Quote:
Originally Posted by EddyCurrent
That works on so many levels, a complete solution, I am truly in awe :beer:
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Quote:
Originally Posted by EddyCurrent
That works on so many levels, a complete solution, I am truly in awe :beer:
Almost, but not quite. It just needs a solenoid-operated lever to give the user a slap on the wrist when the limit switch is triggered.Quote:
Originally Posted by Robin Hewitt
Like me you are forgetting Gotama's advice to Siddhartha... "Beware of too much cleverness".Quote:
Originally Posted by Neale
When I was about 20 years old my work colleagues presented me with the (fictitious) Duke of Edinburgh Award for 'Use of Stone Age Tools'.
Or, when the handle stops turning, you've hit the end stops.Quote:
Originally Posted by Neale
OK, here's version 0.1 for discussion....
Attachment 12250
As touched upon earlier, the 'jitter' this adds to the pulse stream will reduce the maximum feedrate somewhat as the motors wont run as smoothly. How much is hard to say, but it could be a problem...Quote:
Originally Posted by irving2008
Direction required?Quote:
Originally Posted by irving2008
More and more it looks to me that the best approach is a mechanical step-up! Trying to multiply the number of pulses electronically is inherently the wrong way to go.
Fix the mpg down on a board and mount a larger mdf wheel next to it on an improvised pivot. Use a wide rubber band as a belt . Should be relatively easy to get a 5:1 step up.
Better still, connect the rubber band to the stepper motor to get a closed loop system. I'm sure you'd get positive feedback for that idea ;)Quote:
Originally Posted by JohnHaine
Jonathan I'm even surprised you botherd to comment so I thank you for that.!! . . . . . As for your input then I expected no less from you.!!Quote:
Originally Posted by Jonathan
Sorry to the rest for not replying sooner or keeping track of this but I've been busy all weekend wrestling unfriendly CNC machines.!!
Ok well let me explain again that ALL i want to do is have the axis move, doesn't matter if it misses steps or stops fast etc just move faster than 1 pulse at a time so I can get from one end of machine to other with cranking the handle 1000's a time.
All I wanting is like Irving says to move the axis while working on machines and for setting up limts switches etc. This is why I would like to have the single pulse detent for when close to limits etc. Before that it won't matter if it gets infront or behind with pulses etc and overruns or misses steps etc as I'm not after any accuracy and when I'm getting close to where want to be I'll drop to single pulse. Sure when used to it I'll know how it's going to react to my turning the handle at differant speeds.?
To those that have suggested mechanical options then YES I know this and I can even push bloody the axis if I wanted but that's not what I want so please don't go there anymore it will only take the thread off at tangents.!
Similar with the arduino and software based options, yes I know they are best or easier option and yes I've done some VB and C++ coding so could after cleaning the rust off gone this route and made it happen.!! . . . But again didn't want to. Just want it rough arse KISS approach and to learn from.
555 timer hasn't been ruled out but I would have to have the single step option like the detent of the MPG.
I'm flat out busy at minute but when I have more time I'll look closer at it and ask some folks I know that have done similair things.
But in mean time please keep giving the suggestions but just remember only needs to be simple doesn't need any thing fancy I'm not after accuracy or any kind of CNC pendant.!!
CHEERS:
Added option to replace DIP switch with rotary for presetting step multiplier rate.
Attachment 12259
Given the above refined spec with direct ratio not required, rather than a pulse multiplier I'd suggest a frequency generator with the output frequency programmed to ramp up and down quickly but smoothly with the running target frequency output based on the pulse frequency input.
I'm afraid I don't have my PIC programming system set up at the moment, it's all in a box somewhere in the loft :-(
If only I had an Australian Bloke's Shed, then I could have all my toys out at once!
- Nick
A possible issue with the mechanical option is potentially the pulse rate the wheel can achieve. One datasheet shows one such wheel has a fixed 800uS pulse per detent, which limits it to 125 steps/sec or 75rpm.
This does not directly answer Dean's request but . . .
If I was building cnc machines I would have as a minimum a box with a bob, power supply, 2 x stepper drivers, vfd, all wiring to a bank of terminals to allow easy connection of limits etc.
This would be connected to a PC with a parallel port running Mach3, there would be two sockets mounted on the outside of the box so that by using a flying lead, individual stepper motors could be connected or if the machine used two steppers on X this could also be accomodated.
This system would allow use of a remote pendant or you could use the Mach3 interface to directly enter G0 codes for moving the axes around, the bob would allow connection of limits and home switches for test purposes.
I believe this would cover all the requirements specified by Dean in the most productive and hassle free manner and from what I've read he probably has all the required parts already, unless of course he has some other, not yet revealed, idea for using the minimalistic approach.
How about a hybrid system, keep the MPG for fine control but have a button that also injects pulses from a (variable frequency) 555 timer type circuit? Direction is set by the wheel and that is used for fine adjustments but for rapid traverse, the button is used.Quote:
Originally Posted by JAZZCNC
Bingo. :applouse: ..CliveQuote:
Originally Posted by FatFreddie
Yes I do this already eddy, I have a test rig setup with BOB, SS and 4 drives VFD etc so can test a machine is fully working while on the bench but some times I need to move an axis SINGLE axis away from the bench or before all wiring is done IE short stepper wires so I want simple portable unit to do this. Also some times I have more than one machine on the go and at differant stages of build so Don't want to have to lug PC and all the stuff to machine if it's not on the main bench.Quote:
Originally Posted by EddyCurrent
Attachment 12260How about a USB games controller like this. Mine cost me nowt, uses keygrabber and the biggest hassle was putting the labels on the keys.Quote:
Originally Posted by JAZZCNC
Nope.!! . . . . Remember NO PC involved.Quote:
Originally Posted by cropwell
Yes this is an option and will be my backup if nothing full fulls my perfect needs.Quote:
Originally Posted by FatFreddie
Irving I'm following your design and with some googling I've found it uses a Hex Schmitt trigger, Flip flop and down counter so I'm learning already . .:yahoo: . . . . Now I just need to get my head around what they are and how they play together.
While googling the codes have been showing up with letters on the ends like "BE" or "BCM" what do they indicate.?
Should I start to play with this now and get these bits to play with or will there be more versions so hold off.?
Hi Dean,
You wanted a learning experience so I deliberately left some info off the diagram. :)
These chips come in various package formats, the suffix identifies which so decide how you're going to build it and get the appropriate version. If you're breadboard it you need the PDIP package.
I don't foresee any major changes and these chips are only 30p or so so get them. Maybe even a couple of each just in case :)
I do need to consider Jonathan's valid suggestion re direction so there will be a v0.2 shortly.
Yes I'd considered this approach but rejected it as too easy lol, also doesn't truly meet Dean's original criteria.:)Quote:
Originally Posted by FatFreddie
Here's another idea.
I used to work on plant where Selsyn Motors were used for synchronisation purposes and remote indication. It occurred to me that stepper motors were very similar so a quick search found this;
Fun with Stepper Motors - Synchronous Operation without Power - YouTube
No external electrical power required just a crank handle on a spare stepper motor.
Ye played with this before and while it will turn another motor on the bench there's no torque obvioulsy due to low current/volts.Quote:
Originally Posted by EddyCurrent
Good man I like a challenge. . LolQuote:
Originally Posted by irving2008
Yes BB at first then will probably make a better job with a board.Quote:
Originally Posted by irving2008
Ok there's no rush so I'll wait until everything settles down then just buy a load of bits at same time and I'm sure there'll be plenty of Magic smoke in the air so I'll get spares. . LolQuote:
Originally Posted by irving2008
Not being savy with these electronictrickery gismo's then it's probably technical chip stuff why it's a problem but Won't the drive take care of the Direction just with 5V on the Dir pin.?
Post #48-49: Looks like that was meant as a serious comment - sorry I didn't realise.
If you apply 5V across the DIR pins the motor will spin one way, apply 0V (or leave disconnected) and it will spin the other way. You could could do that simply with a switch if you're happy for the machine to go in the direction set by the switch, not follow the direction in which the MPG is spun.Quote:
Originally Posted by JAZZCNC
Obviously I know this and thats what I've been doing just with MPG. This is what I've been saying I just want it simple so flicking switch is fine and spinning mpg just for movement. Just I need faster than the single pulse the MPG spins at but still want the abilty to single step when needed.Quote:
Originally Posted by Jonathan
555 + MPG would work and would probably be simplist but I don't mind playing and want to learn something in the process and so long as Irving or some other kind sole doesn't mind giving directions then I'll wait and see all the options.!
if you're ok with a switch for Dir then there won't be a v2 at the mo.
Suggest, if not done already, you download & print off datasheets for chips and get a handle on what each does.
Yes that's fine Irving and yes data sheets already downloaded but not looked at yet.Quote:
Originally Posted by irving2008
I was thinking about the pulse generator part of the circuit. What about having a small microphone feeding into a high gain op amp with a couple of reverse connected diodes from the output to ground, then another stage to bring it up to 5v.
If you whistled into the mic then the output from the op amp would be a square wave, we used to make guitar fuzz boxes like this yeas ago.
Now combined with a direction switch all you would need to do was whistle a note that was proportional to the required speed.
If I weren't bothered by the current limitation I would use a Parker Digiplan PK3, ('cos I have one sitting in a cupboard) 2 buttons and a switch and you have 3 speed travel in both directions. I have also got 3 PK2's in the same dusty cupboard.
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I have been sparked with the idea of building a test rig with a couple of proximity sensors and dial gauges, just to see how fast you can accurately move the axis repeatedly back and fore, using the drivers intended for the final build. For that I would use an arduino to give a fixed number of steps with different rates and accelerations.
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I am retired though, so I haven't got the impetus to get up off my fat arse and do anything :indecisiveness:
How about the impetus being lifes to short even at advanced age so get your fat lazy arse up and live life before the lights go out.!! . . . . If that don't do it then how about just for the sense of achievement and warm fuzzy feeling it gives.:bee:Quote:
Originally Posted by cropwell
Good grief ! you don't arf sound like the missus.Quote:
Originally Posted by JAZZCNC
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I spent the morning on hold with BT while they tried to assert there was no network fault. I have to go back to Stuart Akroyd Glass when they have broadband, to set up an IP camera to monitor their furnace control panel.
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I spent my afternoon in the workshop making a header tank stand.
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It's 00:30 and I have just got back from the workshop, setting up a coolant system for my new lathe. Minor problems yet to solve but it is nearly another project ticked off the list.
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As my arthritis progresses, my mobility restrictions frustrate me as I can't do what I want to do at the pace that I want to do it.
YES I am fat, but you put in the word lazy, not me.
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Actually Dean, I was more expecting to have my idea about the Digiplan blasted.
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:highly_amused::highly_amused:
Wasn't really having ago or blasting at you mostly was bit of fun with slight meaningfullness.!! . . . . I'm probably a little touchy regards not living or folks whinging or whining about what are in the grand scheme of life nothing problems as I've got loved ones living on borrowed time with the Big C, lost familiy and 3 close friends in 3yrs to this Evil disease. . . . So if I was curt then I'm sorry didn't mean to be.!! . . . . . But the message is the Same GET OFF YOUR ARSE before it's too late.!!Quote:
Originally Posted by cropwell
The word Lazy was implied by your definition "get up Off my fat arse" doing nothing "Sloth" is lazyness.!! . . . ("Fuck" I'm sounding like Jonathan now so I'll stop)
Nah THEN. . Back to this Digiplan Crap. . Lol . . . . Nah I'll leave this one here. . :thumsup:
The easiest solution I can think of is a higher count encoder.