UV sensor ML8511

[visnja30]

On board is 3V3 voltage regulator so I think it must work with 5V input voltage.

[Scampy]

can you provide a link to the actual module you have. Most of the hits from Google suggest the unit is 3.3v, with a pull up resistor between EN and +3.3v and show no regulator... It would also suggest that the voltage out will be from 0 to +3.3v and not 5v that you might expect.

[visnja30]

http://www.ebay.com/itm/351494135550...%3AMEBIDX%3AIT

I know that the maximum voltage from the module is 3.3volts and my PIC AD module can measure 5 volt maximum.Is that problem?

[Gusse]

It seems that it is challenging to calculate accurate UV-Index (0-11+), as you would like to do.
Index is weighted using 3 different wavelengths and this broadband UV sensor covers all of them.
Problem is that there is just one output value for all of them.

Wavelenghts and weighting:
295 nm -> 1x , 305 nm -> 0.22x , and 325 nm -> 0.003x
How is the UV-Index Calculated?

Basically you could generate your own multiplier, based on above values and hands-on testing.

About operating voltages, even there is 3.3v LDO for chips itself, EN (enable pin) still need to be in spec. Put voltage divider between PIC and sensor.
ADC is not a problem, measure & scale result (1v -> 0, 3v -> 1023, 10-bit ADC)

[visnja30]

ADC is not a problem, measure & scale result (1v -> 0, 3v -> 1023, 10-bit ADC) ...... Yes it is problem

This is my problem I can measure voltage from sensor but how to scale it to UV intensity from datasheet.

I change the power supply to 3.3V and EN pin is connected to VCC pin.

[Gusse]

ADC is not a problem, measure & scale result (1v -> 0, 3v -> 1023, 10-bit ADC) ...... Yes it is problem
This is my problem I can measure voltage from sensor but how to scale it to UV intensity from datasheet.

In Lapis website, they have graph including UV-index.
1V = 0 UV-Index
3V = 15 UV-Index

Don't know how they have calculated that, but lets take it as it is.

Scaling ADRaw: 310 (1V) - 925 (3V) to UVIndex: 0 -15

If AD_Raw < 310 THEN AD_Raw = 310
UVIndex = (((AD_Raw * 4)/17)-71)/10

Above is approximation for accurate calculation formula. It should be close enough, but if it is not then alternate parameters...
Remember that intermediate results (step by ste) must remain as an integer value