[TowerTalk] P3020-V1-CW360 - Hall sensor

[David Gilbert]

Very interesting!  That looks like a very elegant approach.

I am trying to do something similar because I don't want to have to 
replace the linear potentiometer in my PST-71D, except that I am 
planning to use 18 discrete Hall Effect switches (A3144-type)arrayed in 
a circle around the mast (mounted to the underside of the plate above 
the rotator) ... triggered by a single magnet mounted to the mast.  I 
can arrange the Hall Effect switches so that the magnet always activates 
at least one switch, and when it is between switches it activates two of 
them ... which I can interpolate via the Arduino to give me azimuth in 
ten degree increments.   Using a 74HC4067 16-1 multiplexer reduces the 
wires needed between the tower and the shack.  The electronics works 
fine on my workbench ... now I need to 3D print a suitable container for 
the switches (two half circles that I can just wrap around the mast).

The description for the P3020-V1-CW360 specifically says that it has no 
dead spaces, so I'm wondering if the voltage that you are feeding from 
the Hall Effect potentiometer to the Arduino somehow caps out higher 
than it can analogRead.  Are you applying the 5 volts to the Hall Effect 
potentiometer from the Arduino, or from a separate 5 volts supply that 
might not really be 5 volts?  You have probably already checked that, 
but just in case ...

My other thought is that maybe somehow your code isn't handling the full 
0-1023 range.  I am no expert at all (although my oldest son definitely 
is), but if you want to send me a copy of your code I'll try to take a 
look at it to see if I can spot anything. AB7Echo at gmail.com

Best of luck!

73,
Dave   AB7E



On 3/19/2023 1:06 PM, HA3LN wrote:
> Dear Members,
>
> Does anyone know/use any of these 2x type of Hall sensors?
>
> P3020-V1-CW360
> P3022-V1-CW360
>
> https://ha3ln.hu/?p=2801
> (pics and short video clips about the problem)
>
> I'm about to renew my old rotator system with an Arduino based 
> controller where the azimuth sensor meant to be this Hall sensor.
> Gives 5Volts output which is greatly matches to the Arduino analog 
> input levels.
>
> These sensors are advertised like 360 degree with "no dead angle" but 
> it seems there are ~45 degrees where no change in output voltage is 
> visible.
> So the full 360deg rotation is mapped into ~315 degrees.
>
>
> I'm wondering whether is this the proper operation and my 
> interpretation of "360 no dead angle" fools me?
>
> I don't see any option to calibrate on the housing. I have 3-3 pieces 
> of each types and all 6 works similarly.
>
>
> Thanks.
>
> 73!
> Csaba  HA3LN
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