The whole point of this Instructable was to allow me to power on all the accessories for my computer without thinking about it. And then not power all the little power vampire wall warts when I am not using the computer. The idea is simple, you power on your CPU, all of the other parts of the system power up (monitor, laser printer, speakers, etc) When you power off your CPU, they follow suit.Now there products out there that will do this for you, and if you do not have the experience working with line voltage electricity, please stop reading and just go buy one. There are several products that do exactly what we are trying to do here, but of all the ones that I have reviewed have disadvantages over the device that we are going to build. They fall into three basic types:
There are cheap usb controlled power strips, but I have seen several that do not offer any isolation, and if you are creating a possible path for line voltage (120v here in the USA) to your mother board, and its many hundred dollars worth of over-clocked goodness. I would like some isolation.
There are current sensing power strips, One of the outlets is set up to sense current flow. When this happens the electronics in the power strip power on the other outlets. Its a good idea, but sometimes they do not sense correctly, and will not turn on the accesories. Also the electronics require yet another little power supply to be on 24/7, this we are trying to avoid.
There are well designed enterprise grade solutions with isolation, that work very well and have a very hefty price tag as well.
This circuit uses no extra power when it is not in use, and offers some hefty isolation from power surges, and does not cost a fortune to build.
Step 1: What You Will Need
First off if you do not feel confident in your ability to work with line voltage power, please stop reading. If you build this project wrong, you have the ability to destroy your motherboard on your PC. I'm not kidding.
The heart of this system is two things really, the actual switching is done by a DC controlled solid state relay, All the isolation is provided by a pair of fuses and some transient voltage surge supressing diodes (TVSS)
All of the other parts are really up to you, I used what I had kicking around. Which was mostly standard electrical fittings, and an old plug strip, and a heatsink from a junk processor, and a USB cable that was miss ordered with usb "A" connectors on both ends. Feel free to use whatever works for you.
All told the parts that I had to order (fuses and holders, TVSS, and Solid State Relay) were less then $30.00 USD from an online supplier.