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Kinematic Laser Mounts

A project log for Upright Laser Harp

New spin on the laser blocking musical instrument

jonathan-bumsteadJonathan Bumstead 08/16/2019 at 03:430 Comments

The laser mount was the most difficult assembly to test and design. I wanted to be able to steer the laser for alignment with the photoresistors. In my previous laser harp, the lasers would get misaligned when I moved the device and there was no good way to finely adjust the lasers. Kinematic mounts are crucial components for optical systems, so I looked at existing devices for inspiration. All these devices use springs to apply adjustable force at specific locations in the device. My goal was to build kinematic mounts cheap, which meant replacing the metal springs with other materials. In my search, I also came across these LEGO-based kinematic mounts.

My first designs placed the mirrors on kinematic mounts with rubberbands. This worked pretty well, but the mounts were bulky and difficult to put together. I started to think of ways to make wood spring-like so I could avoid the springs and rubber bands. The final design consists of wooden arms with slits in them that made them flexible.

The mount consists of nine parts. First the rear body is put together with glue and four nuts placed inside. This part holds the screws that push the part holding the laser. Two parts holding the laser are glued together with the holes facing the screw. Finally, the three "spring" arms connect the front part and the part holding the laser. The laser is placed into the device later.

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