S3 Spindle Control, final redux

I’ve just finished adding automated router on/off control to my S3XXL. It’s working like a dream and I documented the entire process, end to end in the wiki here:


Thanks to @WillAdams and @RichCournoyer for their advice and input, and thanks to everybody else who contributed to the community, which I drew on.

If you’ve got ANY questions or suggestions, please post them!




Nice one, am I correct in thinking you have used Ground PWM to trigger a relay to turn the spindle on/off. Then there is a manual cut off/switch?

You got it. There is an interrupter switch between the relay and the router (or the relay and the power, if you prefer.

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Sweet! I’ve been thinking of doing this. So Grd & PWM are the same as pins 3/6?

Which pin was speed for water cooled spindles?

if you’ve got a board with the four pins at the top (2.4d and later, I think), then yes, those pins are the same. The PWM pin puts out a Pulse-Width Modulation. An oscillating signal whose length is proportional to the speed (0-10000) that is passed. We’re just cheating the fact that at 100% duty cycle (or 10,000) the PWM signal looks enough like a solid +5VDC that the relay believes it and trips.

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how is this running with your sender and tool change?


This site states there are other pins you can hook up to?

So if using a VFD, do you require an on/off as above of is that the same as PWM

Looking at doing this tonight. Currently I want to hook it up to a standard dewalt, but in a few months planning an upgrade for a VFD. I want to ensure I only mess with the board once.

It will depend what the VFD is looking for as input. Most will take PWM as speed and power signal. If you pass an M5 the pin goes completely dark. Most good Variable Frequency Drives can be configured to scale a certain PWM range as speed. YMMV, I’d check out the documentation on the VFD.

Sounds good, any idea about those other pins in the Previous post?

Went and bought a plug socket today to wire this up this evening.

Take a look at this thread over at the Shapeoko website. A few years ago, a couple of members and I did some investigations into the early Carbide Motion boards, and I expect that they would be the same today. Be sure to read through the whole post, as there is some key info on the second page as well.

I believe the latest version of the Carbide Motion controller routes these pins to the upper right edge of the board, marked with PWM, D13, and GND. You should be able to wire up to those, and not have to fiddle with the ISP header.

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Wonderful thank you, I have actually gone ahead and soldiered on pins to the edge of the board and they appear to be working. When I click spindle on I can get external LED to turn on - so PWM and ground are a go.

I’m waiting on a new relay (expected tomorrow), which will allow me to turn the spindle on. I will take a slightly different approach and build it into a socket - that way I don’t have to pull appart the router.


@Luke despite the diagram I gave, that’s how I have mine wired: The switch and relay power an electrical outlet, into which the router plugs. Good call!



So I completed my installation today - as I only had automotive relays I opted to copy you and purchased the same relay (identical available in the UK on amazon).

The instillation was flawless however I note some different results. I mounted my relay outside of my S3 enclosure as not to have high power cables running through the box or more heat in it. I mounted it to my wall. After 1 hour + of milling it wasn’t even warm - I’m not sure why it would have been hot in your tests?

Based on this I might look to build it into an electronics enclosure…

Also there is a strange ‘feature’ in CM - when you click start - the spindle starts then it asks you to insert tool? somewhat silly? It might be my code - what results are you having?

P.s. thanks this is super cool - I’m slowly feeling like I have a large Nomad :smiley:

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The tool insertion dialog is there to allow one to do tool changes on a Nomad and then measure the tool — not sure how the logic could be worked out to make it safe enough for both machines w/o having it there.

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Interesting - that said I won’t be trying to change my tool with it on.

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Let me ask differently, have you run your spindle control using CM4 in a multi-tool job? If so, has the spindle control worked correctly (off during tool prompt)?

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Not yet, I only ran one job today to see how it functions in the most basic way.

Thanks, would like to know how this works

yes it does.With a spindle, you can control the speed also!

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