[TowerTalk] P3020-V1-CW360 - Hall sensor

[Lux, Jim]

On 3/19/23 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)

Traditional pots only swing 315-320 degrees so maybe they're talking 
about that some rotators have a gearing arrangement (or properly sized 
belt pulley) to turn 360 of antenna rotation into 315 degrees of pot 
rotation. The other technique is to use a multi turn pot, but I've only 
seen 3 and 10 turn pots, so 360 degrees turns into about 1/3 of the 
resistance or 1/10th of the resistance range.





>
> 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.


It depends on how many bits are they using - Arduinos have 8 bit, 12 
bit, and 16 bit inputs (depending on specific models). Typically, the 
software turns some range of ADC values into 0-360. If it's an 8 bit 
converter, that's only 256 steps, and if a pot is set up with some 
resistors on either side (so it doesn't swing quite 0 to 5 V.. 1-4V is 
really common, to avoid "too close to rail" issues) then you only wind 
up with 2 degree (or so) steps.

>
> 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.


If you hook a volt meter up to the sensor, and put the supply voltage on 
it, what do you get as you turn the shaft?


What readout electronics are you using? which arduino and which software.

>
>
> Thanks.
>
> 73!
> Csaba  HA3LN
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