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As I was replacing one mechanical Christmas tree light controller that turns on/off lights at fixed times that no longer worked, it occurred to me that for next year, I could use a microprocessor like an Arduino to control the lights, and then I'm not bound by having to have the lights turn on at the same time each day.  A quick search around shows there are many potential solutions.  Most of the home automation stuff is too expensive (IMHO) for the type of application I have it mind, particularly since we have at least 4 different controllers (one outside, 3 in separate rooms) already.  Now, the control stuff I will iterate on at a later time, but I was wanting to think about what would be needed for an Arduino to just turn an A/C socket on/off.

So, the ideas I've come up with so far include:

• Buy a commercial unit that has an IR button to turn it on/off, and use an Arduino to act as the remote.  Most of these have learning circuits, so I wouldn't have to reverse engineer the protocol for the remote (which isn't hard in any case).  I would have to attach the Arduino IR emitter so that it stays focused on the control light, but that isn't hard.  Figure about $5 (US) for the cord parts.  Here is one such unit: http://www.ebay.com/itm/280848606944?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649
• By the same vein, I could use a radio based solution, though there, the problem is figuring out what type of signal is used.  I would imagine, one solution is to hack the remote control, so that it is controlled via the Arduino.
• Use a relay and make my own wiring, as in http://www.sparkfun.com/tutorials/119.  I really, really would prefer not to go hacking mains circuits wires.  Also, if you follow their advice of using a GFCI outlet boosts the price than using an IR controller;
• Adafruit offers a powerswitch tail (http://www.adafruit.com/products/268), which be ideal, but it is on the pricey side.
• I could use the X10 controllers.  I used these years ago, when I was doing a GCC port to an embedded target to control the board.  I suspect, I long since got rid of them, since I no longer had the controller when I changed jobs, so I would have to buy new versions.  However, if I had to buy new, the price kicks back up.  Also, I remember vividly that in the old days at least, once X10 got your email, they would spam it forever.

Are there other solutions I missed that don't involve me hand making cables/plugs/etc?

[Reply #1 on:]

There are various x10 vendors, some which may not spam. The cm17a firecracker seems an ideal x10 controller to use. There are some past post on the subject. A liberary file (x10firecracker.zip) has been posted for use with the arduino, but I haven't had a chance to try it.

[Reply #2 on:]

There are various x10 vendors, some which may not spam. The cm17a firecracker seems an ideal x10 controller to use. There are some past post on the subject. A liberary file (x10firecracker.zip) has been posted for use with the arduino, but I haven't had a chance to try it.

However, when I looked up X10 controllers, they were around $20 per switch.  If I can buy the other solution for $5, I need more reasons to go with the more expensive solution.  Maybe I'm looking in the wrong places.  Of course with x10, I would only need a centralized controller on my laptop or desktop, and not a separate microprocessor.

And maybe the x10 company is no longer as bad as they used to be (I have one supplier I bought an $8 cable from, and they've been sending me 3 or more emails/day, and while I block some, they keep morphing the address so it gets past the filters).

[Reply #3 on:]

Just get your X10 stuff off ebay.  It's cheaper and you won't have to put up with spam.  The problem with X10 is its reliability.  With a year to work on it, I'd take a look at the Jeenodes as an alternative for Christmas lights.  To control the power, get a relay and stuff it in a box to keep it away from children.  You can also put a relay inside a power strip to make it safer.