Using Machinekit (Linuxcnc) on a BBB beaglebone black / Cramps board with MPCNC

I’ve been working on getting a MPCNC milling setup done for the North Side Mini Maker in Chicago next week as part of a display for Workshop88 the makerspace I belong to. I had all the sub-assemblies done, but I like the new corners that just got published so I’m getting those printed out prior to final assembly.

I’m using machinekit a fork of Linuxcnc, running with Beaglebone black and a Cramps Cape. The Cramps board is similar to Ramps board except that runs on beaglebone instead of an Arduino Mega.

One thing that I’ve been doing is using something called gantrykins which splits the step signal between two polulo’s so you can basically double the amps to the motors over the current Mega setup.

This is my first attempt at something like this and there is bit of a learning curve to get this running. I’ve been keeping some pretty detailed rough notes on what I ran into and how I addressed them. I hope to blaze a trail and refactor the notes into something that might be useful to others after the dust settles after the mini-maker.

I have a Ramps/mega setup on the printer I designed and built, but I have to admit, machinekit is pretty cool and blows that away. There is whole bunch more horsepower under the hood. I still have one empty pololu slot left on the Cramp cape, and I think I may make a 4’th axis to be able to eventually add some router lathe capability to MPCNC.

I posted my work here:
(I added some ref links (there are a bunch) to the code on the stuff I didn’t understand and needed to read up on)
I basically got the dual gantries configured at this point and they seem to be working ok. There is still a huge amount of configuration that needs to be made before I would consider this done done in less than a week…(yikes)

I shot a video that should be up on the workshop88 youtube channel later on today which show’s the gantry movement which I hope to get uploaded shortly by the club.

As promised here’s a link… to my first test.

I like the idea of controlling each stepper independently, fine adjustments.

The steppers sounded like the voltage was way up on them normally I don’t hear mine at all. Are you over volting them?

I thought, the reference voltage for a DRV8824 was 1.4 volts for 1 amp… I was getting some thermal shut down and I changed it to 1 volt and they seemed to behaving better. I’m still finding my way with this stuff. I’ll having them purring like kittens soon enough…