Laser + Optical Sensor

I am working on a project that will essentially involve a string of lasers in one end of a tube and optical sensors on the other end. The idea is that when the laser beam is interrupted the arduino will know.

First Set of Questions:

  • Where can I get a laser which works for this purpose? Would I be able to take lasers from old compact disc players or is it more complicated than that? (would something like this ( be easy enough to use?)

The second aspect of this project is that there will also be some sort of ambient light in the tube for less fine grained sensing (less on/off signal, more voltage level signal if that makes any sense).

Second Set of Questions:

  • Are there specific photo sensors which differentiate between types of light or will I have to seal of half the tube (length wise)so that these two light elements don't interact?

Thank you in advance!

For their low cost and ease of use I would suggest buying a cheap laser pointer and removing the "head" section from it. You can also find these modules on eBay or the like; I'd suggest paying the little bit extra and getting modules that are focusable.

Phototransistors and photoresistors do not reject wavelengths of light well but rather are just a little more sensitive to certain wavelengths.

A laser pointed at any detector will result in a lot of reflection to the sides and you'll need to shroud each detector to reduce that problem.

Are there specific photo sensors which differentiate between types of light

You can do things with filters in front of the sensors to distinguish different colours of light.

If you are thinking of powering a laser diode read this:-