I used microswitches and relay for end of travel and stop switches on my mill table drive. Seemed better to rely on hardware for something that has got to work or it gets expensive. Arduino takes care of speed and ramps. Might not be applicable to your situation but send me a pm if interested

Hi Daggers,

It is not to complex to add switches to your setup. If you can do some basic software programming, then it can be done quite neatly. If not, you could achieve the same end with some micro switches and what I term a 'bypass'

Fit microswitches at each end, series the normally closed contacts of both , and feed the stepper pulse through these contacts to the stepper driver. When the uswitch is activated, the contact opens and the pulses no longer reach the stepper driver, so the stepper halts. Then you need to fit a momentary ( push-to-make) switch across both microswitch contacts, so that when you press it, it allows the stepper pulses through again, so that you can back the axis off of the activated microswitch. Once the microswitch is no longer activated you release said push-button and carry on with normal operation.

Doing it in the software would alleviate the need for the pushbutton, and you would then just connect the microswitch contacts to a processor input port and when the software sees the contact activate, it stops generating stepper pulses, basically halts the axis 'feed'. Then the software would disallow further auto-feed motion, till the axis is backed of the switch position, and the switch contact becomes inactive again.

If you are not comfortable mucking with the software, the 'manual' switch method is easy to implement; alternatively, I am sure there are other Aurduino aficionado's who may know the MEW project and could assist with some software.

For general interest, these days it is almost not worth mucking about with hall effect sensor and magnets and how to mount the bits, and protect the sensor from swarf, etc – there are many inductive proximity sensors available so inexpensively, all sealed, easy to use, etc – here is an example, and at $3.19, with maybe even free shipping in the UK, it cannot be beat..

**LINK**

Joe

Without being presumptuous, I took Daggers statement ' I am not an electronics expert so i am not sure how to achieve this, if it is possible.' to mean that possibly he is also not a software fundi…

And anyway, counting the pulses does not work either, as you have no zero reference – the stepper positions in this application are not absolute, so you would first have to move the axis to one end, and set this as a zero reference and count from there, or use an axis centre reference and count plus/minus from there – and you would need a reference switch of sorts to know you are at the reference point.. either way, it is a pain to first reference the table each time you turn on the machine – normal in the CNC world, but not in a manual machine situation.

Joe

I think the simplest solution would be to wire two stop microswitches in series and use them in series across a break in the wire I have indicated in the handset.

Although this means at least one more wire in the handset cable, this will stop the travel in 'run' mode but allow you to inch the feed (in either direction).

Alternatively just break the pulse wire inside the unit, but then you will need to manually move the feed back from the stops.

A better but more complex solution would interact with the direction switching so you could reverse out. One way would a relay operated by the direction wire to choose between two microswitches so the stop only works in the appropriate direction.

Neil