2-channel relay housing

prusaprinters

<p>I needed a way to control my print chamber temperature and lights from my Raspberry Pi, so I threw together some spare bits and pieces I had lying around and constructed this little relay housing. It uses two single-channel 5V relay modules to independently control the top and bottom sockets of a standard outlet. </p><p>Because the relay modules have nice little indicator LEDs built in, I also designed some light pipes to bring the state information up to the front panel. I used a short piece of transparent PETG filament cut flush with a razor blade at the top of the printed lightpipe housing. This takes advantage of the property of [total internal reflection](https://en.wikipedia.org/wiki/Total_internal_reflection) to direct the light efficiently from the LED.  I was surprised at how effective it was—in the second photo, both modules are powered, but only the top one has the filament installed! It's important for the end of the filament to be as transparent as possible, so make sure to cut with a razor blade instead of flush cutters.</p><p>I also included a little cable gland strain relief I'd designed for a different project. It fits snugly on a 7mm-diameter round cord. You may need to fiddle with XY-compensation settings in your slicer, depending on your particular printer's tolerances. </p><p> </p><p>Parts used:</p><ul><li>[5V relay modules](https://www.amazon.com/gp/product/B07M88JRFY/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&amp;psc=1)</li><li>[3.5mm stereo jacks](https://www.amazon.com/gp/product/B089222S84/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&amp;psc=1)</li><li>[power cord](https://www.amazon.com/Bergen-Industries-Inc-PS313163-Appliance/dp/B07BQCMPF2/ref=sr_1_5?dchild=1&amp;keywords=ac%2Bcord%2B3%2Bprong&amp;qid=1615407723&amp;sr=8-5&amp;th=1)</li><li>[decorator receptacle outlet](https://www.amazon.com/Legrand-Seymour-radiant-885WCC21-Duplex/dp/B000UPGKZY/ref=sr_1_2?dchild=1&amp;keywords=outlet+decorator&amp;qid=1615407831&amp;sr=8-2)</li></ul>