Why do Hall thumbsticks for xbox controllers have 2 different types of sensors?

[shoulders]

Hi


On a 1708 Xbox controller it is my understanding that both potentiometers on a stick are 10.3k Ohm so why are the Hall Sensor thumbsticks supplied with 2 types of sensor?

Images from AliExpress listings

Thanks

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[RDC]

Instead of a direct answer, lets get some neurons firing....

Look at the second picture here - https://acidmods.com/forum/index.php/topic,44714.0.html

Then look at the fourth picture here - https://acidmods.com/forum/index.php/topic,43981.0.html

Just pick say the Left stick of each board, and tell me what you notice. Besides it being rotated 90 degrees, that's not it.

[shoulders]

This assumes you mean the left stick as the user when the controller is assembled.
 
the things I notice are:

• In the middle there are 2 extra connections on the playstation
• in the xbox the placement of the stick is offset to the other
• The left stick is near some RF shield stuff, possibly the bluetooth IC

[RDC]

The Left stick is still the Left stick no matter how you hold the controller.

Same number of connections, 14, you're looking at the Rumble motor pads on the DS5 is all there.

Offset does not matter.

Has nothing to do with anything near them, but some of the 14 connections themselves...

[shoulders]

On the Xbox controller the left stick POT are connected by Via to C22 and C20 on the underneath. I  guess this is a capacitor for smoothing (I am a bit rusty).

There is the 304 device (I want to say mosfet but I suspect this is wrong)

The only thing I can think of is how the POTs are grounded to prevent interference.

On the PlayStation board the POT don't seem to be connected the same as each other whereas the ones on the Xbox seem to be connected in a similar manor to each other.

One last thing, when you use Hall sensors, these will convert kinetic energy into electrical energy in the circuit where as POT will just generate resistance.

On the Xbox I think each of the thumbstick inputs are sent to a locallzed digitiser and then this signal is sent to the main controller whereas the playstation go straight to a single controller chip (ALC1016)

Have I got any closer 

[RDC]

The 304 is the Hall sensor for the Trigger on the XB1 controller.

Both controllers stick signals pretty much go right to the MCU.

Both stick types convert kinetic into electrical. One is just a voltage divider (big hint) the other is a convoluted mess that is technically no better because it's still subject to the same wear and tear on the moving bits, and when they get sloppy it doesn't matter if it's a potentiometer or a laser doing the measurement, it's going to be off.

I'll give you another big hint. Have you ever put a battery into anything?

[shoulders]

So with the standard POTs the device returns a voltage depending on it's location from 0.1v to 0.9v and 0.v is usually the mid-point and resistance is used to generate this effect.

from ifixit

In a Hall-Effect joystick, the conductive pin (the wiper) is replaced by a magnet, and the resistive contact strip is replaced by a flat conductor (Hall Element) that is sensitive to magnetic fields.

As electrons flow through this material, the magnetic field effectively ?pushes? them to one side of the conductive material or the other depending on the field polarity.

When the joystick is moved, the sensor detects which side electrons were pushed to in the conductive material and interprets this as movement.

My thoughts

POTs would be unaffected by the battery because they work of voltage and resistance which will not suffer from external interference.

You make reference to the battery, and after looking at the orientation of the xbox sticks I can see they are the same so the Hall sensors on the different sticks share the same orientation to the batteries.

So thinking out of the box are the batteries inducing a magnetic field or other interference with one of the Hall sensors because of their orientation to the batteries. In which case the difference between the sensors would be to compensate for this interference.

It cannot be a voltage supply issue because this would affect both Hall sensors equally.

[RDC]

0v is not the mid point. Mid point depends on the sticks AN+ voltage rail. DS5 is 1.8v, so center is 0.9v, XB1 is 3.3v, so 0.165v is center, and both of those are ideal situations. Tolerances in all of that mess means they are never that value exactly, hence why the controllers are calibrated after they are made and swapping sticks can be a real pain. Neither have anything to do with why there are 2 different ones though.

You're way overthinking it, and a Hall sensor is far more than just a magnetic strip, there are quite a bit of electronics in there. The light bulb should come on now

So final clue... What do a battery, an electrolytic capacitor and a typical diode all have in common? It's the same thing those Hall sensors do, and why there are 2 different ones

[shoulders]

an electrolytic capacitor and a typical diode = current will only flow in one direction.


The POTs can be used in either direction but the Hall sensors have to be connector the right way around? this would explain the L and R on them.

[RDC]

Close, Polarity is what they all have in common, as installing any of those backwards will result in nothing working at best, or some kind of damage at worst. True a voltage divider (POT) doesn't care which way it goes in there, but if you swap the + and - sides for it, then it would be bass ackwards also.  All of those boards have the same center pin function, but they all do not have the same AN+ (power) and Ground pinout for the sticks.

[shoulders]

Thanks RDC, it has been fun. I am going to re-look over the images so I can see the differences myself.