In this video I run through the design and build of an add-on for my DIY Prusa i3 MK2 3D Printer that controls the supply of power to the printer’s two power supplies.
I wanted to add this for two reasons. Firstly I wanted an extra layer of security in case any of the electrical components failed in a catastrophic way leading to over heats, particularly the power supplies as I doubt their quality based on the budget prices. Secondly I wanted to be able to add G code (M Code actually) to my prints so that once the print it finished the printer is shutdown, including the power supplies.
More details in the video, but as discussed here is the schematic:
Finally, if you really want to you can download my source code for the project – as it stands at this point. As explained in the video it is very much an evolution from a basic idea – so isn’t that well written. But it does the job.
I power on the printer for the first time and set up the Limit Switches, Axis Movement, End Stops, Bed Extents, Bed Levelling, Z Probe/Bed Sensor and do the Extruder Calibration!
I spent quite some time going through the Marlin documentation to see what each possible configuration instruction could do. I had already done a very basic run through of the Configuration.h file in this video/post but now it was time to get it spot on.
One side benefit of the exercise is that I can see I will need to change the way I mount the heated bed. Most importantly the nyloc nuts sitting on top reduce the Y axis extents by nearly 25%!!!!. But secondly the ply wood under the bed allows the nuts to squash the edges down too much, resulting in the opposite bed bend to that I had before! Still, good enough for a first print 😉
So before getting all carried away and wiring in the Arduino and RAMPS I thought it might be a good idea to make sure the Arduino actually works!
As I already work with Arduinos, I have the Arduino IDE installed. If you don’t you can go and grab it from here.
I uploaded a simple blinky sketch and all looks good so I also create a short sketch to wipe all data, if any, lurking in the EEPROM. Just in case it later confuses Marlin.
After downloading the latest version of Marlin I spent quite some time going through the configuration.h sketch file making some basic changes for an initial start up. If anyone is interested in a copy of that, you can download it here. (You might want to change it so my name doesn’t show up on your printer’s LCD all the time!!)
There are a lot of resources on the internet for the configuration of Marlin, here are the main ones I used:-