I was happy enough with my single printer connected to my computer and controlled directly from my slicer over USB. The majority of the things I print are of my own design, so when setting up the printer it only seemed logical that I would have it connected to the machine I’d be doing raspi bitcoin stock designing on. If I’m sitting at my computer, I just need to rotate my chair to the right and I’m at my printer.
But things got tricky when I wanted to set up a second printer to help with speeding up larger projects. I couldn’t control them both from the same machine, and while I could print from SD on the second printer if I really had to, the idea seemed painfully antiquated. I wouldn’t have to fiddle with re-leveling the bed after moving it around. Perhaps most importantly, I knew there was plenty of room available in the base of the machine so I wouldn’t have a problem fitting additional hardware in there. My research told me that the Pi Zero wouldn’t have the zip of the Pi 3 when it comes to slicing STLs, but that didn’t seem like too bad of a trade-off given the small size and reduced power consumption. I was specifically interested in low current draw, as I wanted to run the Pi directly off of the expansion port of the Printrboard, which I knew had a 5V regulator that’s only rated for 300 mA. Everything I read online told me this wouldn’t be a problem for the Pi Zero, especially since I could turn off the HDMI port as it would be running headless.
This first test was very promising, it showed that the Pi Zero seemed to top out at about 180 mA when performing resource intensive tasks such as slicing or updating packages. I did need to disable HDMI output to get the power consumption this low, but as the Pi would be installed inside of the printer and never needed to get connected to a display, this really wasn’t a problem. Feeling confident, I soldered some headers to the Printrboard’s expansion port and the Pi’s power pins, and connected them with a couple of jumpers. Upon close inspection, the Pi’s power indicator light seemed to be showing it shutting down during the booting process. After renabling HDMI and hooking it up to a display, sure enough it would get to a certain stage and then restart.
RC vehicles to convert the main battery down to 5V for the radio receiver. With micro-sized quadcopters all the rage anymore, it was easy to find one for a few bucks that’s only a little bit larger than a peanut. While I had hoped to do this project without permanently attaching anything to the Printrboard, I had to suck it up and solder the BEC module’s leads to the underside of the PCB where the main power connects. The other side of the BEC module has a standard servo connector, which I was able to plug directly into the Pi’s GPIO header. So at least I can still take the Pi out of the printer if needed. The BEC module can be seen between the Printrboard and the center stepper motor.
The Pi itself is screwed into a 3D printed mount I designed. I planned on drilling holes in the case and screwing the mount down from the other side. But right before I popped the holes through the steel, I realized the screw heads would interfere with the movement of the bed so I had to settle for double-sided tape. Even if you’ve never touched a Raspberry Pi or Linux before, you’ll have no problems getting the software up and running. STL and G-Code files stored on the Pi. But you’re almost always going to be better off doing it in Cura on your desktop and sending the sliced file over. But the option is there, and if the STL isn’t too complex it works well enough.