Light activated switch/relay

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Nikkanochi

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On the third page is schematics. Unfortunately, I am not very good with schematics but my question is: I need relay that will turn relay ON if light is exceed certain intensity. Is there way to rewire this unit so it will do exactly what I want? I will have to calibrate level of light on which relay will click ON therefore variable resistor will be very helpful. I do understand this device already have one. I will appreciate any help and advice. If you happen to know where I can find complete unit or a Kit with properties I am looking for - I will appreciate this information also.
Thank you VERY much in advance,
Respectfully, Nikkanochi
 

If you want to calibrate somehow a light sensor you have to use a comparator rather than single discrete transistor ..
Here is an example that uses comparator (LM311) but you can replace it with almost any opamp (eg. LM358, ..) ..
https://www.circuitstoday.com/light-activated-switch-circuit
With P4 you can adjust sensitivity, whereas with voltage divider R3/R4 (both can be replaced with a potentiometer) you can 'calibrate" light level ..

Rgds,
IanP
:|
 

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    Nikkanochi

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Thank You Very Much!
By any chance do you know any ready modules or kits that would be easy to built or adgust to scheme you suggest? I would speculate that it would be very similar to Dark activated switch/relay but with changed action on relay...
Again, thank you a lot for you expertise!
Sincerely,
Nikkanochi
 

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