LDR, ADC 10 bit, LUX

[Don_dody]

I use LDR as a light sensor. Its output is directly connected to my ADC which is included already in my AVR. The ADC is 10 bit. Now I want to convert the ADC value (0 up to 1023) into lux. Sine I don't have any commercial luxmeter, so can anyone help me how to convert this adc value into lux ?

I know the LDR maybe different with mine, but let just ignore it for now.

Thanks.

 

[tpetar]

You need one of two things, before making calculations.

1. LDR data.

2. Precize LUX meter.



In redneck style you can use LDR to some well known light source as new CFL lamp (you can see how many lumens lamp have on lamp box), and meter light with LDR, then use opamp to make 0-5V range for uC ADC input, and make calc.




See this two projects:

https://320volt.com/lux-metre-devresi-attiny26-16-isik-olcumu/

https://embedded-lab.com/blog/?p=4330

:wink: