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:
- Micro USB cable
- USB Type A female breakout board (optional, you could just solder directly to a USB connector, but I’m not going to show you how here.)
- Wire, solder, soldering iron
- ATX breakout board and ATX connector (optional)
- 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.
- 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.)