Add Photocell to circuit

[Richard Spring]

I have a very basic question and a limited knowledge of electronics. I have a 5V DC battery powered LED light that I would like to add a photocell to the circuit. The purpose of the photocell would be to close the circuit from dusk to dawn. In other words power at night and no power during daylight.

Could you recommend a simple, cheap, small photocell I could purchase and how to add to the circuit.

Thank you in advance for your assistance.

Richard Spring

 

[alec_t]

Welcome to ETO!
Use a CdS cell. Google "dark detect circuit",

 

[AnalogKid]

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This makes a signal that goes down to GND when illuminated above an adjustable threshold. This can drive an external transistor aw a switch. Any idea how much current your light draws?

ak

 

[Richard Spring]

No idea on current draw, but only using 3 AA batteries to power.

 

[gophert]

Can you post a photo of the 5v LED you are talking about? Also, what kind of brightness are you expecting? For example, do you want to see a red dot from 10m away at night? Do you expect it to illuminate your patio? What?
also, how long do you expect the 3 AA batteries to last?

 

[Richard Spring]

 

[Richard Spring]

See picture of the circuit I am using. I know it has a timer, but would like to add photocell to turn off during daytime. Will have on my patio for summer parties.

 

[gophert]

Your lamp draws 50 to 80mA so about 25 hours of use.
Also, there is a remote control IR receiver of some Type so even putting the photo-cell circuit in series with the LED strand will not turn that off so, I'm not sure if the works is worth the benefit.

 

[Mickster]

The black blob (COB), in the center of the green PCB at the top of the battery compartment, is most-likely the 'brains' behind the selection of the flashing/pulsing/fading, and IR remote control for the LED string.

If this device 'remembers' the last state it was in, when it was switched off, then continues to operate in that state, you may have some success.
alec_t's suggestion for a "dark-detector circuit" might be implemented, to cut/restore power supply to this device, and resume the last state.

Some examples:

dark detector circuit using ldr - Google Search

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