Laserbee Power meter, great product.

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

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

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

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

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.

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

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.

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