Z AXIS Home Switch Upgrade

The place to discuss your hardware and software/firmware modifications...
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pyronaught
Posts: 684
Joined: Mon Dec 01, 2014 8:24 pm

Re: Z AXIS Home Switch Upgrade

Post by pyronaught » Thu Apr 02, 2015 3:44 am

uslimey wrote:It struck me that homing the Z axis (the bed) is the most critical homing operation... I have has some inconsistency so I wanted to replace the switch with a opto... What I need to know however, is how to change the firmware to allow it to recognize a Normally Closed contact as oppose to the Normally Open one... Can this be done with G-Code or do I have to update firmware?... If I have to update firmware, where do I get it, what compiler do I need, and what should I set the optional settings to?

Any help would be appreciated.
I think the problem may not be the switch itself but the clamp that holds it to he rod getting knocked upwards. I've been meaning to print myself a new clamp that butts up against the top plate so that it can never get knocked upwards. On mine, the LED butts up against the nut right above it and I had to put a piece of tape over the leads to keep it from shorting out on the nut.

On the issue of wiring your optical switch, you should be able to make it appear both normally closed or normally open using pull up or pull down resistors, unless the electronics on the other side already have said resistors on that end. That's why I like floating inputs-- it allows more flexibility.
Experience is what you get when you didn't get what you wanted.

rsilvers
Posts: 184
Joined: Wed Apr 09, 2014 11:07 pm

Re: Z AXIS Home Switch Upgrade

Post by rsilvers » Thu Apr 02, 2015 5:07 am

I have never noticed any inconsistencies with my Z height.

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pyronaught
Posts: 684
Joined: Mon Dec 01, 2014 8:24 pm

Re: Z AXIS Home Switch Upgrade

Post by pyronaught » Thu Apr 02, 2015 3:03 pm

rsilvers wrote:I have never noticed any inconsistencies with my Z height.

Mine stays put for many prints and then just one day gets too low. It always gets off in the direction of the nozzle being too close to the bed, never the other way around, so I'm just guessing the switch is getting pushed upward since the stop bolt is never loose.
Experience is what you get when you didn't get what you wanted.

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