- Jan 22, 2013
On ebay you can find a few, such as this one, LCD Monitor Digital Ultrasonic Distance Measurer With Laser Pointer DM200 5 | eBay quite cheaply by searching "Ultrasonic Distance Meter". As for switching the diodes, I have a feeling that that wouldn't work. As I understand it, the laser distance meters work by comparing the phase shift of the light that returns to the unit compared to the light that left the unit. Different wavelengths I think would undergo a different phase shift and the unit would be calibrated to the specific wavelength of the preinstalled diode. Someone please correct me if I am wrong, this is just what I could understand after a quick google and being halfway through high school physics.