Need Help!- Home switch solutions for 8020 based machines...

[Arbo]

Just curious what those folks who have an 8020 based machine have done for home switches, mostly location and setup to activate them.

Any pictures would be nice.

Perhaps I'm just braindead on this one, but I can't figure out where to put the switches so the get triggered, but can not be mangled by the machine driving into them...

Thanks
Paul

[DonFrambach]

I'm building a small fixed gantry router with 8020 components. Here are pictures of the Y axis and Zup switches.

[Arbo]

Good stuff, thanks.

[ger21]

You might want to try some of these, which just need to pass by a magnet, and not make contact to work.
http://www.cnczone.com/forums/open_s...made_easy.html

[Arbo]

Gerry, I like that option. Will have to read the whole thread when I get time.

[oldvan]

Don,

I like the way you used BNC cables and connectors, convenient and tidy.

John

[brtech]

The old standby is a microswitch ("snap action"), with a roller, with some sort of a projection that has ramps on both sides. The switch is mounted so that the roller rides up the ramp and trips, and can ride down the other ramp. The long axis of the switch is parallel to the axis of motion and the projection is perpendicular to the motion.

You can put two switches at either end of the travel and have the projection (which can be any material; plastic, aluminum, even wood) on the moving axis, or you can mount the switch on the moving part and put two projections on the ends of the motion.

A variation of that uses an optical vane switch, which is a light emitting diode facing a photodiode across a gap. You mount a vane so that it enters the gap at the limit and blocks the light from the photodiode. Again, you can have photoswitches mounted on either end of the axis and mount the vane to the moving part, or have the switch on the moving part and two vanes on the ends. Like the roller microswitch, the vane can pass all the way through the switch if the motion doesn't stop fast enough.

The electronic home switches work the same way, using a hall-effect magnet sensor and a fixed magnet. Again, you can have two sensors on the ends of the fixed part and a magnet that slides by the sensors on the moving part, or put the sensor on the moving part and mount two magnets on the ends of travel.

Or, you can put a nice big steel angle to stop motion, cover it with a hunk of rubber, and mount a leaf type microswitch on it so the hard stop stops the motion and the switch cuts the power at the same time