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How to build Auotmatic Street Lights Control Using LDR and Arduino for 3 LEDs using 3 LDRs Answered

so , what should I do ?

What will be circuit diagram ?

What changes should be done in Program ?

Thank You !
Please Specify Circuit and Programming .
Can I use 3 different Arduino or Use Single Arduino .

4 Replies

iceng (author)2017-12-15

An NPN transistor is OFF while outside light striking the LDR whose low resistance diverts intended base current to GND...

When dark, the LDResistance is very high and the "body res" can supply base current turning the transistor ON which lights the LED strip at night..

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rickharris (author)2017-12-15

1. Detect current ambient light level (analogue input)

2. Check if analogue level is < a set amount (where you want you light to turn on)

3. If not below that level then Turn light off and go back to 1 to check level again.

4. IF the level is low - Turn on your light. - Go back to 1 to check level again.

What you need depends on several things:

You need an arduino with 1 LDR to detect ambient levels if all the lights are close by, if they all operate on the same light level.

Depending on if this is a model or you are really switching fairly high voltage and currents for a real street light in that case you will need a relay to switch the light.

If it is just a standard LED you can drive it direct from your Arduino output.- So you will need 3 free outputs 1 for each light OR you can drive a single transistor or relay that switches power to all of the lights.

You don't really give enough detail.

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iceng (author)rickharris2017-12-15


Depending on proper resistance selection you can make a digital input work too !

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