I have a pair of cheap IR emitter and receiver and I want to make a project that I need to measure the intensity of the signal that reaches the phototransistor when it passes through different materials.
With these eletronics that I have can I get this readings and if so how accurate and realible will it be?
And what kind of interferance should I expect?
IR333C.pdf (273 KB)
PT333-3B.pdf (247 KB)
The answer depends on the type of material and its thickness.
For quantitative measurements, use a photodiode instead, with a proper amplifier. Photodiode amplifier overview (pdf)
The emitter, sample and detector should be in a completely dark chamber.
Any material that alters the optical path (ie is diffusing or refracting) will spoll any measurement
of absorption by diverting some of the light. This can be minimized by flood-illumination through
a diffuser so that the light is already at constant intensity indepedent of direction.
As you haven't said what the materials are this might, or might not, be relevant.