Dragon PSU

thingiverse

The Dragon PSU is a powerful upgrade for my Reach3D printer (http://reach3dprinters.com/). However, this power supply can be used with most 3D printers if it fits your needs. I was trying to accomplish several things by upgrading my power supply. I wanted to make more amperage available to the printer, heat the bed quickly and to higher temperatures without overloading the RAMPS board, and utilize features of an ATX style PSU to remotely control printer power. This PSU is designed around specific hardware components. You will either need to use these same components or take my ideas and redesign them to fit other components. I've also designed it with a power button for easy on/off functionality. The printed parts were designed to fit the specific bullet disconnects I used, and may or may not work with others. I designed the parts to hold the printed disconnects in place with pressure. You can optionally glue them in place, but I wanted the ability to change things around if needed without re-doing the wire ends. About the wiring. While this can be accomplished without the breakout board by cutting off the end of the wiring harness and directly wiring to the harness, I opted for the board for several reasons. One, it keeps me from voiding the warranty of the PSU if I had any initial issues with it. Two, it helps easily identify where to wire the different components. Three, it provides a physical power button for the PSU. I've attached a simple diagram to help explain the wiring. The important notes are: * Inside the PSU case, wire a pair of larger gauge wires between the "DC In" on the MOSFET and a +12V and Common on the ATX board. * Wire a pair of larger gauge wires between another +12V and a Common on the ATX board to the power input of the RAMPS board. * Wire a pair of larger gauge wires from the "Hot Bed" terminals of the MOFSET to the power wires of the heated bed. * Use a pair of smaller gauge wires between the D9 terminals on the RAMPS board and the white connector on the MOFSET. Optional, for PS Control. If you wish to remotely control the PSU, particularly handy if using OctoPrint, you'll need a few additional steps: * Wire a smaller gauge wire from the "PS_ON" terminal of the ATX board to the "PS-ON" PIN of the RAMPS board. * If you wish to power a Raspberry PI from the PSU, wire a smaller gauge wire from the "+5VSB" terminal of the ATX board to the 5V terminal of the USB connector. The common terminal of the USB can be wired to a shared common at the RAMPS side. Firmware changes for PS control: The Marlin firmware will need to be updated if you wish to control the power supply. There are two lines to change in the configuration.h file. Find the line "define POWER_SUPPLY", uncomment the line, and change the value to a "1". Also, you may want to uncomment the line "define PS_DEFAULT_OFF". You can now send the M80 and M81 gcodes to power the PSU On and Off, respectively. Here's how I use this in my setup. Since the Raspberry Pi is connected to the 5V standby power of the PS, the RPi remains powered on, and since it's connected via USB to the Mega board, it remains powered up as well. However, there is no 12V power supplied to the RAMPS board, so the remainder of the printer components are powered down. I can connect to my OctoPrint setup with a web browser and using a custom button, issue the M80 or M81 commands to power on or power off the printer. Edit 1/18/2018: There was previously an error on the wiring diagram. I had mistakenly indicated the control wires from the Mofset should be connected to the D9 terminal on the RAMPS board. This has been corrected to the D8 terminal.