Probe Interface Board Design (resistance switching)

After a bit of a delay (for reasons), I'm now back to testing the populated board on my machine rather than the bench. Although I've yet to do the micrometer test, it appears to work - it is, as expected, quite sensitive to electrical noise. For me, this only occurs when turning off the mist relay but as I found out over the weekend, this will stop a running job!

I may be able to tune is out but I'd also like to disable the probe input in hal when the probe tool is not inserted (to also prevent the spindle from being turned on) - I've not yet found out how to do this, so will likely create a separate forum thread...

Edit: Scratch that. Solved with a big ol' flyback diode across the solenoid contacts (which I thought it already had on the tiny PCB next to the contacts)...

If anyone would like a v1 PCB, I'd be happy to send you one for the cost of the postage.

Prolly easier to just dump schematic & bom. Bet a few here could improve it where it needs and if it needs. Happy to assemble one myself and give it a trial, got 6 weeks off starting mid-may~end-june...

Mecanix wrote:

Prolly easier to just dump schematic & bom. Bet a few here could improve it where it needs and if it needs.
Happy to assemble one myself and give it a trial, got 6 weeks off starting mid-may~end-june...

 

S'funny you should suggest that cos I've just pushed the schematic and BOM to github:

github.com/Stutchbury/CNCProbeInterface/tree/main/docs

I think "if it needs" might be a bit optimistic   It works well so far but I completely forgot about an 'enable' option and there may be better ways to do certain things.

Not sure PMs work here but my email address is on my github page.
 

I've also just uploaded the case and din rail mount (my first print-in-place design).



github.com/Stutchbury/CNCProbeInterface/tree/main/stl

Enjoy

Oh christ who came up with this springy pcb clippy idea? that's just so brilliant (and useful)!!!

Placing the monthly passives and components order this coming week. I'll swing in what's needed in that lot. Nice work man

Mecanix wrote:

Oh christ who came up with this springy pcb clippy idea? that's just so brilliant (and useful)!!!

Placing the monthly passives and components order this coming week. I'll swing in what's needed in that lot. Nice work man
 

Thank you - the design is mine but based on something I saw a year ago with a single 'spring' but now, of course, can't find - so I can't take all the credit.

Quick update: I did some more testing today with my new improved Renishaw mount, complete with magnetic connector:
 
and am very happy with the results:
 

My test 'hole' is exactly 20mm (I always thought they were never exact, but this one is bang on the money) so to be between just 8-35 thousandths of a millimetre off makes all the effort worthwhile. Repeatability of less than a few thousandths is good too.

I'm sure if I wasn't using a 21 year old probe it would be even better but the ability to 'tune' the resistance of the knackered contacts was very useful.