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JFettig
03-10-2005, 04:29 PM
I was about to start building an mpg, then I realized I have a problem with switching directions, I was gonna take a 1.5" aluminum cylinder and make 50 dents in the side which would make contact with a switch, Although I then dont have direction, only step.

I have seen one with the same concept, and saw him using 2 switches I wasnt sure how it worked and all, I am pretty sure it was on here but for the life of me cannot find it.
I looked into encoders, too expencive.

Whats next? I think it might be possible to hook up 2 of these switches in such a way that they send the signal one way or another, again thats still quite difficult and hard to figure out.

-edit- MPG is a manual pulse generator, for controlling a cnc with a wheel like the big name cncs have.

Let me know if you know anything.

Jon

miljnor
03-10-2005, 06:21 PM
personally and encoder is probably the way to go. but if your looking to make it. Your Idea sounds feasable. just make two detent wheels for the same knob and make one only turn one direction and the other turn in the other direction, with two switches.

there are clutch bearings already on the market that do this. don't know the part numbers but if you cant find them locally let me know and I can ask my bearing house.

Michael. t.

JFettig
03-10-2005, 06:28 PM
That was another idea, I just wasnt sure how to make it do that. I havent heard of clutch bearings but Ill do a search.

Thanks,
Jon

ger21
03-10-2005, 06:47 PM
You can set different increments for each encoder count. And you can cycle through these different settings with alt-J. I would think you could use keygrabber, and use a button to cycle through the increment settings, then the low encoder counts wouldn't be that much of an issue.

gmfoster
03-10-2005, 06:53 PM
I was about to start building an mpg, then I realized I have a problem with switching directions, I was gonna take a 1.5" aluminum cylinder and make 50 dents in the side which would make contact with a switch, Although I then dont have direction, only step.

I have seen one with the same concept, and saw him using 2 switches I wasnt sure how it worked and all, I am pretty sure it was on here but for the life of me cannot find it.
I looked into encoders, too expencive.

Whats next? I think it might be possible to hook up 2 of these switches in such a way that they send the signal one way or another, again thats still quite difficult and hard to figure out.

-edit- MPG is a manual pulse generator, for controlling a cnc with a wheel like the big name cncs have.

Let me know if you know anything.

Jon


It seems as if you would mount two switches such that one is on a ridge when one is in the valley you could get what is needed to act like an encoder. The switches could even be on nearly opposite sides of the wheel.

Garry

JFettig
03-10-2005, 07:00 PM
I was thinking that too, both for higher resolution and thinking about how I could get it to give me direction.

Jon

miljnor
03-10-2005, 08:02 PM
Just though of something I read in another post (cant remember which one) but you can get realy cheap encoders from and old ball style mouse. don't know the wire outputs but I am sure someone here does.. just a thought... when I get to that stage, this will probably be my solution.

Michael. t.

JFettig
04-12-2005, 01:00 PM
I got a couple shaft encoders, one 4000 ppr(1000cpr?) and 2 100cpr encoders. I only have the 1000cpr encoder at hand, and i have it hooked upto mach3 but when I jog with it, it only jogs slowly and by .001"

Does anyone know how to make it jog as fast as I turn it and all? its quite annoying to have to jog a distance but not being able to go fast.
I have messed with feedrates, and anythign else I can think of, the velocity doesnt change anything in the settings.

Jon

turmite
04-12-2005, 01:14 PM
JFettig,

Take a look at this screen shot. You can set the jog amount as well as continous or single step. Sounds like you have it set to move .001 per step.

Mike

JFettig
04-12-2005, 01:15 PM
Yes, you are correct, I see that now, but it moves incredebly slowly. I would like to have it move where I tell it as fast as I tell it

-edit- I am running this in mach3 lathe, the switch axis thing doesnt seem to work either.

Jon

JFettig
04-12-2005, 01:22 PM
I got it, I had to turn on MPG velocity
found the jog screen in mach3

Thanks,
Jon

ger21
04-12-2005, 01:39 PM
Jon, there is talk on the Yahoo group about a group purchase of encoders for MPG use to get a better price, you might want to look into it if you need any more.

JFettig
04-12-2005, 01:46 PM
I have 1 in my posession, another 2 comming within the next couple days, I got about $40 into all 3 of these, the 2 come with handles too.

I will probably make handles with dents so it clicks 100 times per revolution.
I think I got all the encoders I need now:)

Jon