Self-Adjusting Timer

Bill at work told me about a timer switch he installed at his neighbor’s house. Purchased at Lowe’s, the timer has a microchip that allows you to enter the time and date and the time the sun sets that day. From then on the timer will calculate sunset and turn on the light at the correct time each day. You can also program the switch to turn off at sunrise or at a certain time in the middle of the night (or put it on a 7-day timer with several on/off cycles). I have four indoor lights on timer that I adjust a few times each year as the length of the day changes. A switch like this could eliminate those adjustments. I did a search and found another brand where you actually enter your latitude and longitude so that it can calculate sunset, but entering the current time and sunset also gives you a point on the curve that can be used. I believe the one he installed was an Intermatic EJ500C. They call this an “astronomic” timer. I will check to see if I can get it locally, but found a couple of places online to buy as well:

1000bulbs.com $18.34 free shipping

Amazon $20.49

This device fits in a switch plate so that it could control the outdoor lamp which is on that switch and there is also a battery inside so that it won’t forget the time and date when the power goes off. They also make a plug-in version that I could use with my indoor lamps. These also have a “random” feature that will turn the lights on and off randomly to make it look like someone is home turning the lights on and off. But since my lights are on timer all the time my house always looks like nobody is home.

The downside, I realized later, is that these timers are not supposed to be used with compact fluorescent bulbs and all of the lights I want to control are CF bulbs.

5 thoughts on “Self-Adjusting Timer

  1. Given the energy savings of CF, this would really all be about security. Maybe you can teach the dogs to turn lights on and off somehow. Or let an Estonian move in and do it.

  2. The prohibition might be physics. With a conventional bulb you have a closed circuit with the filament that allows variable power, so dimmer switches work. CF’s don’t do variable power across a filament, so that’s why dimmers don’t work. I’m guessing this timer is in effect dimming the bulb.

    I wish the wall mount did not require a battery. That’s annoying, but then so would having to reset it. These switches should just all have little eyes that are smart enough to know if it is day or night.

  3. One of the commenters at Amazon says that the switch lets a small amount of electricity through to run the timer, but the ballast of fluorescent lights chokes that off. I’m not real sure why that trickle is needed.

    They are cramming a lot of stuff into a small package, so I guess the only way to provide backup power for the clock was with some small batteries.

  4. I got one of these today at Home Depot and installed it for use by my front porch light and carriage light. Usually a switch only connects to the “hot” wire of the circuit and the white neutral wire bypasses the switch, but this switch taps into the white wire, giving it a constant power supply. That means it will work fine with compact fluorescent and LED bulbs. They also make a smart timer that plugs into an outlet, but it uses 3 prongs and the outlets I use to control interior lamps are not grounded. It would probably work anyway, but I wanted to test out the wall switch for a while before committing to any more of these since they are kind of expensive (the wall switch was $23 and the plug-in timer is $15).

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