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Dusk to dawn timer

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Diver300

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I've got some low power outside lights that were previously on an electronic timer with fixed times.

Does anyone know of a timer that is programmed for sunrise and sunset so that the lights come on at night? I've found loads of dusk-to-dawn timers that turn on when darkness is sensed, but I wondered if anyone had made a device that predicts rather than senses.
 

MikeMl

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... but I wondered if anyone had made a device that predicts rather than senses.
You mean that it contains a calendar like this one?
An Arduino connected to a photo-cell could do it. You could have it "learn" the diurnal cycle by averaging the times for sunup and sunset over the last few days/weeks...
 
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schmitt trigger

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In my humble opinion for reliably turning on and off outside lights, one does really require a *good* light sensor.

For instance; if you live in an area where it rains or snows significantly.
If those weather events happen close after sunrise or close before sunset, the solar light levels will be still low enough to require to turn on outside lights.

Although one can always use a simple CdS cell, one can get a much improved measurement accuracy with the TSLxxx series of light sensor ICs from AMS semiconductor.
 

Diver300

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I appreciated that there is a lot to be said for a light sensor. Previously there was a timer that had been put in by the previous owner of the house, but obviously that would have needed changing every few weeks. The easy place to put the controller is inside, so interior light would affect a photocell.

Obviously I can run a wire and have a photocell outside, and that would be the best, but I wondered if there was a timer that would understand sunset and sunrise times.
 

dr pepper

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I seem to remember seeing something like that, it was a while back, I think it was a grasslin timer, you told it the area of the world you were in and it calculated using a built in diary light up and lights out time.
You can also get ready made photocells with a remote light sensor, or you could bung a standard photocell up outside and run the wires back inside, a timer means you wouldnt need to do this.
I seem to remember the timer I saw was used beacuse the light was under a long walkway and a photocell want a good idea.
 

alec_t

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ericgibbs

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hi Diver,
I have found that with a real time/timer and the British climate, that on some consecutive days the 'dawn' and 'twilight zone can vary as much as an hour due to the weather.
If you want the outside lights to come On when its 'dark' and Off when it becomes 'light' I would suggest a simple light/dark detector.

An LDR with a LM393 works reasonable well, my LDR is located inside a North facing window, it work just fine.

The 12F683 PIC can be programmed to read the LDR and give more precise control over the light/dark hysteresis.

E
 

dr pepper

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I have a pair of flashing blue leds in a bell box powered by a pair of AA's, they are flashing by a pic10f200, there is dusk/dawn sensing too, the only thing it uses is a photocell from the reset pin of the pic to ground, during daylight hours the pic is held reset.
 

RODALCO

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I have use an old AEG astronomical timeswitch for about 25 years, which I had to modify as it was designed for 52° Northern Hemisphere to 37° Southern Hemisphere. The clock escapement mechanism is now worn out, and I have replaced the clock now with a streetlight photocell mounted under the eave of our house.
 

KeepItSimpleStupid

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I use one for a hallway light in the house. It's on from about 1/2 hour after dusk to 11:30. Mine has a few LR44 batteries in it. I did have to replace mine once for whatever reason.

It does have a exterior button that can be depressed to turn the light on when it's off, but it's too difficult to reach being behind a cabinet. At night, there are usualy 3 light on in the house:
1. A 7W incandescent night light in the kitchen it's on most of the time)
The kitchen has a ceiling light, a light over the sink, an over the table lamp (2 of the 4 lamps are mini CFL's), a table lamp, a "hall lamp", an under the sink lamp and the refrigerator lamp. The fridge lamp is a LED based. The socket was close to unobtainium, so when it was replaced, I replaced the lamp with a LED version. The lamp itself was hard to find and had to be modified. The center connection had to have increased height.

2. the astronomic timer (CFL)

3. A night light with an LDR in the bathroom (LED)

The two reading lamps in the living room are 3-way LEDs.

My elderly mom (wheelchair bound) has a UPS on a high intensity lamp in her room. The UPS also runs the answering machine and cordless phone base station (4 phones) and is primary backup for the medical alarm.
 
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