Yes, you can get such circuit boards at grocery stores, hardware stores and home centers. They come with a free night light attached which you have to rip apart and throw away...
Seriously, the least expensive way to get the things would be to just buy the el-cheapo nightlights and take their guts out.
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Tim Wescott
I make a night light out of wood with a 4 watt 110 volt bulb. I wanted it to turn on/off automatically so bought a cadmium-sulfide photocell and wired it up. Worked real well except that it turned the light on in the morning and off at night. I tore apart a commercial night light that plugs into a wall outlet and found a little circuit board. Does anyone know where I might be able to buy these boards so that I can get these lights to work correctly? Appreciate any info, thanks, Fred
If you get a 117V AC-relay with a changeover contact, you can wire the coil in series with the photo-resistor and operate the bulb with the normally closed contact.
"Fred" schreef in bericht news: snipped-for-privacy@storefull-3336.bay.webtv.net...
Fred,
So you're not burning the wood :)
A more or less standard circuit you find below. As you're working with 110V the maximum voltage rating of the capacitor may be lower. Let's say 250V. I'd replace the 330k by a 150k to make the TRIAC be triggered reliably. You may need to experiment a little bit as it also depends on the properties of the LDR. You may even use a pot to set the sensitivity.
No need to say the LDR should not "see" the lamp.
Unless you want to make this things in volumes, it's hardly worthwhile to design a PCB for it. A piece of experimenters board will do.
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