Gemmasta Encoder Mod Thread

[MakkyBrown]

I thought I'd start a thread to keep this in one place as hopefully others will do this and we can share ideas to improve our machines.
As a new owner of Tom Herbst' faceting books the first thing I did was turn to the digital encoder build pages and had already purchased a lot of parts before the books arrived I was that keen. http://www.facetingbook.com/books.html
I put a lot of thought into which encoders I could mount on the machine and I was initially going to mount the encoder in front of the large brass nut on a raised mount. This wasn't ideal and would have resulted in the wires moving as you lifted the hand piece up and down. I had been in email communication with Rusted who suggested putting a small shaft through the centre of the shaft the large brass nut goes onto. This was something I hadn't thought of and a great idea , so rather than drilling the current shaft and potentially wrecking it, I turned up a new shaft with a 2.7mm hole through the centre of it and a fine thread on the side the dome nut goes onto. I've fitted it all without drilling any holes into the machine so it could easily be converted back to it's original specs.
The movement is transferred to the encoder wheel down a 2.5mm shaft. Luckily(to my amazement  ) my new shaft I turn up is pretty much perfectly true so the movement can be transfered back down the smaller internal shaft without any flex or need of a pivot. The large brass block the encoder mounts onto replaces the nut and is half threaded/ half 2.5mm brass bearing, and honey comb drilled to reduce weight.
I have modified Tom's code/files a little bit to suit my build. Happy to help anyone else that's purchased Tom's books and is wanting to have a go BUT I'm not a good enough machinist to make new shafts for other gemmasta's. The screen looks a lot better/brighter than in the photos. I also had to replace the angle adjuster knob with a lever, turns out it's really nice to use, far more ergonomic.
Hope someone finds this useful.
Cheers
Andrew

[Orange Pirate]

That is absolutely brilliant. Awesome.
What encoder did you end up using?

I hope one day to get some thing happening on mine using a PICxx. RPM was another feature that I thought may be handy. But that is great.

Cheers
OP

[Bucket]

Great work Andrew, it looks terrific. Have you tried it out yet?

[MakkyBrown]

Great work Andrew, it looks terrific. Have you tried it out yet?

Sure have Bucket , I've cut 3 stones so far with it , angle encoder is spot on and has basically no error. Though hasn't got the resolution to cut with by itself imo. The depth of cut indicator(separate circuit) has taken a bit of sorting but I'm getting used to it. Today I cut a set of mains using just the indicator without checking as I went and they were perfectly even. The program also stores angles used on screen two, you reference back to them, then dial them in etc quickly.

That is absolutely brilliant. Awesome.
What encoder did you end up using?

I hope one day to get some thing happening on mine using a PICxx. RPM was another feature that I thought may be handy. But that is great.

Cheers
OP

The encoder is a US Digital E2 encoder, 1250cpr,5000ppr gives me 0.072 degree steps. The encoder also has an index so the unit recalibrate every time the hand piece is lift above roughly 95degrees. I got it for about $50 of ebay, I'd like a 5000cpr encoder but they are a  expensive with the weak AU$$ and imo not sure if there would be any real advantage in getting one over the one I have. Maybe one day as it would be easy to change.
Might have to look into rpm I could display it where the unneeded title is on the screen.

Cheers
Andrew

[Rusted]

Thats a great job Andrew.
Glad you got the interference problem sorted.

I have several different screens coming, I ordered a 16 character by 2 line board and then realised it probably wasn't big enough so ordered the right one and then found a full colour touch screen so ordered one of those too, so there should be plenty of room to put RPM. Room temperature, Real time clock, minutes to lunch time, days to my birthday, endless possibilities, just to show off.
Knock off Chinese Arduino boards and shields are really really cheap.
I am still waiting on my encoder, pacing back and forth like a caged lion.

Paul

[Aussie Sapphire]

Good work.


If anyone wants to do (or collaborate on) an instructions document for this, happy to put it up in the downloads section.


There are lots of old gemmastas out there that could benefit from a tech upgrade.


cheers
Leah

[MakkyBrown]

Rusted,
I find every time I send an email about where is my parcel it will turn up the next morning.   
One thing I did buy locally was the alloy enclosure from Jaycar, it was hard to find a cheap one on ebay. It was a perfect snug fit for all the bits.
http://www.jaycar.com.au/Enclosures-%26-Panel-Hardware/Metal-Boxes/Diecast/Economy-Die-cast-Aluminum-Boxes---119-x-93-5-x-56-5mm/p/HB5064
Webpage says out of stock but my local store had heaps. The screen and Uno are mounted(screwed) to plastic feet I glued to the alloy. The Uno is mounted to the lid making it easy to access which is handy as I have to disconnect the +ve and gnd for lcd before the Uno will let me upload code.
Cheers
Andrew

[MakkyBrown]

Leah,
I should have taken some more pics before it all got calibrated. Not quite sure how to go about an instruction set as it will be variable how each individual would build this. I'd also like to get an ok from Tom Herbst as I feel anyone building this should atleast buy his books as a thankyou for the idea and base code. Technology, arduino support codes, wiring all change very quickly. I found I had to make a good few changes to get it all working. More than happy to help others building this with what knowledge I have(code, components, wiring I used etc), but step by step instructions could be a bit tricky. Maybe(not sure what's possible) a members folder location to put build pictures, arduino code, useful links, parts lists etc could be handy as this thread could become lengthy.
Cheers
Andrew

[Aussie Sapphire]

More than happy to help others building this with what knowledge I have(code, components, wiring I used etc), but step by step instructions could be a bit tricky. Maybe(not sure what's possible) a members folder location to put build pictures, arduino code, useful links, parts lists etc could be handy as this thread could become lengthy.
Cheers
Andrew

No problems to keep all in one long thread - doesnt really matter too much if there are a few pages to scroll through.  Might be an idea to keep any related pictures in one single gallery album though if there turns out to be more than a few.  I can create one if you want me to.

cheers
Leah

[Rusted]

My encoder just arrived, Yahoo.
Its wired already with screened cable so I might be able to eliminate all the mucking around with screening and ferrite slugs.
As I have almost the full build to do apart from the shaft I will take lots of pictures so together we might be able to get an instruction sheet up.
My encoder is quite a bit deeper than yours and has a shaft sticking out about 12mm so the mounting is going to be different and I dare say a bit messier than yours, certainly a bit of thinking to do. I am going to need one of those lever type knobs too.

I was going to contact Tom Herbst myself to ask permission to use his Gem101 diagram at the club but I couldn't see a way of contacting him. I know he is sometimes on the gemology forum so we might need to go via that forum.
Paul

[MakkyBrown]

I'll pm you his email.

[Orange Pirate]

a US Digital E2 encoder, 1250cpr,5000ppr gives me 0.072 degree steps. The encoder also has an index so the unit recalibrate every time the hand piece is lift above roughly 95degrees. I got it for about $50 of ebay,

Thanks for that. You've certainly got the old brain box thinking.

An instructions thread would be a great idea. Tips, photo's, tutorials, code, etc..

Cheers
OP

[daw1zard]

what an awesome upgrade to the Gemmasta. i would love to see some photos of the angle adjuster lever, i don't have this feature at all on my machine.

Troy

[MakkyBrown]

a US Digital E2 encoder, 1250cpr,5000ppr gives me 0.072 degree steps. The encoder also has an index so the unit recalibrate every time the hand piece is lift above roughly 95degrees. I got it for about $50 of ebay,

Thanks for that. You've certainly got the old brain box thinking.

An instructions thread would be a great idea. Tips, photo's, tutorials, code, etc..

Cheers
OP

I'd love a 5000cpr, 20000ppr encoder 0.018degree steps  one day, easy to swap over.  I might start putting some info into a word document over the next week or so.

[MakkyBrown]

Hi daw1zard,

The lever is similar to these, M8 thread  http://www.ebay.com.au/itm/281732028352?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I had one lying around and needed a solution to the encoder/mount being in the way of the knob. I drilled a hole down the centre of an M8 bolt and tapped it to 3/16 whitworth from memory. Loctited it into the lever and cut off flush.  Removed the spring that went into the existing knob. Was surprised how nice it is to use and am tempted to change the knob to an adjustable lever on the mast clamp.