Blue beam laser distance meter

[adam1]

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.

 

[eladlad]

Hi Adam, the one on the link, like (probably) all of the distance meters is with red laser and the film stock I use is sensitive to this wavelength, which means it will show on film. What I need is a wavelength as low as possible so that the eye will see but the stock will not.
And yes, you're probably right about those that use the laser to measure. the ultrasonic ones, however, use sound waves (sonar) for measuring and the laser is just for aiming at the target.

 

[adam1]

My friend has one of those kinds of measurers and I'm pretty sure that the laser will only turn on when you push a specific laser button on the device. Otherwise you could always just put some black electrical tape over the laser opening Regardless, I don't think that it's going to be possible to just swap over the diode. Maybe you could find a way to attach a cheap 405nm ebay pointer to the measurer and still make it look good?