an arduino microcontroller and i also cant get the compass to work as it should be
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