Control circuit to switch on LED's at dusk

[(unknown)]

Hi All

I'm totally new to here but I have an idea to build (for starters) a small solar charger that will power a 12 volt led lamp which would switch on at dusk and off again at dawn. Does anyone have a circuit diagram for a unit like this? I've googled the net but found nothing. Also, would I need a charge controller for a simple circuit like this? Thanks in advance for any help/advice that anyone can give me on this.

[RogerAS]

Easy!

Look at my files. I have a tracking circuit that uses photo resistors and op amps to drive the tracking. You don't need all the other stuff.

All you need is a single op amp like a 741 and a photo resitor and one mosFet. Drive the circuit with the rechargeables that will power the LEDs.

Do a net search for light sesitive circuits if you don't like my little thing or can't figure it out.

Hoping to help.

[etownlax]

http://www.uoguelph.ca/~antoon/circ/actrelay.htm

Take a look at that... might be something you would want.

I don't think it takes much power. to run.

Even simpler would be a photo transistor and a battery and relay all in series.

-Randy

[etownlax]

well something like that... (that would turn it on during the day(not what you want))

-Randy

[richhagen]

I have built a similar comparator circuit with a low power op-amp and it has performed reliably for a long time.  There is a cadmium sulfide light variable resistor on one of the legs, and two high value resistors as a voltage divider on the other.  It draws a fraction of a milliamp when off.  All it turns on is an LED, but one could run the output to a FET to power a larger number of LED's.  Rich

[FishbonzWV]

Diskman,

Unless you just want the 'thrill of victory' for building your own, look at this.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90729

It's on sale now for $4.99.

It probably isn't 12v but you could reverse engineer it for the layout. I don't think it's got a contoller in it...they just sized the batteries and PV for a full charge over the daylight hours.

Shoot, you can't even buy the nicads for 5 bucks.

I've got one and it stays lit til dawn.

Fishbonz

[ghurd]

Small 12V solar goes great with a PB137ACV. Cheap and simple.

I think this will work for the switch.  Didn't try it. It is a cross between several online versions.

Might need to right click the graphic and choose 'view image'.

G-

[la7qz]

Hi

Take a look at this post:

http://www.fieldlines.com/story/2007/5/19/51832/4098

Regards,

Owen Morgan

Yacht Magic

St Martin

[nothing to lose]

Sorry Fishbonz,

 I got friends and others do to.. "can't even buy the nicads for 5 bucks" der many can't but many are less than free! LOL

Thank you oh holy Sub-C Bruce Almighty

[Bruce S]

Nothing to lose;

   Ha ha, don't hold me up that high :-D

Fishbonz If you or others who would like to try some of these. Just leave me a note hear and I'll gladly send them over.

However: NTL is the guru on soldering them as well as making LED light posts out of them.

NTL post a few pics so others will be inspired :-)))

Personally I like the older ones, they're built 4x4 using sub-c and are much easier to re-wire.

NTL , Sorry for the long wait , had personal biz to attend :-(

Cheers

Bruce S

[ghurd]

(Glad you are back)

[Bruce S]

G-

Thanks for the shoulder too...

Bruce S

PS, did you find those parts? I need to order 3 more of those controllers.

If you have the time, try hooking up one of those steppers like the one you sent to me, use a quick little adding circuit so the ouputs add togther and send it into a LM317 with the output fixed. Send that into one of your dump controllers :-D .

Oh I used that last one and attached it to the metal $7.00 mole chaser from HF.

On a 10 foot pole latched to the pool.

pretty little LEDs.

Have Fun

Bruce S

[ghurd]

Consider them in the mail.