USB PC peripheral power saver
Recently I upgraded my PC with a new 500 GB hard disk and put the older 80 GB one in an external enclosure. I will be using the external harddisk for quick backup work, and later burn DVDs as a real backup measure. The external enclosure comes with a mains power supply. The space below my desk is now starting to look like a wall wart village because of all the mains adaptors. I have a mouse charger, printer adaptor, USB hub adaptor, camera charger, and of course the new hard disk adaptor, and who knows what the future brings. All consuming power when not in use. Because my computer takes a long time to shut down, I usually leave when it's still doing so and leave everything switched on. Sometimes I even forget to switch off my CRT monitor.
So I got the idea to build a device that switches all this stuff on and off when the computer is running. The easiest way to get power from a computer is via USB. I wrecked a cheap timer, put a relay in it and hooked up a USB cable to the computer. Well, that's the short version, really.
Click thumbnails to zoom in. Click again to zoom out, or use cursor keys to walk through all images.
Now the idea is to put some sort of delay in here so a short blackout won't cause jerking of the mains power. A diode and a big-ish capacitor should do the trick. For added coolness I added a blue led as well. The schematic: