[artificerjon]

HELP !!

Steve has very kindly blown a couple of chips for me and now I need a pcb. I have tried the 'Press-n-Peel' film but my c****y Brother HL2030 puts two great 'cart tracks' across the print despite trying different locations on the sheet and different sheet sizes I just don't seem to be able to avoid them and I cannot get toner to transfer despite scrubbing the pcb material with scotchbright and then handling it with vinel gloves on. Is there anyone in the UK who can help me out with a pcb or transparancy of Steve's pcb design or any other so long as it works. I am only too happy to pay any costs.

[Khalid]

Marzetti,
I dont know how to make overlay so i just painted on the button with white permanent marker.
ARTIFECERJON:
Have you ever tried the normal printer paper and ironing?.. I use the office papers to lasaer print and then ironing the design on PCB. Its simple and no special paper.

[artificerjon]

Kahlid,

Thanks for the reply but I have tried the toner transfer method which didn't work for me. I have one last hope, I have found some transparency film, the stuff you used to produce OHP transparancies before Powerpoint ruled the presentation world, and have printed the layout on to it. I hope it's dense enough to let me use it to transfer the image on to sensitised pcb material via a uv light. I will let you know how I get on.

[kwackers]

@khalid.

A good way to make overlays is to print them on photo paper and then run them through a laminator. You can get excellent overlays doing this.
One trick I found was to run a sheet of paper through behind the overlay ( slightly bigger) then cut the overlay to size, doing this the back of the laminate comes away with the paper and prevents the overlay being too thick and rigid. (i.e. the overlay is only laminated on one side).

@artificerjon

I've never tried transparencies with a laser so can't vouch for them.
All my PCB's are made using inkjet printed transparencies though. However I find to be reliable I need to print them twice...
What I do is run the transparency through on 'luxury photo' mode (or whatever mode will put down the most ink), when it comes out hold it up to the light and you should see its fairly dense - but not quite black (if it is job done!).
I leave it to dry and then run it through again, that usually produces a nice dense transparency.

The problem with this method is registration. I find left to it's own devices my printer doesn't load the paper consistently. To get round this I apply light pressure to one side of the transparency as the printer pulls it in. I've had good results doing this even where very fine traces are used.

[edit]
I should add - make your transparency so it needs to be ink against the pcb rather than ink away. The thickness of the transparency is enough to create fuzzy lines otherwise...


Hope this helps.

[jhovel]

Finally, I finished my Rotary table and all is well! I machined the surface and periphery of the table itself using the indexer (in continuous mode) and milled four T-slots into it in degree mode. Very happy with it indeed!

As previously reported, the self-adhesivve cheap keypad I used had one half of the connections reversed. Since this may be an issue for others as well, I have drawn a modified version of the "Lucas" PCB which allows for both versions of keypad connections.
To confirm operation, simply wire the 4 pairs of solder pads straight through with wire links. If the keypad produces wrong numbers and commands, remove the links again and arrange them in the alternative (crossover) pattern. I suggest one pair on one side and the other on the opposite side of the PDB to make it easy to keep them separated.

Lucas: could you please incorporate that in the PDF file - I have currently no way too save as a PDF file with the correct dimensions.
Cheers,
Joe

[bronze]

Steve, Have sent you a PM regarding a similar project I'm working on.
Thanks Pete.

[Me2]

Steve,
I have completed your fantastic digital rotary table indexer. I have run all tests and all parameters work beautifully, however I have one annoying anomaly. When running in degree mode I select for example 60 degree increments and press direction, table moves 60 degrees, press forward and the table advances to 120 degrees, everything works fine until I advance to go to 240 degrees. The stepper passes the 240 degree stop and continues past 360 degrees to 1.390 degrees. If I do the same with 5 degree increments it works fine until around 220 degrees and continues on past 360 degree to 1.390 degrees.
I have changed over the chips with the same result. Has anyone else found the same anomaly? Any suggestions as to what might be causing this issue? Division mode works fine right around the 360 degrees so I'm at a loss why this occurs only in degree mode.
Edit -
I'm using the 2.11 Hex code. Power input is 12V to the board, the Gecko driver is powered separately with 36V.

Cam

[kwackers]

Hi Cam,

Just tried it on mine - and as you can guess it works fine...

Can you tell me what you've got the worm ratio set to? (or the Set Steps Per 360 - if you're using that version).

Presumably you're using a 452 and not a 4520?

Steve.

[Me2]

Thanks for the reply Steve, I have a 90-1 worm with a 200 step motor set at 1/10 stepping mode so the programed stepping ratio is 450.

Cam

[kwackers]

Hi Cam,

Basically you've exceeded the resolution of the internal maths.

It calculates a value for the number of steps per 360 of the table which in your case is 200 * 90 * 10 = 180,000.
However it's a 16 bit number so the max it can be is 65535.

The last couple of versions of the firmware require this number to be entered directly and so you can't exceed 64k.

What you need to do is change the 1/10th micro step to half step (i.e. 2 steps instead of 10). In this application there's no point in microstepping anyway.

Apologies for that, the firmware doesn't check for overflow - although I think it's mentioned in the manual....

Steve.

[Me2]

Steve thanks for the info, Unfortunately I can't change the stepping resolution on the Gecko G250 so I'll purchase a stepper of e-bay that I can adjust to half stepping. I'll let you know how I go.
I notice a few of the others are using the Gecko 10th stepper drives, they possibly haven't tried in degrees mode for a full 360 degree rotation.

Regards
Cam

[kwackers]

I'm surprised it works properly in any mode tbh.

If I had time I could probably have a whizz through the code and try to figure out what's actually going on when you exceed the limits.

Latest code though won't let you since you have to enter a value for 360 deg.

[Khalid]

Steve thanks for the info, Unfortunately I can't change the stepping resolution on the Gecko G250 so I'll purchase a stepper of e-bay that I can adjust to half stepping. I'll let you know how I go.
I notice a few of the others are using the Gecko 10th stepper drives, they possibly haven't tried in degrees mode for a full 360 degree rotation.

Regards
Cam

i also posted a video where a 144 teeth gear was machined. I am using G203V that is also 10 microstep drive but my indexer gearing ratio is less, i donot remeber but i have posted the details few pages before...

I am having no problem, i am using V2.1 firmware not the latest one.

[Me2]

G'Day Khalid, Yep mine works fine in division mode, I ran with 130 teeth as a dry run and it worked fine. However in degrees mode it ran up until around 220 degrees and it took off and continued running without stopping at the next point, I'd be interested to see if your does the same in degrees mode with the 1/10th stepper.
Steve, I'm probably going over old ground but could give the maths for calculating the ratio. I understand that the controller is set to 400 for a 90-1 gear ratio at 1/2 step ie 200 stepper x 2 = 400. At 1/10 stepping shouldn't the controller be set at 200 x 10 = 2000. I set it to 450 at it gives the correct rotation in degrees but I think I fluked it.
I'm a little bit lost, but that's usually me.

Cam

[kwackers]

The version of the firmware you're using makes an assumption that the motor is half stepping (i.e. 400 steps per rev).
This is one of the reasons I changed it to allow you to enter the steps per table revolution, it also allows oddball ratios and stepper motors to be input too.

Basically the maths works like this.

With the assumption you have a 400:1 half stepping motor then you'd simply input your worm ratio directly, i.e. 90.
But since you're 1/10 stepping (i.e 5 x as great) then you'd input that value x 5.
90 x 5 = 450.

With regards it working with bigger numbers, I have a theory but without working it out in the code I can't be sure...
In simple terms though I think the overwrap isn't an issue as long as the values are small enough. (I can't test it here because the later version of the software won't allow me to input a big enough number!).

[jhovel]

Kwackers and Me2:
I'm using the G251 (1/10th step) driver too. My worm ratio is only 30:1 though, that's why mine works fine too.
What you say makes perfect sense, Steve - I'm glad I accidentally used this small ratio worm drive!

[Khalid]

Me2,
The same happen to me when i was using cheap chinese keypad..it was very sensitive, also i was using the PCB by the STEVE at that time..may be some problem,... After few days my whole PCB and the PIC IC found damaged, so i did the new PCB with thick routing someone posted 3 or 4 pages before..I also made my own version of keypad and now i have no problems at all..
I will check by tomorrow whether in degree mode i also get the problem like you.

[Me2]

Thanks for the input and help felle's, Payday next week so I'll buy one of these -

Cnc 3.5A 2 phase hybrid stepper motor driver controller | eBay

Should do the job nicely. My input power supply is 36V.

Cam

[Me2]

G'day Steve,
Received my half stepper driver today. Hooked it up and everything working perfectly. Very happy! I've printed off a few keypad overlays, they are the one side laminate as previously described. What have you or others done to 'glue' them down to the face of the keypad, I was looking at a non wetting adhesive like silicon so the print doesn't bleed from underneath when in contact with the adhesive. Any other alternatives?
I'll post pics when I get the whole thing into a box and setup.

Thanks again

Cam

[Me2]

G'day Steve,
Received my half stepper driver today. Hooked it up and everything working perfectly. Very happy! I've printed off a few keypad overlays, they are the one side laminate as previously described. What have you or others done to 'glue' them down to the face of the keypad, I was looking at a non wetting adhesive like silicon so the print doesn't bleed from underneath when in contact with the adhesive. Any other alternatives?
I'll post pics when I get the whole thing into a box and setup.

Thanks again

Cam