micro-controller based dividing head

[EclecticNeophyte]

I realize the OP is more than 5 years old but for some reason Jon has just recycled this very interesting thread.

EN: if you are still around can you give us an update on the dividing head. Did you ever convert to the TI MSP430? And why do you consider that a better choice that the Arduino?

Hello Saltfever,

Thank you for your interest!

However, I'm afraid there's not much to report. I recall using a more robust stepper interface, as the one originally implemented burned out easily...

...later, other projects and work concerns took precedence, then in 2016 the neighborhood where I live suffered a flood. As a result of that, EVERYTHING went into storage (on higher ground), and any planned changes to my version of Chuck's electronic dividing head were put on hold. Which is where it's been ever since, I'm afraid. It's like having to suddenly pack up everything you own (that didn't get wet), as if to move.

Now that I'm officially retired, and with winter rapidly approaching, your inquiry might be the incentive I need to drag it into the light once again...

As for the MSP430 vs Arduino thing, it's really more personal preference than anything. In a previous life, the company I worked for handed me a project which required controlling a motorized 'gizmo' with valves, using the MSP430(F149). I spent the next several months developing the firmware for it, and was completely interrupt driven. Years later, when I constructed the EDH, built around the Arduino; I didn't see an easy way of implementing interrupts (I don't recall now if 'at the time' they weren't available, or I simply didn't spend enough time researching...). Polling for a button press is simply "not to be done" in my world...

A quick search prior to replying here, shows that hardware interrupts are indeed available to the Arduino developer. I seem to recall some revisions to Chuck's original code by others, so this may have already changed as well...(?) But I need to catch up. If circumstances allow, I'll do what I can to update and make any (noteworthy) updates available here...

Hope this helps,
-EN

[Saltfever]

Many thanks for updating, EN. Very sorry to hear about the flood but extremely happy for your retirement!

I been thinking about a design for a while and bought a couple of these Harbor Freight winches on sale a couple of years ago to just get the 40:1 worm and wheel. Can't remember exactly but I think they were about $23 ea. At the time I couldn't find any worm-gear set for close to that. I am not challenged by machining or mechanical fab and was going to make a purely mechanical indexing head, machining the worm gear parts to fit my needs. However, your project has encouraged me to go the stepper motor route. Unfortunately, electrical or digital implementation of anything, is a challenge for me and will take time and effort! Due to current commitments I plan to revisit this project in a couple of months.

[LeighS]

Hello, I would like to build some thing similar to your design
What torque (NM) output stepper motor did you use
Thanks

[Saltfever]

LeighS are you trying to react dynamic machining forces or do you just want to use motor resistance to hold position?

[EclecticNeophyte]

Hello, I would like to build some thing similar to your design
What torque (NM) output stepper motor did you use
Thanks

The one I used is a NEMA23, 283 oz/in. No idea what that is in metric, but I'm sure there are calculators out there that can convert...

Specs can be found here: https://www.automationtechnologiesin...t-282-oz-in-2/

Hope this helps.
-EN