Raspberry Pi and Power Supply Case for MK3S

prusaprinters

<p>This is a case for a Raspberry Pi, an optional 30mm fan, and <a href="https://www.amazon.com/Valefod-Voltage-Regulator-1-5-35V-Converter/dp/B07WQJ2GD6?pd_rd_w=OcSCB&amp;content-id=amzn1.sym.deffa092-2e99-4e9f-b814-0d71c40b24af&amp;pf_rd_p=deffa092-2e99-4e9f-b814-0d71c40b24af&amp;pf_rd_r=BPJV63DNK8SYEEVJR648&amp;pd_rd_wg=7NaJj&amp;pd_rd_r=ccbb2eb8-293b-4336-9044-05a5d1d7e014&amp;pd_rd_i=B07WQJ2GD6&amp;psc=1&amp;ref_=pd_bap_d_rp_1_t">this switcher</a>.</p><h3>Printing</h3><p>Printing should be straight forward. The components are already properly oriented in the .3mf files. No supports should be necessary. Printing in PLA is <i>probably</i> OK, even in an enclosure, but PETG is suggested.</p><h3>Additional Hardware</h3><ul><li>M2.5x5mm screws, qty 4, for mounting the RPi. My stupid butt grabbed the wrong box of screws and used M3.</li><li>M3x10mm screws, qty 4, for mounting the SMPS. Shorter lengths are OK.</li><li>M3x10mm screws, qty 4, for mounting the lid to the case. Shorter lengths of at least</li><li>M3x15mm screws, qty 2, for mounting the case to the printer frame</li><li>M2.5x15mm screws, qty 4, for mounting the optional fan</li><li>M2.5 nuts, qty 4, for mounting the optional fan</li><li>M3 nuts, qty 2, for mounting the case to the frame</li></ul><h3>Usage</h3><ol><li>Mount the Raspberry Pi first. It'll take a little bit of force to get it pressed into position. I've found the USB ports to be a little on the difficult side to get into position. Install the M2.5 screws to keep the RPi in place.</li><li>Attach the case to the MK3S frame using three M3x15 screws. You'll need to replace two screws already used on the frame.<br><strong>Update: </strong><i>Do not do the bottom screw shown in the picture below. It interferes with Z-axis movement. You may be able to insert a short screw from inside of the box, I haven't tried so I don't know if there's enough clearance. I'm just rocking the top two screws for now.</i><br><img src="https://media.printables.com/media/prints/283978/rich_content/a48a66c8-cfc6-48f8-8905-9b0e94e96d8b/image.png#%7B%22uuid%22%3A%222f065596-77eb-4ee4-a4c8-1921abeaeb38%22%2C%22w%22%3A822%2C%22h%22%3A851%7D"></li><li>The frame's holes are threaded, so tighten down the screws. After tightening the screws, put the nuts on to secure the case in place.</li><li>Install the SMPS using M3 screws.</li><li>Run 24v from the input of the printer's power supply to the SMPS IN+ input. Run ground from the input of the printer's power supply to the SMPS IN- input.</li><li>Do NOT connect the output of the switcher to the RPi yet.</li><li>Apply power to the SMPS.</li><li>Press this button to toggle between showing input voltage and output voltage. The input voltage should be around 24v. The output voltage should be 22v or lower at this point.<br><img src="https://media.printables.com/media/prints/283978/rich_content/26064105-3bb9-43f5-94c2-21ebf96bd41b/image.png#%7B%22uuid%22%3A%221e60150a-8694-4205-9797-55b68d2a9c56%22%2C%22w%22%3A391%2C%22h%22%3A519%7D"></li><li>Turn the potentiometer counter clockwise (left) until the output of the SMPS is 5.0v. It may take 10-20 turns before you see the voltage begin to drop. Just keep going. <i>I'm running mine at 5.2v to avoid brown outs, but I doubt that is necessary.</i><br><i><img src="https://media.printables.com/media/prints/283978/rich_content/aafe0b99-2486-463f-9e4f-24eb6edea91c/image.png#%7B%22uuid%22%3A%22bd9a11d8-0015-45b7-a72e-ba19be3754cf%22%2C%22w%22%3A391%2C%22h%22%3A519%7D"></i></li><li>Turn off power to the SMPS.</li><li>Connect the SMPS OUT+ to a 5v pin on the RPi. Refer to the pin diagram below.</li><li>Connect the SMPS OUT- to a ground pin on the RPi.<br><img src="https://www.raspberrypi-spy.co.uk/wp-content/uploads/2012/06/raspberry_pi_3_model_b_plus_gpio.jpg" alt="Simple Guide to the Raspberry Pi GPIO Header - Raspberry Pi Spy"></li><li>If you're using the fan, install it on the lid.</li><li>Connect the fan's power and ground wires to pins on the RPi. My 5v fan was a little on the loud side so I used 3.3v and ground to power it. It doesn't move much air, but I don't really expect the RPi to get hot.</li></ol>