OK, so I have LEDs lighting my structures. If I want to power each building with a 12 volt Li-on battery, what type of “Photo-cell” would I need to automatically turn the lights on. Most of what I have seen is for higher voltages like 120 house current.
not sure you can use a simple resistor type and get good battery economy.
I’d look for a small solid state “switch” with a photocell.
Greg
Dan - if you aren’t drawing too much power with your LEDs (less than 100 ma) this circuit should work for you - it is made up of a CdS light sensor (labeled LDR), a transistor and a few resistors.
I use this circuit to kill the lights in various areas on the Children’s Hospital layout when the house lights come up - when the lights go down they light back up.
The 50K pot is used to adjust sensitivity. You will need to adjust the value of the 470 ohm resistor that is in series with the LED to match your setup.
If you need to deal with more current you can substitute a Mosfet or Darlington for the 2N2222 transistor.
When off the circuit only draws about 1ma so your battery life should be good
dave
(http://www.trainelectronics.com/temp/CHP_LightsOffInDay_LDR.jpg)
Thanks Dave. However I am far from understanding electronics. I’m a kind of “Plug & Play” person.
Dan - you may want to check this one out - it is already put together
dave
Dan - It might be worth leaning how to put together a simple circuit. David’s circuit is probably less than $5 in parts Vs almost $15 for a pre-made board that you still have to solder wires on.
Jon Radder said:
Dan - It might be worth leaning how to put together a simple circuit. David’s circuit is probably less than $5 in parts Vs almost $15 for a pre-made board that you still have to solder wires on.
Jon, I know you’re correct about learning simple electronics. But the time or the inclination is just not there yet. Too many other irons in the fire all of the time.
David Bodnar said:
Dan - you may want to check this one out - it is already put together
dave
Thanks Dave. Looks like a plan.
Bakatronics is a good source for this type of thing. I have used quite a few of their items.
Night activated, $11 -
http://www.bakatronics.com/shop/item.aspx?itemid=447
Night activated with timer, $20 -
http://www.bakatronics.com/shop/item.aspx?itemid=600
-Brian
Brian - those are good alternatives but I tried to avoid relays in my recommendations as they are sure to draw down the batteries Dan is using faster than his LEDs!
dave
David Bodnar said:
Brian - those are good alternatives but I tried to avoid relays in my recommendations as they are sure to draw down the batteries Dan is using faster than his LEDs!
dave
Interesting side note, Dave, this past holiday season I picked up two short strings of LEDs powered by a 2 AA battery pack for $4 each at a local drugstore. We strung them around a couple of little spruces. The pack had the option of solid or blinking lights via a SPDT C/O switch. One string worked fine, the second was DOA. I took the non working box apart rewired the switch for on/off and removed the blinking circuit transistor. The lights worked fine after that but I found the first string would last 4 days on the batteries and the newly rewired pack ran 8 days. Next year the first pack gets rewired.
-Brian
Dan: maybe you might want to take a look at using some solar power garden lights like these: http://www.walmart.com/ip/Sunforce-Solar-Powered-Garden-Lights-10-Pack/15063168
You could find a place to hide them but still allow then to get enought sun to charge the NICAd battery inside. You could run a wire from the circuit board where the LED is attached to the building you want to light up.
These are cheap and easy to rewire and they automatically come on at night.
Dan S.
Good Evening Dan,
That thought crossed my mind. However I’ve been there before and wasn’t totally satisfied with the results. Futhermore the light emits to the side which in my opinion distracts ones eye from the subject. Lastly, I have been in a Walmart exactly twice in my life, which turned out to be exactly two times too many. No reflection on anyone here that does shop there.
I’m still on track with using LED lighting and making my lamp posts from scratch. However, I have two LED drivers that have been sitting unused in my garage. Actually, I recently remembered they were there. I also have a Dusk to Dawn sensor switch for 120 volts. It is slightly more wiring than the battery method but less to maintain.
I found these LED lamps on Ebay; http://www.ebay.com/itm/281068514164?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
They will fit nicely into a piece of 1/2" CPVC tubing. I plan on building the lamp posts with the light facing the ground. This way I can place them at stations, yards, etc. to light up the subject matter. I’ll post some photos when i get started.
Dan: I hear where your coming from. I guess I didn’t quite get my idea across. I wasn’t suggesting that you use the solar power lights as they come in the package, but rather remove the LED inside it and replace it with wires running to the LED lights in your structure. If you make the wires long enough you can hide the solar light somewhere out of the way, but in a place that it can still get enough sun to recharge the battery. That way you can use the LED lamp post to your liking and still have them turn on when it gets dark and let the sun power them for you.
Another alternative would be to get a large solar panel that puts out 12Vs and have it charge a deep cycle Golf cart battery and then use it to power all your LED lamp posts. Thats the way I am going to go. I have several solar panels on my garden shed roof that charge a deep cycle battery. The panels are connected to a charger and then to the battery. The charger has a load output connection that will be connected to the LED lights. I haven’t decided yet weather I am going to put a photo cell in somewhere and have them come on automatically or just have a switch in the shed I can flip and turn the lights on.
In any case the one Deep Cycle Golf cart battery will power all the Lights I will have with tons of power to spare.
Dan S.
I like your solar panel idea Dan. I’ve seen simple panels advertised at Harbor Freight. I must study up on the whole solar panel subject in order to get a better understanding of the technology.
Dan: Here is something that might work for you and will allow you to use your 12V LI-IOn battery. It is listed on Evilbay, but it could be what you are looking for.
Item number: 360589015162
Check it out and see what you think.
Dan S.
Dan Padova said:
I like your solar panel idea Dan. I’ve seen simple panels advertised at Harbor Freight. I must study up on the whole solar panel subject in order to get a better understanding of the technology.
Dan - this article on solar lighting may help - please note that the Harbor Freight solar panels mentioned in the article have not held up well over time - those from VW have worked very well.
http://www.trainelectronics.com/artcles/Solar_power_4_LED_lights10-29-04.htm
dave
Davie, I looked on ebay, $15 yes, but with $30 shipping… Twice the amps and twice the cost apparently, and they look twice the size.
There were older ones (different design) and many were from 2002, 2003 …
What is your opinion on 10 years on one of these things?
I’m interested to buy, but could you tell us how long yours has lasted and if you know the date of manufacture?
Thanks, Greg
Dan,
To go off the other Dan’s idea of solar power. I got the idea from Kevin Strong. I bought some really cheap solar yard lights. I took the housing apart to get to the electronics. I am now in the process of remounting the lights in the buildings and then I wired extra long wire that extends to a box I am mounting on the fence that has the solar panel from the light. It is really easy and really doesnt require much electronic knoledge except clipping the small wire between the panel and the light and then splicing a longer wire in at the cut.
Jake Smith said:
Dan,
To go off the other Dan’s idea of solar power. I got the idea from Kevin Strong. I bought some really cheap solar yard lights. I took the housing apart to get to the electronics. I am now in the process of remounting the lights in the buildings and then I wired extra long wire that extends to a box I am mounting on the fence that has the solar panel from the light. It is really easy and really doesnt require much electronic knoledge except clipping the small wire between the panel and the light and then splicing a longer wire in at the cut.
Hmmm, sounds like another option. I’ll keep it in mind. Although I must say, there’s not much room up there…