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I made a custom "friction-less" jog wheel for working on long documents

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evglabs:
I've been getting into teaching myself STM32s and made a jog wheel.

It uses an STM32F042C6T6 to read a small DC motor connected to a differential opamp and works as the scroll wheel of a standard USB mouse.

The case measures 44mm diameter by about 50mm tall.

I now it's not as fancy as a lot of the other projects I've seen here but I'm proud of it!

Video in action:
--- End quote ---

Yansi:
Great, but this is already long made and supported on many computer mice. Just a click to switch between cogged and freespinning mouse wheel.

Also, you shall learn how to split source code into files.  ;) ;D

//EDIT: Also, to stay on topic. Adding an ESD protection device on the USB would not hurt.  USBLC6-2SC6, to name one.

Also, having just only a small ceramic cap on the power supply input without overvoltage protection or additional dampening is asking for trouble.

Add via stitching to your ground plane!

Why does the NRST pin appear to not be decoupled to ground with a 100n cap, rather to some other trace common with likely BOOT0 pin?  Where is the BOOT0 pull-up resistor? This pin is HiZ, there is NO integrated pull-up.

And lastly a design note: Why a DC motor as the encoder? You need a POSITION encoder, not velocity one.

evglabs:

--- Quote from: Yansi on December 08, 2019, 07:03:27 pm ---Great, but this is already long made and supported on many computer mice. Just a click to switch between cogged and freespinning mouse wheel.

--- End quote ---


Yeah, I have a Logitech (a few actually) with that, but every Logitech mouse I've had I have to replace the left button a couple of times. So, I figured it'd be a good learning project and give me the functionality of it without being dependent on the mice.

Plus it's nice when reading a datasheet of reference manual to be able to use my whole hand to scroll instead of my finger.


--- Quote ---Also, you shall learn how to split source code into files.  ;) ;D

--- End quote ---

Never!  ;) Give me one monolithic file or give me death!

evglabs:

--- Quote ---Also, having just only a small ceramic cap on the power supply input without overvoltage protection or additional dampening is asking for trouble.

Add via stitching to your ground plane!

--- End quote ---

I'm still learning, and half the time (all the time) I don't know any better. Right now, it's if it works, it works. Any problems are for future me to deal with. Screw that guy.


--- Quote ---Why does the NRST pin appear to not be decoupled to ground with a 100n cap, rather to some other trace common with likely BOOT0 pin?  Where is the BOOT0 pull-up resistor? This pin is HiZ, there is NO integrated pull-up.

--- End quote ---
The NRST is actually decoupled to ground with a 100n cap. The BOOT0 pin has a jumper to connect to ground (and the two share the same ground connection).


--- Quote ---And lastly a design note: Why a DC motor as the encoder? You need a POSITION encoder, not velocity one.

--- End quote ---
The DC motor is cheap (a salvage from a DVD drive) and really, I don't care what the position of the encoder is. Just the direction it's moving. 1/2 VDD no movement. < 1/2 VDD = scrolling down (and lower voltage equals to scrolling down faster) and vise versa for scrolling up.

t1d:
Bravo, evglabs, for wanting to learn by doing! This is a great project and comes from the heart of DIY-ing. I am sure you learned a large amount and that was the point of it all. I salute your efforts. Keep at it. Please keep posting, so we all can learn together... mistakes included.

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