DIY “Smart” Power Outlet

A long time ago (a little over three years ago), I wrote a post about how I modified my PS2 with a hard drive and some software that would let me back up games I owned to a hard drive.  The benefits being I have my entire game collection at my finger tips, as well as it saves the dvd laser (an extremely costly replacement if it ever goes  out).

Well I found a way to do this same thing with my Wii!  Rather than having an internal hard drive (or SD card in the Wii’s case), it uses an external hard drive attached via USB.  As a side note, the Xbox 360 has this feature built into its system rather than unfairly punishing its client base by saying such software should be outlawed.

Anyway, soap box ranting aside, I have it all set up in my fireplace shelf I set up (as seen in my last blog entry).  The only issue is that I really like the curtain my wife made and it’s a hassle to move it back and flip on the hard drive when EVERYTHING else is automated.  I even used a special type of remote (JP1, a subject I’ve also talked about previously) that I programmed the elaborate sequence needed to turn on the various devices in my entertainment system.

I could have left it on all the time but A) That’s a  waste of electricity and B) The external hard drive enclosure I use is passively cooled (it doesn’t have a fan on it).  It get’s a little toasty in my fireplace shelf and having the hard drive on for a couple hours makes it hot to the touch, so leaving it on 24/7 seemed like a very bad idea to me. 

So I began to search for for a power strip or outlet that would automatically turn on when the Wii turned on.  I was able to find some eventually, but they all cost in the range of 30+ dollars.  That’s when I decided it was about time to get out my DIY tools!

I knew my basic idea, I want my hard drive to turn on with the Wii, but the Wii doesn’t really have a lot of external outputs that I can work with… pretty much just a pair of USB ports really.  Well thanks to my job with Prime Controls, I’ve learned a lot about relays and there in was the solution to my dilemma!  I set out to purchase a Solid State Relay that would activate whenever USB voltage was present (or for those who care about the technical side of it.  I needed a SSR that would output a range of AC power that included the 120V AC put out by your every day home power outlet, and whose triggering input voltage covered the 3-5V DC power provided by a standard USB plug.  I know technically USB puts out 5 volts, but I didn’t want an under voltage on my USB to mess up my whole project.)

The only catch was everywhere I looked all the SSRs ran in the 20 dollar or more range.  All things considered, I suppose that’s not too bad a price, but it’s more than I was willing to pay.  If it would cost me $20 to do it myself, there’s not much point in not shelling out an extra 10 bucks to buy a fancy pre-made one.

In desperation I went to Fry’s Electronics, only to be met by a trio of dumb stares from clerks who had never even HEARD of an SSR, and they all work at a desk literally 5 feet from the relays!  Fortunately, one of the workers referred me to an electronic shop called Tanner’s Electronics.  I WILL be remembering this place.  It’s pretty much what radio shack and Fry’s both started off as before they ditched the small electronics and knowledgeable employees in favor of over priced wires and minimal wage high school kids.  It’s AMAZING.  They had what I wanted for 8 bucks.

So I spend some time assembling it all this evening.  I took one of the many printer USB cables I had lying around and cut off the printer end to provide triggering power for my SSR (it tells my relay to turn the switch to the on position).  Then I repurposed a computer power cabled to provide the AC power to the outlet.  I opted for a single outlet rather than a whole power strip because I didn’t need a whole power strip taking up space.

Here’s a photo of the final set up.

You can see both the AC plug and my USB cable.  They go into the first box where I have the SSR mounted to the lid of the box.   I had heard that SSRs need a heat sink to work without over heating so I’m using the box to act as a heat sink.  I also applied a good amount of thermal paste between the box and the relay to aid in getting rid of heat, but so far it doesn’t seem to generate much heat… but the amount of power I’m pulling down it is pretty small so I’m not too surprised.  Finally, the last cable goes from the SSR to my little outlet box.  Anything plugged into those outlets will only turn on when power is going over the USB cord.  Which of course means if I ever wanted to, I could just plug a power strip into one of the outlets and have my very own “Smart” power strip.  Total project cost?  Under $20 if you had to buy all the stuff I already had on end, for me I think it cost under $15  (and it was only that much since I had to buy the two enclosures rather than fitting it all into one box).

DIY “Smart” Power Outlet