How to get a time-controlled dimmer switch?

January 23, 2010 7:03 PM

What's the best way to set up a dimmer switch in my room which is controlled by an alarm clock?

Hi,
So I have next to no experience with electrical engineering or modifying any electrical gadgetry. Recently however, as I've been researching sunrise alarm clocks and decided that they're just not worth the cost for me, especially considering that there's really no convenient place to put one in my room, I've been thinking about mimicing the effects using my room's main light.

How feasible do you think it would be to buy a dimmer switch and then modify it to dim-on gradually over the course of say half an hour, at a time set by an alarm attached to it?

Can you buy prebuilt alarm components to trigger a circuit at a particular time, or would I have to buy an alarm and take it apart?
Would it be better to control the dimmer switch mechanically externally, or to open it up and wire up something inside it?
Are there any much better solutions to this that I'm missing?

I'm very open to any ideas, and I think this could be a pretty fun project. I haven't been able to find anything which I can just buy prebuilt for this function, though of course I very much welcome any links to existing products if you can find them.

Many many thanks,
Luke

posted by insperatum to Technology (9 answers total)

I spent some time researching this as well, but on a lark, I tried a basic lamp timer and a regular lamp. I had both in the house, so I figured, why not? With a lower wattage lamp that's not pointed directly at the bed, it's not jarring at all and makes a huge difference. On the days I forget to turn it back on after the weekend, we can totally feel the difference.
posted by advicepig at 7:13 PM on January 23, 2010

X10 isn't a bad idea. Otherwise, I'd suggest doing something which mechanically twiddles the knob on a dimmer switch.

Circuitry-wise, a sunrise dimmer isn't complex or difficult, but without a reasonable amount of electrical knowledge you have no good way to know whether you're doing it safely. So I don't recommend it as a beginner project. Leave all the high-voltage stuff inside the sealed, UL-approved boxes for now and talk to them from outside.
posted by hattifattener at 7:28 PM on January 23, 2010

If you'd like a cool hobby project, I'd go with the dimmer switch, pull the knob off, attach a motor to the shaft, and turn the motor on with an ordinary electric on/off timer. You'd need a motor that's geared way, way down, to maybe 1 or 2 rotations per hour, to get the light to come up slowly.
posted by exphysicist345 at 7:32 PM on January 23, 2010

If you want to go the mechanical route, I suggest getting a servo motor and a USB/serial controller for it and hook it up to your computer. Both are pretty cheap and readily available at hobby supply sites (or just use google product search.) The advantage of a servo motor over a regular DC motor is that you tell it what angle to turn to rather than it being simply on-off. Once you get the thing hooked up to your computer you can really go to town adjusting when it dims and how fast and so on. You might have to learn a simple scripting language to pull this off. You could also skip the computer and use a small microcontroller like a basic stamp or PIC, but that starts requiring more and more electronics knowledge.

The X10 route is also good, and I would actually try that first before the mechanical route.
posted by Rhomboid at 12:25 AM on January 24, 2010

Response by poster: Hey again,
So I'm liking this X10 idea a lot, particularly because I'm a fairly confident programmer so it doesn't seem too daunting. That said, I'm not entirely sure that I want to have a computer running all the time. I suppose I could have my computer automatically boot in the morning and run a script to turn on the lights, which would also be handy as it would save me having to boot my computer when I get up.
Alternatively, is there any way that I could interface with the X10 dimmer directly from, say, my android phone, since that's always on anyway and I've been meaning to learn to write apps for it? If not, could I buy a cheap, low power device to sit connected to the network and act as an intermediate between my phone and the lights?
-- Luke
posted by insperatum at 1:05 AM on January 24, 2010

There are X10 timer controller devices (e.g.) that you program with the computer and then are standalone once set. I don't know if that exact model supports dimming but the macro feature sounds like it could be used to fake it if not.
posted by Rhomboid at 1:10 AM on January 24, 2010

(Or you may not even need the computer part, here's a cheap 64-event timer that supports dimming.)
posted by Rhomboid at 1:16 AM on January 24, 2010

If you're comfortable programming, an arduino might not be hard for you to work with. In which case, here and here are some threads where people discuss dimming lamps with an arduino. I don't know how well it'll keep time over a long period (days/months), though; you may need to attach something else to keep it accurate (this maybe).
posted by hattifattener at 3:17 AM on January 24, 2010

Not sure how bright you want but a BlinkM + Arduino + realtime clock module would be how I'd approach it.

If not bright enough you could daisy chain BlinkM's or go for the BlinkM MaxM
posted by wongcorgi at 12:04 PM on January 24, 2010