Shapeoko shape-up! Space to Space AM. 11PM-5AM 6/20-6/21

[Kevin Price]

Tonight's space to space AM will be dedicated to the shapeoko. The spindle definitely needs to be software controlled (started a small fire with it), the machine needs an emergency stop, and it needs to detect when it has hit a hard stop. This will involve wiring and editing the code running on the arduino. I'd also like to re-compile the gcode sender I am using with some tool tips, images explaining things added, etc. 

If you would like to learn about how to use a multimeter and oscilliscope, arduinos, relays, robotics, and open source development drop in tonight, it should be a good bit of fun! 

[Tim VanSant]

Are there any big emergency stop button switches around the space that we can use? (We could use one to mod a power strip perhaps.) I know power strips with emergency stop buttons can be purchased, but I don't have a source or price handy.

I only see three limit switches on the tool (and they seem to be disabled). Shouldn't there be six? (+X, -X, +Y, -Y, +Z, and -Z)

[Lockadoc]

There are some stop mushroom buttons in the graveyard.

Bill S

Sent from my iPhone

--
You received this message because you are subscribed to the Google Groups "LVL1 - Louisville's Hackerspace" group.
To unsubscribe from this group and stop receiving emails from it, send an email to lvl1+uns...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Kevin Price]

Tim, the hard stop switches were disabled because the inductance from the stepper motors and spindle were triggering them. I re-wired them, solving the issue with the stepper motors. They still trigger when the spindle is above 10%. I am going to put a low pass filter in line with them as Tyler suggested, hopefully keeping the noise from triggering the edge detection interrupt on the atmel. 

Theoretically you shouldn't need six in proper operation. You have three hard switches for homing, and then you have maximum extents defined in software. The machine would home itself, then "know" where it was and if it had moved too far. We can easily add three more switches as a safety feature - the software does not differentiate between which limit has been hit, so I tied all of them to a single pin - it's just a matter of splicing more wires to ground and pin 10 on the grbl shield.

I also did not realize that the spindle was 48V DC, not 24. I need to get a much, much beefier relay than what I was using. I fused it already.

For a brief minute or so, the machine was behaving in a "probably safe" manner - turning off the spindle when a hard or soft stop had been reached. Truly glorious. 

[Kevin Price]

It seppuku-ed. Again. A wire pulled out from the screw terminals on the grbl shield and made contact with something, torching the arduino that was the brains of the thing. I think the shield is working, and we have another somewhere if not. Arduinos are easy to come by. But this was why it wasn't working when I started working on it. 

At this point, I'd like to move as much off the frame of the machine as possible, re-wire EVERYTHING with shielded wire, use industrial connectors at any points that will have strain, etc. 

I'm going to be in the space during the hot-wheels if anyone wants to help me pick out cabling, connectors, and other miscellaneous parts. 

On Monday, June 20, 2016 at 7:02:46 PM UTC-4, Kevin Price wrote:

[Kevin Price]

The re-wire is complete. The hard stops are now wired with shielded cable. With Nathan's help I put female connectors on all of the wires, as well as extended them so that the arduino and grbl shield would be off the chasis of the machine. 

I could not find mushroom switches in the boneyard, so at this point what still needs to be done is:


1. Interface board for pin headers - I am making an extra board to sit between the wiring and the GRBL shield. If any noise needs to be filtered out, it can be done here. It also will allow for the easy addition of software variable spindle control to be added later, as well as coolant control. If additional noise handling turns out to be required for the hard stops, it can easily be added on this board. 

2. Layout and glue down of electronics - I have a board I am going to mount all the electronics and control circuity on.

3. Strain relief - I am going to put a large eye bolt into board next to the shapeoko and firmly attach the wiring to it so there is not mechanical strain on the female headers. 

4. Emergency stop - I could not find a mushroom button. 

Anyone is of course welcome to do any of this. Figuring out a nice way to generate G-Code would be great as well. I have been using ink scape with a plugin with very small success.