What is the service life of a stepper motor working 24/7

[trastikata]

Tim, what is the refractive index of the fluid, can you use a bar code scanner and band with black strips taped on the opposite side of the meniscus?

[TimB]

Sorry using a bar code would not help.

If you place a slit at the back and illuminate it the light is magnified. This is what my camera system uses. The fact that the line is magnified where the water is. It works great. However as you can see from the image of the enclosure I posted above, the camera has to be a way back to get the image of the whole tube. Even using a 28mm lens you need to be 100mm+ back and then you still have loads of distortion.

Tim