[dms-discuss] CD4017 Decade Counter IC - Anyone have one?

[Bill King]

On Mon, Sep 8, 2025 at 1:46 PM l vinson via Discuss
<discuss at lists.davismakerspace.org> wrote:
...
> For your e-bike project, it seems as though the controller/display is assuming the number of poles, which is a parameter you can set on many controllers. If you know the number of poles in the motor, you can set it and have a much more accurate speed and cutoff without the need of a intermediate signal translator.
>
Logan,
Thanks for your response.

Yes, this would be the way to go if the system I'm using would allow it.

I tried to spare the list all of the gruesome details of my missteps,
wrong turns, and outright failures, but I will say this. The kits you
buy from EBikeKits <https://ebikekits.com> probably work well as a
package, but don't try to change parts unless you're brave or lucky.
They are a closed system. No wiring diagrams, no pinouts, and they
support only their packages, as is. You can ask them for help but
they'll tell you flat out. "No".

What I have is EBikeKit's proprietary version of the King Master
controller that locks out the advanced settings I need.

Hence the hack to change the speed sensor pulses by brute force.

If you want a more open approach, Grin Technologies
<https://ebikes.ca> has an enormous set of documentation and a good
forum Endless Sphere <https://endless-sphere.com> This is where I got
the suggestion to use the decade counter.

This hack could probably be done with an Arduino as well. Hell, even
ChatGPT could write it.

I'm thinking of hooking up the hub to the oscilloscope to count pulses
and see what the timing looks like. If you have any suggestions for
this or anything else on this I'd be happy to hear.

This conversion is for an underseat steering recumbent. This has been
a really interesting challenge. So far I've used the milling machine,
the metal working lathe and the 3D printer. So, why not throw in the
oscilloscope as well?

BIll

> Let me know if there is anything I can help you with on your project. I've been building and upgrading more PEVs recently.
>
> Logan Vinson
>
> On Mon, Sep 8, 2025 at 1:01 PM, Bill King via Discuss
> <discuss at lists.davismakerspace.org> wrote:
> Hi All,
> I have a project in mind and it needs a CD4017 decade counter IC.
>
> They're cheap on Amazon and elsewhere, so cheap you don't buy just one
> but 10-20. So maybe someone has a few lying around?
>
> If you've read this far and are curious, here's the project.
>
> I've just done an ebike conversion. It all works except that the hub
> sends too many speed sensor pulses so the controller thinks you're
> going 5-6X as fast as you're actually going. I don't care about the
> speedometer being accurate, but this means the speed cutoff gets
> activated way too soon.
>
> So the plan is to get a decade counter and let it see N pulses (5, 6
> whatever) before it sends a pulse as output. Returning the "speed" to
> a usable value.
>
> thanks,
> Bill
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