I'm about to build a Luxmeter. I want it to give me a respons of 1mV/lux and be able to detect 10.000lux.
Here is part of the solution I'm about to use (4. Luxmeter): http://sales.hamamatsu.com/assets/applications/SSD/si_pd_circuit_kspd1043e07.pdf
The problem comes when I want to record the output signal with my CR1000. If I use the single ended input on the ADC I'll have the range of 0-5V and accuracy of 1.333mV (this is not good enough and also, we would only be able to "see" up to 5.000lux). But if I use the differential input of -5V to +5V I'll have the full range and accuracy of 0.667mV witch will work.
But for this to work, I'll use the construction example in the attached pdf and then what? A circuit who can give me negative response added to the coupling point above the "Volt meter" in the example circuit.
Could anyone give me an solution of how this could work?