Hall Sensors on Hoverboard question

For those of you who have some insight, I’d like to ask if you know / guess what is the function of these hall sensors on a hoverboard motor.

It’s a Jetson hoverboard. There are three halls on the inside, which are obvious. However, I see three more pointing inwards towards the motor shaft, apparently doing nothing. Any of you have any idea what are these for?

Thank you.


Is it the same on both wheels?

Yes, symmetrical. Both wheels have the same extra 3 sensors.

I’d expect there to be a magnet mounted to the axle, so the inwards facing halls could measure the orientation of the board vs. the wheels…

But maybe it is a case of a sensor board design being used on multiple models of hoverboard, with not always the same configuration in terms of which parts are used?

I didn’t find a magnet on the board.

Perhaps this is a combination of both, the board is for multiple models, and one of the models has a magnet to check on the wheel orientation?

What’s puzzling is that there are only 4 signal wires, for 6 sensors I’d expect 6 signal wires. This is very strange.

I don’t need the hall sensors, since I’m using an angle sensor but I was really wondering why they made it like that.

Thank you.

Strange indeed. It doesn’t looks like they’re positioned accurately enough to do anything useful even if there were signal lines for them and a magnet to sense.

Maybe it simple is for an inrunner motor version, therefore an universal pcb.

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The marked components are labeled ‘2n551’. Might it just be transistors used to amplify the sensor signal?

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I think that’s for measuring the temperature