Photo diode, laser and sunlight

[nacoolp]

Hi All,

I am working on an application, where I am supposed to detect a laser light by means of a photo diode SFH206K (whose datasheet is attached with the mail) in my circuit also attached with the mail. The problem with whole setup is that my circuit is working perfectly indoors but when tested at outdoors, the photodiodes are triggered by means of sunlight only. Can you suggest me another photodiode or some changes in my current circuit that can avoid this hazzle...??

The capacitors in the circuit diagram are of 100nF.

Thanks in advance.

Nakul

 

[Just4FunReally]

Is it possible to enclose the application in some sort of host to prevent unwanted exposure? You could leave a trap-door sort of hole in it for when it needs to be used, simply lift the door and shine the laser inside. My apologies if this sounds dumb to you but with the information given there doesn't seem to be any reason you can't create a host for it.

Hope I could help out a little. If not, I'm sure the LFP guys will come through for you anyway; they always have for me! :beer:

 

[Sigurthr]

This issue recently came up in a thread where a user wanted to make a laser range finder. The issue at hand is, of course, optical saturation. Unfortunately no means of electrical filtering can remove the effects of optical saturation of the PD sensor. Optical filtration is the only answer.

Now, the degree of filtration needed is dependent upon what kind of signal you are trying to detect, and for that I need to know more about your application.

The general answer I can give is that you need to block off-axis ambient light (PD at the end of a long narrow tube works great!) and filter out as much non-laser light as you can. Bandpass filters are perfect for the job. If you have a polarized laser you can use polarization filters as well.