Speedometer motor

[Graham RounceParticipant @grahamrounce14492]

Michael G – A little beaut. I’m of the age that the breathtaking micro-mechanics of things like this make me want to have them!, regardless of wtf I could use them for!  🙂   And the price, yes! There’s a lot of that on Ali.

[duncan webster 1Participant @duncanwebster1]

Even cheaper, and comes with a free driver chip but no needle

https://www.ebay.co.uk/itm/195464410289?itmmeta=01HWV5PDF2Z41G443HMZN6FGW4&hash=item2d829634b1:g:QR4AAOSwkpRjx~7V&itmprp=enc%3AAQAJAAAA4N5PY8Mj1IrqW4PvFq5Mx1r464utRGx6jJ65FzO1FQh8LjSHJvHK%2FCOX53yFi6dXxV8TV%2FYlYFXF80UfxuUU32Y39ydCQ4ubTzYqo37zu7DnDlRJk%2BUHh4LYe%2FPUDvXkgcfiW3b3qRDVRoki36geP9YOmQ231Xz55ojcBsDRHtjWM7ipdLHU3SGFKovQg1NJ70rtSbbmEGKwo%2Bo%2FE0vH5B4%2FKytOW3u1o%2FUURWioLUtL7Zs7n2wxVxnz%2BgnxTBC%2FIZUOi6rUMeNpmnJAC8Ib6PRdQaKfmnSy%2BjzSxNZ6uEKg%7Ctkp%3ABFBM4tfZ5eZj

[Graham RounceParticipant @grahamrounce14492]

That’s positively elephantine! 🙂

Actually, part of my origjnal query still stands – how, purely by the pattern of activation (?) of the 2 coils, does the motor go round at all, let alone forwards and in reverse?

[Graham RounceParticipant @grahamrounce14492]

Nothing magic, I’d forgotten that each coil could be powered ÷- or -+ . It’s a standard bipolar stepper motor with a slightly unusual (to me anyway) physical configuration.

It’s explained quite well here: https://www.monolithicpower.com/bipolar-stepper-motors-part-i-control-modes , scroll down to “Stepping Modes”.  Thanks to all contributors.

[Michael GilliganParticipant @michaelgilligan61133]

Klaus is rather good at this stuff:

https://www.youtube.com/watch?v=s6Bn85Dg1HU

[one of several relevant videos]

MichaelG.

.

Edit: __ an alternative jumping-in link:

[Graham RounceParticipant @grahamrounce14492]

Good, ta

[Author]

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