Prusa i3 OctoPrint power button and fan control

prusaprinters

<p>I personally did not want to leave on my Raspberry Pi 4, running an instance of OctoPrint, all the time. Therefore, I decided to create a power button to attach to my i3 frame. While designing and testing I also realised that I did not want the fan to be turned on all the time either, so I included a NPN transistor as well!</p><p>&nbsp;</p><h3>Required items</h3><ul><li><a href="https://www.3djake.com/3djake/threaded-inserts-50-piece-set">M3 threaded inserts</a>, from 3DJake</li><li><a href="https://www.amazon.de/gp/product/B07YSFGSLG/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&amp;psc=1">M3 screws</a>, 16mm long, I had laying around</li><li>5-pin JST connector, male and female</li><li>1x3 and 1x4 female Dupont connectors</li><li>680 ohm resistor</li><li>PN2222A NPN transistor</li><li>Momentary push-button</li></ul><p>The resistor and transistor can of course be switched out for something similar, depending on what you have laying around. I have also added a wiring schematic. As you can seem only 4 out of 5 pins are connected.</p><p>&nbsp;</p><h3>"Coding"</h3><p>To get everything to work, you have to add the following lines of code to /boot/config.txt:</p><pre><code class="language-plaintext">dtoverlay=gpio-shutdown,gpio_pin=3,active_low=1,gpio_pull=up dtoverlay=gpio-fan,gpiopin=4,temp=55000</code></pre><p>The first line configures the power button. The second line turns the CPU-fan on when the CPU reaches a temperature of 55<strong>°</strong>C. The temperature and GPIO-pins can be adapted, depending on your configuration.</p><p>&nbsp;</p><h3>Print instructions</h3><p>All models were printed in PETG at 0.2 mm layer height and 15% infill, oriented according to the 3mf-file.</p><p>&nbsp;</p><h3>Other prints</h3><p>For my <a href="https://www.thingiverse.com/thing:4111980">Raspberry Pi 4 case</a>, I have used a model from Thingiverse by <a href="https://www.thingiverse.com/brawfx/designs">brawfx</a>. I have removed some of the honeycomb pattern to fit the larger Dupont-connector.</p><p>The <a href="https://www.prusaprinters.org/prints/46866-prusa-mk3s-mk3s-pi-camera-v21-mount-with-optional-">camera mount</a> I used was modelled by <a href="https://www.prusaprinters.org/social/65748-tinkrmakr/prints">TinkrMakr</a>.</p><p>&nbsp;</p><h3>Final remarks</h3><p>I hope this print can be useful for others the way it has been for me. Any remarks or ideas for improvement are always welcome!</p>