This is the heart of the beast - the actual hardware to control the outlet.
My version is in a nice little case that I scrounged from my father's junk pile... I've got a kitty cat, and I think 120V 50AMP adds up to just a little over 9 cat lifes, so it's better safe than sorry with this thing.
The main part is a special "relay". You can pick these up on ebay for pretty cheap - you could try your local electronics store, but I honestly doubt you'll have much luck. None the less - you'll need it.
So, let's do an inventory of what you'll need for this part: - Tools - Utility Knife - Soldering Iron - Solder - Electrical Insulating Tape - Items - Opto Relay Model # (480D10-12) - Extension Cord, 4ft(You'll be cutting this, so it shouldn't be your dad's/friend's/neighbour's or something) - Safe (non-conductive) housing for the relay - Parallel Port cable'
Ok, that's pretty much it. You can see I used some fancy eye-couplings for mine (or whatever they're called)... that's where the soldering iron comes in handy - but you'll also need it to re-attach one of the power lines on the extension cord when you cut it.1.
Simply take your extension cord and cut it - keep in mind when you're doing this that where you cut is where the relay will be placed and housed. So if you need some distance to get to the outlet, cut it towards the other end. I didn't consider that when I made mine, but I got lucky.
Now, figure out which line of the two cables you cut is the lead(positive) and which is the negative. The relay is marked which connects to which, but if you don't know anything about power outlets or extension cords this may be tricky. Good luck! :P2.
Take your eye-couplings and soldering them to the ends of the wire and crimp them so they don't come lose. Don't solder up the other wire (in my photo you can see it has black tape on it for safety) - you'll need to keep those unjoined if you want to put it in a case.3.
You'll want to refer to a guide about your parallel cable, or just test it with a current tester (to determine which pin is 1). Here's
a link to the wikipedia entry on parallel ports.
This is really important - all of the software I've made is configured to run on pin 1. I should mention, again, that there are 8 pins on the parallel port to control a relay with... that means 8 unique items to control... if you don't mind buying 8 relays :P4.
So you've got your hardware done and you need to test it, right? Ok - that's good. I got to that point to, I used this
great program. The webpage is in German, so uhh... here's the direct link
Once you've determined that you've got a good connection and it's turning your appliance on/off you'll want to head down to the last step to check out the software I had made to control this. If you're having trouble following these steps at this point, please - PLEASE leave a comment.
If you're ready to kick this instructable into TURBO CHARGE
then head on to the next step.I love improvement, and I'm a fan of criticism. So I'll update the instructable as I get suggestions or complaints. If you notice I did anything dangerous or stupid, don't hesitate to mention it - you could be saving someone a lot of trouble.
Here's a video I made a few months ago when I was still "debugging" the relay. Hopefully it will give you some insight into the simplicity of this project, or any questions you have.