Raspberry PI (OctoPI) Controlled Power Console for 3D Printer

thingiverse

I wanted to build a custom power control box for my Prusa i3 and lighting system using OctoPi, just like Jeffeb3's design (https://www.thingiverse.com/thing:1428478). However, I needed all four relays on the Sainsmart relay control board to be functional, along with two always-on outlets. To achieve this, I decided not to colocate the Raspberry PI 3B inside the power board and instead repurposed a CAT5 cable to carry TTL signals from the Pi to the power control box. My code was based on Jeffeb3's work, so please refer to his Thing for completing that part of the build (just duplicate commands for the other two relays). The power control box was designed using FreeCAD, which was my first time designing something in this software. Any constructive feedback is welcome. The Sainsmart relay board is secured to the bottom of the box with four M3x5 screws. The top is held in place by four M3x10 screws. To ensure a better fit, I had to use a drill to ream out the holes; however, this issue has been addressed in the uploaded design. The power cord used was purchased from Lowes and is a 14/3 cord. A drill was used to open up the power cable hole to match the size of the cord, which is secured in place with two-part epoxy. If I were to redo it, I would build some strain relief into the bottom section of the box. Internal wiring consisted of a mix of 16 and 18 gauge wire that I had on hand. The TTL signals are carried by jumper wires with Dupont connectors on one end. The top was printed in two phases by pausing the print and swapping filament in my Prusa i3 Mk2. Matching up the GPIO outputs from the OctoPi to the wires in the power control box took longer than expected, requiring a lot of trial and error. It turned out that the cable was labeled as 568B but was actually a 568A cable. I used Dupont connectors to connect to the OctoPi (https://acuitysupport.zendesk.com/hc/en-us/article_attachments/203181108/T568-1.png). The parts used and their links are below: Jumper Wires: https://smile.amazon.com/gp/product/B01L5ULRUA/ref=oh_aui_detailpage_o04_s01?ie=UTF8&psc=1 RJ45 Connector: https://smile.amazon.com/gp/product/B00IO3HB2K/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 Dupont Crimp Connectors: https://smile.amazon.com/gp/product/B014YTPFT8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 Crimping Tool: https://smile.amazon.com/gp/product/B00OMM4YUY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 Sainsmart Relay: https://smile.amazon.com/gp/product/B0057OC5O8/ref=oh_aui_detailpage_o05_s02?ie=UTF8&psc=1