How avoid the response of a PIN photodiode for sunlight?

[Dhanushka]

Hi,

Currently, I am working on a project, a flame is needed to be identified some considerable distance(at least 10 m). I used a cheap general PIN photodiode and current to voltage converter referring a Texas instruments application note.

Datasheet for a similar photodiode: https://www.vishay.com/docs/81503/bpv10nf.pdf

But this is not I used, I assumed that, that has similar character.

Texas instruments application note for current to voltage converter: https://www.ti.com/lit/ug/tidu535/tidu535.pdf?ts=1625066511744&ref_url=https%253A%252F%252Fwww.google.com%252F

I build this circuit on a piece of perfboard raising the photodiode cathode and inverting input of the opamp to prevent leakage currents. I used TL082 opamp instead the one used in AP note above because I only needed the DC response.

According to the datasheet, the photodiode response only for about 950 nm wavelength. That is true when I tested at night this can identify a match fire well from about 1 m distance even the indoor lights are presents. 

But the problem is under the daylight the opamp saturates without a fire. Then I raised the supply voltage up to 12 V, down the feedback resistor to about 15 kohms and tested again that little bit works. But due to bright sunlight that sometimes goes high voltages. 

According to the Vishay datasheet, the reverse current of the photodiode rise only if the IR radiation is more than 1 mW/cm^2 for about 950 nm. As I know the solar has 950 nm IR radiation of 0.1  mW/cm^2. So, this should not be response for sunlight. But I am in a tropical country, the radiation may differ.

But I know the suitable sensor is pyroelectric flame sensor. They are too much costly. That's why I use these ones.

So, my problems are,

1. May this a fake PIN photodiode?
2. Is this sensor response other radiations like UV?
3. Is there a way to prevent this sunlight IR radiation? (using a filter without disturbing fire response)
4. Should I use a pattern recognition thing with AC response to detect a fire?

Thanks.