I'm finalizing my plans to make a physical control panel to interface 2 of my 3D Printers to an embedded Linux device. (Just minimal physical controls since 95% of the controlling will be done via a web browser rather with physical buttons.)

Each printer will have it's power supply controlled by the mCU, and about 20W of LED lighting.

One printer is powered by an ATX power supply that is also powering the mCU with it's +5V standby power. The other printer uses a non-ATX SMPS that has a PWR_ON pin similar to an ATX PWR_ON pin. (IOW, floating or high = PSU off, low = PSU on)

My main concern is whether simply connecting everything to a common ground is sufficient to keep each PSU and the mCU safe as the two power supplies kick on and turn off.

Am I missing anything needed to keep the three main components reasonably safe? Schematic of the controller

  • \$\begingroup\$ What are your worried about? Ground bounce? Is there reason to believe your ground isn't solid? \$\endgroup\$
    – Voltage Spike
    Feb 16, 2017 at 5:54
  • \$\begingroup\$ @laptop2d I'm mostly worried about things beyond my knowledge. Transient spikes, back currents, etc. that I don't have the experience to plan for. Things that might fry one or more of the components. I'm not worried about ground bounce, because that can easily be taken care of with software debouncing, and I'll also probably throw in some 100nf capacitors across all of the switches for debouncing. Which reminds me that I ought to throw in some isolation caps near the mCU, and in the control box. \$\endgroup\$
    – SvdSinner
    Feb 16, 2017 at 15:28
  • \$\begingroup\$ Get an EMC engineering book, I'm not going to make a recommendation (there is one that I recommend but I've done it so many times its almost advertising). Giving recommendation on those all of the items that would need to be covered is too broad because it can't be contained in one answer and is very much dependent on your design, the cabling and the grounding scheme. Does this need to pass regulatory? \$\endgroup\$
    – Voltage Spike
    Feb 16, 2017 at 16:50
  • \$\begingroup\$ @laptop2d Not at all. This is just a home project that I want to keep reasonably safe. I'm moving my 3d printers to another room, and want to have the ability to power them on/off, and observe them via webcam (which is what the lighting is for) so I don't constantly have to walk across the house to check on them. \$\endgroup\$
    – SvdSinner
    Feb 16, 2017 at 19:41


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