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#4108116 - 04/18/15 07:00 AM Re: DIY hall sensor ... [Re: f15sim]  
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tirta Offline
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tirta  Offline
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Hi Brandano,

Thanks for the reply.
Yes, I am aware that HALL sensor can not reach the full range.
But I have used HALL with 2 of my joysticks,
and on one of them I can get rather the sensor values rather close to full range:

x axis: 96 - 4068
y axis: 100 - 4060
this is with A1302.

Using this joystick with the current mmjoy is very precise,
and when testing it in joy-tester after I calibrate it,
I find the values are stable, they do not change.


However, on my other joystick, the one that I change to S495A,
I only get around:
x axis: 300 - 3800
y axis: 300 - 3800

With this values, mmjoy does not seem can use it correctly.
Even after I calibrate it, the maximum and minimum values always get smaller after a while,
like I write here:
http://SimHQ.com/forum/ubbthreads.php/topics/4092126/Re:_MMJoy_-_Build_your_own_USB#Post4092126
http://SimHQ.com/forum/ubbthreads.php/topics/4093559/Re:_MMJoy_-_Build_your_own_USB#Post4093559

If I understand correctly,
using HALL sensor with less than full range should not be a problem with mmjoy,
since values get stretched to 0-4096 after calibration.

However with the second joystick,
after calibration, the stretched value is 0-4096 for a while,
then after I move the stick,
the values always decrease, like this:

first, just after calibration: 0 - 4096 (perfect!).
then, after a few moves : 100 - 4096 (it started to change)
then, move it a few more : 200 - 3900 (more changes)
then, move it a few more : 400 - 3700 (more changes)
(this is an approximation since the real value always changes a little bit)

so the max and min values always changes,
but it is getting smaller all the time.

it might be a bug with mmjoy?
or there is something wrong with the sensor or my setup?





Inline advert (2nd and 3rd post)

#4108228 - 04/18/15 01:42 PM Re: DIY hall sensor ... [Re: f15sim]  
Joined: Aug 2007
Posts: 293
Brandano Offline
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Brandano  Offline
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Caput Mundi (well, it used to ...
I think this might be a case of temperature drift. As the current starts flowing through the sensor its temperature starts slowly to rise, changing the response over time. The best way to check if this is the case would be to monitor its output with a voltmeter. in this case there's little that c an be done other than re-calibrating with he circuit in its warm state. I never had this problem with the allegro, but I generally leave the joystick plugged in even if not in use.

#4108271 - 04/18/15 03:15 PM Re: DIY hall sensor ... [Re: f15sim]  
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tirta Offline
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tirta  Offline
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Yes, I leave my joystick plugged all the time too.

But it is still strange since the the changing sensor values only affect one joystick,
the other is super stable all the time.

I forget to tell you that before I can change the HALL sensors to S495A,
I also used Allegro A1302,
and with those, I also get the the same changing sensor values on that same joystick.


#4108306 - 04/18/15 04:46 PM Re: DIY hall sensor ... [Re: f15sim]  
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Sokol1 Offline
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Tirta,

Do you test with Joytester2 to confirm these changes?

http://www.tuttovola.org/index.php?action=downloads;sa=view;down=877

Test exchange - if possible - the X and Y magnets.
Or, more easy, the X an Y axis connections in the controller.

#4108667 - 04/19/15 06:21 PM Re: DIY hall sensor ... [Re: f15sim]  
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tirta Offline
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tirta  Offline
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using joystester2 is harder to see,
but yes, it does gives me the same changing sensor values.

I also try changing the old magnet that I got from dvd player
to a stronger one: 10mm x 10mm x 10mm cube neodymium magnet.

however, with the new one I get lesser values,
do I have to position the HALL sensor further away from the magnet if I use stronger magnet?

#4108671 - 04/19/15 06:41 PM Re: DIY hall sensor ... [Re: f15sim]  
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LocNar Offline
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I've found the 1302 to be the least useful of the Alegro sensors. The sensitivity on them is 1.3mV/Gauss, so take nearly 180 deg of a strong magnet for a full voltage swing, at least with the Bic pen arrangement. The A1301 behaves the same but can use half the magnet, at 2.5mV/Gauss which allowed me to implement some miniaturization.

Here's the post I made a while back about miniature DIY sealed Hall pots (I think of them as gen 2 versions of Gene's), which are easy to make and incorporate into controls projects.

DIY Sealed Miniature Hall Pots, on the cheap!

Since controls don't typically move 180deg, this rules out direct mounting and tends to waste usable range of motion/resolution. Lately I've experimented to good effect with A1324 (5mV/Gauss) and have found them to be most suitable for typical controls, only taking about 90deg for a full swing, allowing direct mounting as well as better utilization of available resolution.

That said, I've never had any problems with drift with any of my Alegro's. I only buy them from reputable dealers (Newark Electronics in my case) however, because I hear ebay and other sources are full of sub-par counterfeits.


Last edited by LocNar; 04/19/15 06:43 PM.
#4108746 - 04/19/15 10:22 PM Re: DIY hall sensor ... [Re: tirta]  
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Sokol1 Offline
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Originally Posted By: tirta
using joystester2 is harder to see,
but yes, it does gives me the same changing sensor values.


OK. Using Joytester2 you eliminate problem with JoySetup embed tester.

Quote:

I also try changing the old magnet that I got from dvd player
to a stronger one: 10mm x 10mm x 10mm cube neodymium magnet.

I suggest exchange mangetes or axis connections to isolate problem with magnets - a squad mate owner or X-52 notice that one of his magnets became rush and dont work properly. Replace the magnet solve the problem.

Quote:

however, with the new one I get lesser values,


If you still have issues, after exchange axis connection in Arduino board - for confirm that the problem is related with board input and not with HALL/Magnet assembly, rest the board as source of the problem, they can be defective.

These DIY HALL assembly involve a lot of (tedious) magnets positions experimentation/test. smile

I have a case in Suncom conversion that the axis became inverted. smile

My next try will be with this TLE.. sensor, despite the PCB building need, looks more "PnP. wink


#4108889 - 04/20/15 08:05 AM Re: DIY hall sensor ... [Re: f15sim]  
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tirta Offline
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tirta  Offline
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Posts: 464
@LocNar
I have never tried other variants of Allegro.
A1302 is the only one that I can find in my local store.
So I have used it in 2 of my joystick and on one of them is very good.

I will try looking for A1301 and A1324.
Thanks for the information.


@Sokol1
Yes I have tried changing the magnet and the sensor, and the problem remains.
now I will try changing the axis pin on the arduino board.

Can I know what sensor values do you get from your setting?

#4287146 - 08/13/16 01:07 AM Re: DIY hall sensor ... [Re: f15sim]  
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Sokol1 Offline
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