Tuesday, January 7, 2014

Safety First- Remotely Monitoring and Killing Your Jobs on the Cheap

I am always nervous about leaving my printer printing when I leave the house because I have these visions about it suddenly bursting into flames. I have wired a lot of things for 120 V but until I can get a UL certification on my home built printer I am never going to be perfectly comfortable with my wiring job. This culminated last weekend when I had a date with my fiancĂ© that I had to leave for but the print wouldn't be finished for another few hours. I wanted a way to remotely monitor the job and kill the power to everything at the end.  Unfortunately, I did not have it and the fear of the unknown sat in the back of my mind the whole night until I finally got home and saw that everything had finished normally.

For those wondering, there is a way in the G-code to cut the power to everything after the print finishes but I like redundancies. Here is what I add in Slic3r under the Custom G-code section:
G1 X12.0 F4000
G1 Y170 F4000
M104 S0- Set the extruder temperature to 0
M140 S0- Set the bed temperature to 0
M84- Turn off idle hold on the motors

To prevent this nervousness from happening again I wanted a way to remotely monitor and cut the power to everything if something happened. I had seen a lot of great work done with Octoprint and a webcam but since wiring a kill switch there required additional wiring and a relay that I was going to have to do myself (and thus was not UL certified), I wanted a commercial option. I went with a wifi enabled WeMo switch that the printer plugs into and you can control it remotely from your iPhone. This works even over 3G/LTE so you do not need to be in the same network.
WeMo wifi enabled switch.

The web interface is pretty slick too. You can turn off the printer manually or there are additional rules so you can have it turn on/off to correspond with the time of day, when the sunrises, or other rules. I bet this could help with workflow if someone wanted to have a printer turn on and automatically warm up the heat bed before you got up but that is far more use than I have for my printer at the moment.
WeMo iphone interface.

The next logical piece is adding the webcam functionality. Although the idea of using Octoprint to automatically slice and then submit jobs is pretty amazing, I didn't feel like forking over the $90 for the hardware and instead went for the less expensive iCam program on my iphone ($5). It works by streaming your webcam over to the iCam servers and then you can connect to it on your iPhone or Android device.
Mac OS X interface for streaming the progress of your printer.

iPhone interface for monitoring the print.

Together these work pretty well and I'd recommend it to anyone who wants a cheaper plug and play option to monitor their prints.

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