Laserbee Power meter, great product.

[RGbee]

That's a shame. It would be pretty good idea for an add-on if it were possible

[Banthai]

yes it is possible to incorperate this in a projector

what you need is a beam splitter with a 99% pass 1% reflect prior to the scanners

with this the reflected portion can be sent to the sensor, the display would have to be calibrated to read true output ( 1mw on sensor = 100mw on display )

if i remember rightly this is the sort of thing that Bill is doing in the pangolin Pass system for audience scanning so he can get a real time sample on power output

all the best ..... Karl

[mixedgas]

An ar coated piece of glass will get you your .1% to 1% reflection, and with a diffuser in front of it, a simple silicon detector loaded with about 450-750 ohms will be quite linear and a fraction of the cost. I would not use amorphous silicon ie cheap bluish looking solar cells.

Lexel used a simple loaded silicon cell for ranges of 10 mW to 5 watts with just a diffuser and a bluish corrector filter with 1% linearity.


Steve

[FourDee]

but those were all in the blue/green range, weren't they?
I dont think the detectors are entirely linear from blue to red

[tocket]

Linear in what aspect? Photodiodes are heavily wavelength dependent simply because photons of different wavelengths have different energies. The current of a photodiode is depends on the number of photons that hits it, not on their energy (unlike a thermocouple). That is assuming the quantum yield is the same for all wavelengths in a range, but I think it is for visible light with Si photodiodes.

[FourDee]

I was talking A(or µA) / mW for different wavelengths.

[tocket]

OK, they are fairly linear for a given wavelength, except at the extremes. The slopes (current/absorbed radiant power) for different wavelengths are not the same though, so you will always need to know the wavelength to calculate the power if you use a photodiode.

I think Steve was talking about the linearity for a given wavelength though.

[mixedgas]

if you split off 1% of a typical hobby laser projector, your down in the noise of a thermal detector. Hence the suggestion of silicon. For any given wavelength they are quite linear, and in your projector, you can check one wavelength at a time.

Steve Roberts