When your desktop computer is asleep, it’s still drawing a small amount of power over 5V standby on its ATX power supply. When you wake the computer, it will turn on the rest of the power supply. We can take advantage of this feature to power an always-on raspberry pi or arduino that can turn devices connected to the rest of the power supply on or off (explained in a another tutorial soon.)

Supplies you need:

  1. You need to a connection to 5V standby on the ATX connector, and GND. See this chart, if you’re not using the breakout board. You can either cut the wire on the ATX cable and solder a longer length to it, or solder a wire directly to an ATX connector in the appropriate places. If you’re using the breakout board, it’s easy, just solder the wire to GND and 5V standby.
  2. Solder the cable connected to 5V to VCC on the USB breakout board. Solder the GND cable to GND. You don’t need the other holes, they’re for data and we’re just using power.

That’s it, plug in your 5V device to the USB port, and then turn on your PSU. The device will always stay on. This will let you turn the rest of the PSU on/off remotely (more about this in another tutorial later.)

There’s a few advantages to powering your Printrbot Simple with an ATX power supply instead of the laptop power supply it came with:

  • You can add a heat bed (assuming you get a big enough power supply, 350W should be enough.)
  • If you want to set up a Raspberry Pi with a camera and run OctoPrint, you can power the Raspberry Pi from the power supply, such that the Raspberry Pi is always on, but the printer is not. You can then use the Raspberry Pi to turn the printer on and off remotely.
  • If you want to add a computer fan for ventilation/filtering fumes, you can power that also with the PSU

There are other ways to do this, but this is just how I did it.

Things you need:

  1. (Optional Step) Put together your Power Tower, but leave the side off with the notch for the cables.
  2. ATX power supplies were designed to be used in desktop computers, so you’ll find that if you skip this step and do all the other steps, the Printrbot won’t turn on. The reason I used the breakout board is because it’s nice and labeled and I don’t need to worry about the jumper cable falling out, and I didn’t want to cut the cable when I added a usb port to power my rasbperrypi (there will be a tutorial on this later.) I’ll explain how to do it both ways, though. If you’re not you’re not using the breakout board, you need to look for the green wire (the PSON wire), and connect it to any black wire (GND) using the jumper cable and that’s it. If you’re using breakout board, solder the ATX connector to the board, and then solder PSON to GND.
  3. Connect the Y connector to 12V. 12V is all the black and yellow cables. Brook Drumm made a video about this for the Printrbot Jr, but it still applies here.
  4. Connect the power extension cable to the Y connector. If you’re using the Power Tower, run the extension cable through the notch, and finish putting the tower together.
  5. Remove the power connector from the Printbot, and connect the power extension cable instead. You should be able to fit this through the hole where the power connector was but kind of flattening the cable and gently pushing the wires through one by one.

Now, when you turn on the PSU switch, your Printrbot should turn on!