OHC2017 zero to firmware in < 2 hours

I thought I'd make some modifications along the way in the build, so I really couldn't do a head to head with the build time I had heard about (a lowish number of minutes). The on/off switch being where it was didn't fit my plans so I made that an off boarder and also moved the battery to off board so that I might use the space below the screen for something, perhaps where the stylus lives in the case.

I did manage to go from opening the packet to firmware environment setup, built, and uploaded in less than 2 hours total. No bridges, no hassles, cable shrinks around the place and 90 degree headers across the bottom of the board for future tinkering.

This is going to look extremely stylish in a CNCed hardwood case. My current plan is to turn it into a smart remote control. Rotary encoder for volume, maybe modal so that the desired "program" can be selected quickly from a list without needing to flick or page through things.

Machine Control with MQTT

MQTT is an open standard for message passing in the IoT. If a device or program knows something interesting it can offer to publish that data through a named message. If things want to react to those messages they can subscribe to them and do interesting things. I took a look into the SmoothieBoard firmware trying to prize an MQTT client into it. Unfortunately I had to back away at that level for now. The main things that I would love to have as messages published by the smoothie itself are the head position, job processing metadata, etc.

So I fell back to polling for that info in a little nodejs server. That server publishes info to MQTT and also subscribes to messages, for example, to "move the spindle to X,Y" or the like. I thought it would be interesting to make a little web interface to all this. Initially I was tempted to throw over websockets myself, but then discovered that you can mqtt right over a ws to mosquitto. So a bootstrap web interface to the CNC was born.

As you can see I opted out of the pronterface style head control. For me, on a touch panel the move X by 1 and move X by 10 are just too close in that layout. So I select the dimension in a tab and then the direction with buttons. Far, far, less chance of an unintended move.

Things get interesting on the files page. Not only are the files listed but I can "head" a file and that becomes a stored message by mosquitto. As the files on the sdcard of the smoothieboard don't change (for me) the head only has to be performed once per file. It's handy because you can see the header comment that the CAM program added to the G-Code so you can work out what you were thinking at the time you made the gcode. Assuming you put the metadata in that is.

I know that GCode has provisions for layout out multiple coordinate spaces for a single job. So you can cut 8 of the same thing at a single time from one block of stock. I've been doing 2-4 up manually. So I added a "Saves" tab to be able to snapshot a location and restore to it again later. This way you can run a job, move home by 80mm in X and run the same job again to cut a second item. I have provision for a bunch of saves, but only 1 is shown in the web page in the below.

This is all backed by MQTT. So I can start jobs and move the spindle from the terminal, a phone, or through the web interface.

Keeping an eye on it

The CNC enclosure now sports a few cameras so I can keep an eye on things from anywhere. The small "endocam" mounting worked out particularly well. The small bracket was created using 2mm alloy, jigsawed, flapped, drilled and mounted fairly quick. These copper coated saddle clamps also add a look good factor to the whole build.

A huge plus side is that I now also have a good base to bolt the mist unit onto. It is tempting to redesign the camera mounting bracket in Fusion and CNC a new one in 6mm alloy but there's no real need for this purpose. Shortest effective path to working solution and all that.