Looking for ideas on measuring luminescence.

[david]

Hi All,
I'm looking for ideas on how to measure and compare 4 luminescing samples that slowly change in luminance over a period of some minutes, perhaps using a camera module.
Resolution is not critical and 320x240 (or less) would be quite adequate.  Only needs luminance so doesn't need to be colour.
I was wondering if there were simple camera modules that can be scanned at relatively low speeds (not video rate) and the brightness measured via an ADC.  There seems to be many low cost camera modules but I don't know how much control of speed may be possible, if at all.  I've naively though I may be able to do a couple of nested For-Next loops to scan through the array while summing up pixels that were over a given threshold.
Any thoughts would be welcome.

Cheers,
David 

[trastikata]

Hello David,

why not using inexpensive dedicated ambient light sensor? There're plenty of them on the market, check TI products.

[david]

Hello trastikata,
I took a look at TI and I'm sure you're right - it is the way to go.  I think the OPT3007 would be fine.  The effective dynamic range is incredible (23bits!) and likewise the spectral tracking to the human eye, not that I need that.
Many thanks for your input.  You always add value to any discussion.

Cheers,
David