About Me

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I previously worked on Virtual Reality and other hardware at Valve.  I currently work at Google[x].

Prior to starting at Valve, I built computer peripherals such as keyboards, mice, and joysticks that were designed to be used inside MRI machines.  My company, Mag Design and Engineering, sold these devices directly to researchers at academic institutions who used them to publish scientific papers in peer-reviewed journals.

After work, I spend time on many different types of projects that usually involve circuit design, machining, material selection, and general fabrication/hacking.  My favorite place to be is my home workshop.

ben dot krasnow at gmail




Wednesday, October 13, 2010

DIY searchlight housing for 1000W xenon arc lamp

Original test run of 1000W arc lamp:

I finally finished the 1000W xenon searchlight project that I started earlier this year. The power supply is a slightly modified arc welder coupled with an automotive ignition coil for the starting pulse.

This is the searchlight's beam shooting skyward behind a large pine tree in my back yard. The beam is very difficult to capture on video.

Thursday, October 7, 2010

Low-cost DIY thermal imaging -- liquid crystal paint testing

I am trying to develop a low-cost DIY thermal imaging device. The commercially available thermal imaging cameras still cost well over $1000 because of high production costs and low demand. Many hobbyists would like to have a cheap thermal imaging camera even if performance is not as good as commercial or military units. My goal is to build such a camera.

In this video, I am testing one possible approach: Using a very thin projection screen that is painted with thermochromic liquid crystals. These liquid crystals change color in the temperature range 77*F to 86*F. Ideally, the projection screen housing would be heated (or cooled) to 77*F, so that all incident thermal radiation would raise the screen temperature higher than this, and immediately cause a color change.