Sensing ambient light

[premkumar9]

Hi,
I need to sense the ambient light for controlling the intensity of a street flash light. Planning to use an LDR. The circuit will be in a box under the solar panel. Should I take out the LDR through wire connection and face it upwards (to avoid vehicle head lights directly falling on it).

 

[PhillDubya]

When you say "street flash light", what do you mean?

As far as oncoming car headlights, just face it in a direction perpendicular to the direction of the headlights.

On another note, have you considered using one of these: OPT101 from Texas Instruments . I just finished building a project using one of these, for a light intensity project, and they work great. Just send the voltage to the ADC of a uController of your choice, with whatever logic you want to use.

 

[audioguru]

Maybe in India the street lights flash on and off all night? Because the electricity fails so frequently?

 

[premkumar9]

Maybe in India the street lights flash on and off all night? Because the electricity fails so frequently?

This is how you made 14043 posts in a technical forum?

 

[HarveyH42]

This is how you made 14043 posts in a technical forum?

Pretty much...

 

[audioguru]

There are many requests on these forums for inverters and crystal controlled clocks from people in India.
Their electricity fails often and the voltage and frequency vary all over the place.
The power meters are bypassed so that electricity is stolen and even the copper wires are stolen.

It is a different world over there.
Unbelievable.

 

[premkumar9]

It is a different world over there.
Unbelievable.

How long you were in India?

 

[transistor495]

The power meters are bypassed so that electricity is stolen and even the copper wires are stolen.

How long you were in India?

funny.........!

 

[kchriste]

The circuit will be in a box under the solar panel.

I wonder if you could use the solar panel output voltage for sensing also. Have you checked the output characteristics of the panel when the light is low and it is no longer charging the battery?

 

[transistor495]

LDR facing upwards will catch dust. Just face it towards forest horizontal to ground. Keep it away from direct sunlight. Your circuit is okey?

 

[premkumar9]

I wonder if you could use the solar panel output voltage for sensing also. Have you checked the output characteristics of the panel when the light is low and it is no longer charging the battery?

I use a Charge Controller and battery.

 

[premkumar9]

forest horizontal to ground.

What is that? Can you clarify?

 

[premkumar9]

I use a Charge Controller and battery.

Charge controller will give me constant output voltage.

 

[premkumar9]

funny.........!

Oh... I didn't mean that

 

[transistor495]

What is that? Can you clarify?

Here's a typical street arrangement mine

 

[premkumar9]

Here's a typical street arrangement mine

Thank you. Got from net OR your own suggestion?

 

[transistor495]

I've used mspaint to draw a simple 'diagramatic representation' for u

 

[transistor495]

Sometimes I've gone to my childhood........

Today only I understood MSPaint is such a versatile program to express our artistic skills........

 

[HarveyH42]

Solar Charge Controller

These handle every thing for you, just need solar panel, battery, and lights (load). Even different timing modes (16 I think, been about a year since I hooked mine up), 7 of them flash. It would be difficult to build your own, and save money.

For a solar streetlight, you are going to need some pretty bright lights, don't think LEDs will do it. If people are stealing copper wire, got a hunch a huge solar panel and battery wouldn't last very long...

 

[audioguru]

Oh... I didn't mean that

Funny?
I have never been to India (why would anybody want to ...) but the secrets about their poverty and terrible electricity is all over the world.