Several readers have asked about the possibility of a LEGO Compatible Laser, like in Chapter 2 of "High-Tech LEGO Projects", but in green. Up until now my answer has been: yes, but it's complicated. However, Quarton (quarton.com) has released new green laser products that are much easier to work with. The most important feature is that they take a power voltage of 7-10V, so they can be directly connected to a LEGO 9V battery box. In the photo above I have two types of Quarton lasers. At right is a model number VLM-520-03-LPT (available at digikey.com). Then, for something different, at right is a model VLM-520-29-LPA that generates a cross pattern of 60-degree angle. The video below shows the output beams from both lasers.
I've been working with new designs for the mounts. The cross-beam laser in the photo at the top of the screen uses the design described in "High-Tech LEGO Projects". But since I have a new 3D printer, I tried printing a mount, as shown in the figure below.
And I also found a new way to connect the power supply from a 9V battery box using a Crazy Circuits (crazycircuits.com) component. See my blog post on "LEGO Circuit Boards" for more information on these components. The device used here is a screw terminal adapter, giving a terminal to attach the wires from the laser diode module. A soldered connection is better (as described in "High Tech LEGO Projects"), but here's an alternative if you don't want to get into soldering.