LASERS

Beams!

I like Lasers. They make me happy :)

Over the years I've built, programed, and worked with various laser projection systems and optical setups. Everything from live concerts to optical holography. My first projector was for a multi-touch table designed for use in bars. The system would allow users to not only order drinks, but also control the laser by projecting text, images, and animations. The user could select various effects to modify the laser and create different light shows.

From there I continued to explore their uses and construction. My main area of interest was entertainment technology. However I had the opportunity to create both white light and laser light reflection and transmission holograms at the University of Rochester, which was fantastic!

To the left is a touch-OSC interface I made to run some lasers wirelessly!

My home made testing laser, built using a 20mw 520nm laser diode. I made some custom electronics to drive the diode and provide blanking (switching) capability. I used two closed-loop 30kpps galvanometers to steer the beam. I sourced an ILDA and DMX logic board to serve as an interface between the galvo drivers and my control software.

The whole unit was packaged up in an aluminum enclosure. I added all the back panel controls and provided a key switch to regulate the laser output power from 20mw down to 5mw for safety. I currently use this laser as a benchmark for software and testing.

One of the challenges with the test laser was airflow. Because all the components were packed in very tight, I had to carefully plan out the flow path. Air is taken in on the right by a fan, blown through a filter, three heat sinks and galvos, before exiting the front. I would have preferred an entirely sealed optical system, but didn't have the materials to build it.

Tuning of the laser was done by using the ILDA test pattern and carefully adjusting the gain, offset, drive, feedback, and dampening on the galvanometer amps. Other tuning aspects like timing and blanking can be tunes in software.

For my next laser, I'd like to get much faster galvos, around 60 to 100 kpps (thousand points per second). I'd also like to have fully mixable RGB.

The First Projector

My first laser projector was built for a school project called "socialaser". It was very large and not very fast, but served as a great intro into their design and construction. This was a 20mw green salvaged from some industrial equipment. Blanking was done via a shutter attached to a galvo. This laser used a "proprietary" parallel port protocol which was quite cumbersome to work with, and had issues with some long cable runs we were using. To fix this we built a small buffer/driver circuit that would clean and re-transmit the signal partway down the line.